We are searching data for your request:
Upon completion, a link will appear to access the found materials.
What if early SETI investigations had focused on our own solar system, rather than distant stars?
Given the technology that existed around the 1950s, how much surveillance would humanity be able to do? This is in the era between Sputnik and Apollo 1, so various governments and scientific organizations would have had different equipment and personnel to devote to the task. So this change of focus would have impacted the way various governments, scientific organizations and civilian groups approached the search for intelligent life in space, and altered the focus of technological development.
What were the near-space observation capabilities of radio telescopes and related devices at that time? For example if Cornell University's Project Ozma or Ohio State University's Big Ear were used to look more closely at our own solar system, rather than distant stars, what would they have been able to detect or confirm?
If answers can address what kinds of information mid-20th-century technology could have detected, what level of detail, how often various regions could be scanned etc - that would be wonderful. I would also love recommendations about other scientific developments from that era which might be relevant to this topic.
(Note: I'm doing this research for an alternate-history science fiction writing project. I've edited the question to only ask about real, historical science, since the goal is a narrative that accurately represents the past as much as possible.)
The data about the various bodies in the Solar System available from ground-based observations in that era was rather crude. Optical and radio telescopes have improved a lot since then. We now have various ways of compensating for the distortion due to Earth's atmosphere, and sophisticated computer techniques for enhancing the raw data.
Sure, they could have built telescopes with more power and higher resolution, but those devices would still have been limited due to sitting at the bottom of Earth's atmosphere. So it was a major breakthrough when space probes like the Mariner series started sending us up-close data of the planets.
Astronomy books from that era (i.e., the ones I read when I was at school) didn't have a lot of information about the planets, apart from their size, mass, revolution & rotation periods, and approximate atmospheric composition for the gas giants (Uranus & Neptune were classed as gas giants back then). And the number of (major) moons. As for the moons themselves, we knew their orbital periods, but only had a very rough idea of their sizes. It was known that Titan has an atmosphere, though.
Before Mariner 4 (launched on November 28, 1964) we had no good pictures of the surface of Mars: people were still debating whether the canals of Mars were real or some kind of optical illusion. And we had no idea that the atmosphere of Mars is so thin. Hard sci-fi from that era could have Martian colonists walking around without spacesuits. :)
FWIW, here's the best image of Mars from Mariner 4, courtesy of Wikipedia:
As you can see, there's not a lot of detail there, but that image is vastly better than any prior images of the Martian surface (not counting artist's impressions, of course). Many planetary astronomers were quite surprised that Mars had such cratering.
I recall hearing Professor Lovelock about 10 years ago, describing a discussion with his students in the 1960s - what observation would indicate life on another planet? They concluded that spectroscopic analysis would show that the chemistry of the planet was inconsistent with the planet's age. A slower than expected rate of entropy would indicate the presence of life, because the chemistry of Earth life uses photosynthesis to build giant molecules which store energy by absorbing solar radiation
Spectroscopic analysis was used to examine of the atmosphere of Mars in the 19th century, many decades earlier than the context of your question. Before the space race began, scientists had already seen enough to rule out the possibility of life on other planets in the solar system
Lovelock's discussions about extra-terrestrial life led to his Gaia hypothesis, a set of models which demonstrate that Earth's current atmosphere and ocean chemistry emerged from billions of years of life on Earth
Timeline: 50 Years of Spaceflight
On Oct. 4, 2007, the Space Age celebrated the 50th anniversary of the historic launch of Sputnik, the first artificial satellite, by the former Soviet Union.
The space shot also launched the Space Race to the moon between the United States and the Soviet Union. But despite that turbulent beginning, the initial launch has led to five decades of triumphs and tragedies in space science and exploration.
Below is a timeline by Space News and SPACE.com chronicling the first 50 years of spaceflight. You are invited to walk through the half century of space exploration and click related links for more in depth information:
Sometime in the 11th century: China combines sulfur, charcoal and saltpeter (potassium nitrate) to make gunpowder, the first fuel used to propel early rockets in Chinese warfare.
July 4, 1054: Chinese astronomers observe the supernova in Taurus that formed the Crab Nebula.
Mid-1700s: Hyder Ali, the Sultan of Mysome in India, begins manufacturing rockets sheathed in iron, not cardboard or paper, to improve their range and stability.
March 16, 1926: Robert Goddard, sometimes referred to as the "Father of Modern Rocketry," launches the first successful liquid-fueled rocket.
July 17, 1929: Robert Goddard launches a rocket that carries with it the first set of scientific tools &mdash a barometer and a camera &mdash in Auburn, Mass. The launch was Goddard's fourth.
Feb. 18, 1930: The dwarf planet Pluto is discovered by American astronomer Clyde Tombaugh at Lowell Observatory in Flagstaff, Ariz.
Oct. 3, 1942: Germany successfully test launches the first ballistic missile, the A4, more commonly known as the V-2, and later uses it near the end of European combat in World War II.
Sep. 29, 1945: Wernher von Braun arrives at Ft. Bliss, Texas, with six other German rocket specialists.
Oct. 14, 1947: American test pilot Chuck Yeager breaks the sound barrier for the first time in the X-1, also known as Glamorous Glennis.
Oct. 4, 1957: A modified R-7 two-stage ICBM launches the satellite Sputnik 1 from Tyuratam. The Space Race between the Soviet Union and the United States begins.
Nov. 3, 1957: The Soviet Union launches Sputnik 2 with the first living passenger, the dog Laika, aboard.
Dec. 6, 1957: A Vanguard TV-3 carrying a grapefruit-sized satellite explodes at launch a failed response to the Sputnik launch by the United States.
Jan. 31, 1958: Explorer 1, the first satellite with an onboard telemetry system, is launched by the United States into orbit aboard a Juno rocket and returns data from space.
Oct. 7, 1958: NASA Administrator T. Keith Glennan publicly announces NASA's manned spaceflight program along with the formation of the Space Task Group, a panel of scientist and engineers from space-policy organizations absorbed by NASA. The announcement came just six days after NASA was founded.
Jan. 2, 1959: The U.S.S.R. launches Luna 1, which misses the moon but becomes the first artificial object to leave Earth orbit.
Jan. 12, 1959: NASA awards McDonnell Corp. the contract to manufacture the Mercury capsules.
Feb. 28, 1959: NASA launches Discover 1, the U.S. first spy satellite, but it is not until the Aug. 11, 1960, launch of Discover 13 that film is recovered successfully.
May 28, 1959: The United States launches the first primates in space, Able and Baker, on a suborbital flight.
Aug. 7, 1959: NASA's Explorer 6 launches and provides the first photographs of the Earth from space.
Sept. 12, 1959: The Soviet Union's Luna 2 is launched and two days later is intentionally crashed into the Moon.
Sept. 17, 1959: NASA's X-15 hypersonic research plane, capable of speeds to Mach 6.7, makes its first powered flight.
Oct. 24, 1960: To rush the launch of a Mars probe before the Nov. 7 anniversary of the Bolshevik Revolution, Field Marshall Mitrofan Nedelin ignored several safety protocols and 126 people are killed when the R-16 ICBM explodes at the Baikonur Cosmodrome during launch preparations.
Feb. 12, 1961: The Soviet Union launches Venera to Venus, but the probe stops responding after a week.
April 12, 1961: Yuri Gagarin becomes the first man in space with a 108-minute flight on Vostok 1 in which he completed one orbit.
May 5, 1961: Mercury Freedom 7 launches on a Redstone rocket for a 15-minute suborbital flight, making Alan Shepard the first American in space.
May 25, 1961: In a speech before Congress, President John Kennedy announces that an American will land on the moon and be returned safely to Earth before the end of the decade.
Oct. 27, 1961: Saturn 1, the rocket for the initial Apollo missions, is tested for the first time.
Feb. 20, 1962: John Glenn makes the first U.S. manned orbital flight aboard Mercury 6.
June 7, 1962: Wernher von Braun backs the idea of a Lunar Orbit Rendezvous mission.
July 10, 1962: The United States launches Telstar 1, which enables the trans-Atlantic transmission of television signals.
June 14, 1962: Agreements are signed establishing the European Space Research Organisation and the European Launcher Development Organisation. Both eventually were dissolved.
July 28, 1962: The U.S.S.R launches its first successful spy satellite, designated Cosmos 7.
Aug. 27, 1962: Mariner 2 launches and eventually performs the first successful interplanetary flyby when it passes by Venus.
Sept. 29, 1962: Canada's Alouette 1 launches aboard a NASA Thor-Agena B rocket, becoming the first satellite from a country other than the United States or Soviet Union.
June 16, 1963: Valentina Tereshkova becomes the first woman to fly into space.
July 28, 1964: Ranger 7 launches and is the Ranger series' first success, taking photographs of the moon until it crashes into its surface four days later.
April 8, 1964: Gemini 1, a two-seat spacecraft system, launches in an unmanned flight.
Aug. 19, 1964: NASA's Syncom 3 launches aboard a Thor-Delta rocket, becoming the first geostationary telecommunications satellite.
Oct. 12, 1964: The Soviet Union launches Voskhod 1, a modified Vostok orbiter with a three-person crew.
March 18, 1965: Soviet cosmonaut Alexei Leonov makes the first spacewalk from the Voskhod 2 orbiter.
March 23, 1965: Gemini 3, the first of the manned Gemini missions, launches with a two-person crew on a Titan 2 rocket, making astronaut Gus Grissom the first man to travel in space twice.
June 3, 1965: Ed White, during the Gemini 4 mission, becomes the first American to walk in space.
July 14, 1965: Mariner 4 executes the first successful Mars flyby.
Aug. 21, 1965: Gemini 5 launches on an eight-day mission.
Dec. 15, 1965: Gemini 6 launches and performs a rendezvous with Gemini 7.
Jan. 14, 1966: The Soviet Union's chief designer, Sergei Korolev, dies from complications stemming from routine surgery, leaving the Soviet space program without its most influential leader of the preceding 20 years.
Feb. 3, 1966: The unmanned Soviet spacecraft Luna 9 makes the first soft landing on the Moon.
March 1, 1966: The Soviet Union's Venera 3 probe becomes the first spacecraft to land on the planetVenus, but its communications system failed before data could be returned.
March 16, 1966: Gemini 8 launches on a Titan 2 rocket and later docks with a previously launched Agena rocket &mdash the first docking between two orbiting spacecraft.
April 3, 1966: The Soviet Luna 10 space probe enters lunar orbit, becoming the first spacecraft to orbit the Moon.
June 2, 1966: Surveyor 1, a lunar lander, performs the first successful U.S. soft landing on the Moon.
Jan. 27, 1967: All three astronauts for NASA's Apollo 1 mission suffocate from smoke inhalationin a cabin fire during a launch pad test.
April 5, 1967: A review board delivers a damning report to NASA Administrator James Webb about problem areas in the Apollo spacecraft. The recommended modifications are completed by Oct. 9, 1968.
April 23, 1967: Soyuz 1 launches but myriad problems surface. The solar panels do not unfold, there are stability problems and the parachute fails to open on descent causing the death of Soviet cosmonaut Vladimir Komarov.
Oct. 11, 1968: Apollo 7, the first manned Apollo mission, launches on a Saturn 1 for an 11-day mission in Earth orbit. The mission also featured the first live TV broadcast of humans in space.
Dec. 21, 1968: Apollo 8 launches on a Saturn V and becomes the first manned mission to orbit the moon.
Jan. 16, 1969: Soyuz 4 and Soyuz 5 rendezvous and dock and perform the first in-orbit crew transfer.
March 3, 1969: Apollo 9 launches. During the mission, tests of the lunar module are conducted in Earth orbit.
May 22, 1969: Apollo 10's Lunar Module Snoopy comes within 8.6 miles (14 kilometers) of the moon's surface.
July 20, 1969: Six years after U.S. President John F. Kennedy's assassination, the Apollo 11 crew lands on the Moon, fulfilling his promise to put an American there by the end of the decade and return him safely to Earth.
Nov. 26, 1965: France launches its first satellite, Astérix, on a Diamant A rocket, becoming the third nation to do so.
Feb. 11, 1970: Japan's Lambda 4 rocket launches a Japanese test satellite, Ohsumi into orbit.
April 13, 1970: An explosion ruptures thecommand module of Apollo 13, days after launch and within reach of the moon. Abandoning the mission to save their lives, the astronauts climb into the Lunar Module and slingshot around the Moon to speed their return back to Earth.
April 24, 1970: The People's Republic of China launches its first satellite, Dong Fang Hong-1, on a Long March 1 rocket, becoming the fifth nation capable of launching its own satellites into space.
Sept. 12: 1970: The Soviet Union launches Luna 16, the first successful automated lunar sample retrieval mission.
April 19, 1971: A Proton rocket launches thefirst space station, Salyut 1, from Baikonur.
June 6, 1971: Soyuz 11 launches successfully, docking with Salyut 1. The three cosmonauts are killed during re-entry from a pressure leak in the cabin.
July 26, 1971: Apollo 15 launches with a Boeing-built Lunar Roving Vehicle and better life-support equipment to explore the Moon.
Oct. 28, 1971: The United Kingdom successfully launches its Prospero satellite into orbit on a Black Arrow rocket, becoming the sixth nation capable of launching its own satellites into space.
Nov. 13, 1971: Mariner 9 becomes the first spacecraft to orbit Mars and provides the first complete map of the planet's surface.
Jan. 5, 1972: U.S. President Richard Nixon announces that NASA is developing a reusable launch vehicle, the space shuttle.
March 3, 1972: Pioneer 10, the first spacecraft to leave the solar system, launches from Cape Kennedy, Fla.
Dec. 19, 1972: Apollo 17, the last mission to the moon, returns to Earth.
May 14, 1973: A Saturn V rocket launches Skylab, the United States' first space station.
March 29, 1974: Mariner 10 becomes the first spacecraft to fly by Mercury.
April 19, 1975: The Soviet Union launches India's first satellite, Aryabhata.
May 31, 1975: The European Space Agency is formed.
July 17 1975: Soyuz-19 and Apollo 18 dock.
Aug. 9, 1975: ESA launches its first satellite, Cos-B, aboard a Thor-Delta rocket.
Sept. 9, 1975: Viking 2, composed of a lander and an orbiter, launches for Mars.
July 20, 1976: The U.S. Viking 1 lands on Mars, becoming the first successful Mars lander.
Aug. 20, 1977: Voyager 2 is launched on a course toward Uranus and Neptune.
Sept. 5, 1977: Voyager 1 is launched to perform flybys of Jupiter and Saturn.
Sept. 29, 1977: Salyut 6 reaches orbit. It is the first space station equipped with docking stations on either end, which allow for two vehicles to dock at once, including the Progress supply ship.
Feb. 22, 1978: The first GPS satellite, Navstar 1, launches aboard an Atlas F rocket.
July 11, 1979: Skylab, the first American space station, crashes back to Earth in the sparsely populated grasslands of western Australia.
Sept. 1, 1979: Pioneer 11 becomes the first spacecraft to fly past Saturn.
Dec. 24, 1979: The French-built Ariane rocket, Europe's first launch vehicle, launches successfully.
July 18 1980: India launches its Rohini 1 satellite. By using its domestically developed SLV-3 rocket, India becomes the seventh nation capable of sending objects into space by itself.
April 12, 1981: Space Shuttle Columbia lifts off from Cape Canaveral, beginning the first space mission for NASA's new astronaut transportation system.
June 24, 1982: French air force test pilot Jean-Loup Chrétien launches to the Soviet Union's Salyut 7 aboard Soyuz T-6.
Nov. 11, 1982: Shuttle Columbia launches. During its mission, it deploys two commercial communications satellites.
June 18, 1983: Sally Ride aboard the Space Shuttle Challenger becomes the first American woman in space.
Feb. 7, 1984: Astronauts Bruce McCandless and Robert Stewart maneuver as many as 328 feet (100 meters) from the Space Shuttle Challenger using the Manned Maneuvering Unit, which contains small thrusters, in the first ever untethered spacewalks.
April 8, 1984: Challenger crew repairs the Solar Max satellite during a spacewalk.
Sept. 11: 1985: The International Cometary Explorer, launched by NASA&enspin 1978, performs the first comet flyby.
Jan. 24, 1986: Voyager 2 completes the first and only spacecraft flyby of Uranus.
Jan. 28, 1986: Challenger broke apart 73 seconds after launch after its external tank exploded, grounding the shuttle fleet for more than two years.
Feb. 20, 1986: The Soviet Union launches theMir space station.
March 13, 1986: A two-cosmonaut crew launches aboard Soyuz T-15 to power up the Mir space station. During their 18-month mission, they also revive the abandoned Salyut 7, and take parts that are later placed aboard Mir.
June 15, 1988: PanAmSat launches its first satellite, PanAmSat 1, on an Ariane 4 rocket, giving Intelsat its first taste of competition.
Sept. 19, 1988: Israel launches its first satellite, the Ofeq 1 reconnaissance probe, aboard an Israeli Shavit rocket.
Nov. 15, 1988: The Soviet Union launches its Buran space shuttle on its only flight, an unpiloted test.
May 4, 1989: The Space Shuttle Atlantis launches the Magellan space probe to use radar to map the surface of Venus.
Oct. 18, 1989: Shuttle Atlantis launches with Jupiter-bound Galileo space probe on board.
April 7, 1990: China launches the Asiasat-1 communications satellite, completing its first commercial contract.
April 25, 1990: The Space Shuttle Discovery releases the Hubble Space Telescopeinto Earth orbit.
Oct. 29, 1991: The U.S. Galileo spacecraft, on its way to Jupiter, successfully encounters the asteroid Gaspra, obtaining images and other data during its flyby.
April 23, 1992: The U.S. Cosmic Background Explorer spacecraft detects the first evidence of structure in the residual radiation left over from the Big Bang that created the Universe.
Dec. 28, 1992: Lockheed and Khrunichev Enterprise announce plans to form Lockheed-Khrunichev-Energia International, a new company to market Proton rockets.
June 21, 1993: Shuttle Endeavour launches carrying Spacehab, a privately owned laboratory that sits in the shuttle cargo bay.
Dec. 2, 1993: Endeavour launches on a mission to repair theHubble Space Telescope.
Dec. 17, 1993: DirecTV launches its first satellite, DirecTV 1, aboard an Ariane 4 rocket.
Feb. 7, 1994: The first Milstar secure communications satellite launches. The geosynchronous satellites are used by battlefield commanders and for strategic communications.
Oct. 15, 1994: India launches its four-stage PolarSatellite Launch Vehicle for the first time.
Jan. 26, 1995: A Chinese Long March rocket carrying the Hughes-built Apstar-1 rocket fails. The accident investigation, along with the probe of a subsequent Long March failure that destroyed an Intelsat satellite, leads to technology-transfer allegations that ultimately result in the U.S. government barring launches of American-built satellites on Chinese rockets.
Feb. 3, 1995: The Space Shuttle Discovery launches anddocks with the Mir space station.
March 15, 1995: Aerospace giants Lockheed Corp. and Martin Marietta Corp. merge.
July 13, 1995: Galileo releases its space probe, which is bound for Jupiter and its moons.
Aug. 7, 1996: NASA and Stanford University researchers announce a paper contending that a 4-billion-year-old Martian meteorite, called ALH 84001, found in Antarctica in 1984, contains fossilized traces of carbonate materials that suggest primitive life might once have existed on Mars. That contention remains controversial.
May 5, 1997: Satellite mobile phone company Iridium launches its first five satellites on a Delta 2 rocket.
June 25 1997: An unmanned Russian Progress supply spacecraft collides with the Mir space station.
July 4, 1997: The Mars Pathfinder lander and its accompanying Sojourner rover touch down on the surface of Mars.
Aug. 1, 1997: The Boeing Co. and the McDonnell Douglas Corp. merge, keeping Boeing's name.
Feb. 14, 1998: Globalstar, a satellite mobile telephone company, launches its first four satellites on a Delta 2 rocket.
Sept. 9, 1998: A Russian Zenit 2 rocket launches and subsequently crashes, destroying all 12 Loral-built Globalstar satellites aboard. The payload had an estimated value of about $180 million.
Nov. 20, 1998: Russia's Zarya control module, the first segment of the International Space Station, launches into space and unfurls its solar arrays.
March 27, 1999: Sea Launch Co. launches a demonstration satellite, successfully completing its first launch.
July 23, 1999: The Chandra X-ray observatory, NASA's flagship mission for X-ray astronomy, launches aboard the Space Shuttle Columbia.
Aug. 13, 1999: Iridium files for Chapter 11 bankruptcy, after being unable to pay its creditors. Iridium Satellite LLC later acquired the original Iridium's assets from bankruptcy.
Nov. 19, 1999: China successfully test launches the unmanned Shenzhou 1.
July 10, 2000: Europe's largest aerospace company, European Aeronautic Defence and Space Co., EADS, forms with the consolidation of DaimlerChrysler Aerospace AG of Munich, Aerospatiale Matra S.A. of Paris, and Construcciones Aeronáuticas S.A. of Madrid.
March 18, 2001: After launch delays with XM-1, XM Satellite Radio's XM-2 satellite becomes the company's first satellite in orbit when it is launched by Sea Launch Co.
March 23, 2001: After being mothballed in 1999, Mir descends into the Earth's atmosphere and breaks up over the Pacific Ocean.
May 6, 2001: U.S. entrepreneur Dennis Tito returns to Earth aboard a Russian Soyuz spacecraft to become the world's first paying tourist to visit the International Space Station.
Aug. 29, 2001: Japan's workhorse launch system, the two-stage H-2A rocket, launches for the first time.
Feb. 15, 2002: After having trouble selling its satellite mobile phone service, Globalstar voluntarily files for Chapter 11 bankruptcy protection from escalating creditor debt. The company emerged from bankruptcy April 14, 2004.
Feb. 1, 2003: The Space Shuttle Columbia disintegrates as it re-enters the Earth's atmosphere, killing the crew. Damage from insulating foam hitting the orbiter's leading wing on liftoff is later cited as the cause of the accident.
Aug 22, 2003: The VLS-V03, a Brazilian prototype rocket, explodes on the launch pad at Alcántara killing 21 people.
Aug. 25, 2003: NASA launches the Spitzer Space Telescope aboard a Delta rocket.
Oct. 1, 2003: Japan's two space agencies, the Institute of Space and Astronautical Science and the National Space Development Agency of Japan, merge into the Japan Aerospace Exploration Agency.
Oct. 15, 2003: Yang Liwei becomes China's first taikonaut, having launched aboard Shenzhou 5.
Jan. 4, 2004: The first Mars Exploration Rover, Spirit, lands on Mars. Its twin, Opportunity lands Jan. 25.
Jan. 14, 2004: President George W. Bush advocates space exploration missions to the moon and Mars for NASA in his Vision for Space Exploration speech.
Sept. 20, 2004: India launches its three-stage Geosynchronous Satellite Launch Vehicle for the first time.
Oct. 4, 2004: Scaled Composites' SpaceShipOne piloted craft wins the X Prize by flying over 100 kilometers above Earth twice within two weeks.
July 26, 2005: Discovery becomes the first shuttle to launch since the Columbia disaster more than two years before. While the crew returned safely, the loss of several pieces of foam debris prompted further investigation, which delayed future shuttle missions.
Oct. 12, 2005: A two-taikonaut crew launches aboard the Chinese Shenzhou 6.
Oct 19, 2005: The last of the Martin Marietta-built Titan 4 heavy-lift rockets launches.
Jan. 19, 2006: New Horizons, NASA's first-ever mission to the dwarf planet Pluto and its moons, launches atop an Atlas 5 rocket from Cape Canaveral, Florida. Flies past Jupiter one year later in what is billed as NASA's fastest mission to date.
July 3, 2006: Intelsat acquires fellow fixed satellite service provider PanAmSat for $6.4 billion.
July 4, 2006: NASA's second post-Columbia accident test flight, STS-121 aboard Discovery, begins a successful space station-bound mission, returning the U.S. orbiter fleet to flight status.
Sept. 9., 2006: NASA resumes construction of the International Space Station with the launch of the shuttle Atlantis on STS-115 after two successful return to flight test missions. Atlantis' launch occurs after nearly four years without a station construction flight.
Oct. 11, 2006: Lockheed Martin completes the sale of its majority share in International Launch Services to Space Transport Inc. for $60 million.
Jan. 11, 2007: China downs one of its weather satellites, Fengyun-1C, with a ground launched missile. In doing so, China joins Russia and the United States as the only nations to have successfully tested anti-satellite weapons.
April 6, 2007: The European Commission approves the acquisition of French-Italian Alcatel Alenia by Paris-based Thales, thus creating satellite manufacturer Thales Alenia Space.?
Aug. 8, 2007: NASA's Space Shuttle Endeavour launches toward the International Space Station on the STS-118 construction mission. The shuttle crew includes teacher-astronaut Barbara Morgan, NASA's first educator spaceflyer, who originally served backup for the first Teacher-in-Space Christa McAuliffe who was lost with six crewmates during the 1986 Challenger accident.
Sept. 27, 2007: Dawn, the first ion-powered probe to visit two celestial bodies in one go, launches on an eight-year mission to the asteroid Vesta and dwarf planet Ceres, the two largest space rocks in the solar system.
Oct. 1, 2007: NASA astronaut Peggy Whitson, the first female commander of the International Space Station, prepares for an Oct. 10 launch with her Expedition 16 crewmate Yuri Malenchenko and Malaysia's first astronaut Sheikh Muszaphar Shukor. Whitson, and NASA's second female shuttle commander Pamela Melroy, will command a joint space station construction mission in late October.
Oct. 4, 2007: The Space Age turns 50, five decades after the historic launch of Sputnik 1.
The outer layers of the Earth are divided into the lithosphere and asthenosphere. The division is based on differences in mechanical properties and in the method for the transfer of heat. The lithosphere is cooler and more rigid, while the asthenosphere is hotter and flows more easily. In terms of heat transfer, the lithosphere loses heat by conduction, whereas the asthenosphere also transfers heat by convection and has a nearly adiabatic temperature gradient. This division should not be confused with the chemical subdivision of these same layers into the mantle (comprising both the asthenosphere and the mantle portion of the lithosphere) and the crust: a given piece of mantle may be part of the lithosphere or the asthenosphere at different times depending on its temperature and pressure.
The key principle of plate tectonics is that the lithosphere exists as separate and distinct tectonic plates, which ride on the fluid-like (visco-elastic solid) asthenosphere. Plate motions range up to a typical 10–40 mm/year (Mid-Atlantic Ridge about as fast as fingernails grow), to about 160 mm/year (Nazca Plate about as fast as hair grows).  The driving mechanism behind this movement is described below.
Tectonic lithosphere plates consist of lithospheric mantle overlain by one or two types of crustal material: oceanic crust (in older texts called sima from silicon and magnesium) and continental crust (sial from silicon and aluminium). Average oceanic lithosphere is typically 100 km (62 mi) thick  its thickness is a function of its age: as time passes, it conductively cools and subjacent cooling mantle is added to its base. Because it is formed at mid-ocean ridges and spreads outwards, its thickness is therefore a function of its distance from the mid-ocean ridge where it was formed. For a typical distance that oceanic lithosphere must travel before being subducted, the thickness varies from about 6 km (4 mi) thick at mid-ocean ridges to greater than 100 km (62 mi) at subduction zones for shorter or longer distances, the subduction zone (and therefore also the mean) thickness becomes smaller or larger, respectively.  Continental lithosphere is typically about 200 km thick, though this varies considerably between basins, mountain ranges, and stable cratonic interiors of continents.
The location where two plates meet is called a plate boundary. Plate boundaries are commonly associated with geological events such as earthquakes and the creation of topographic features such as mountains, volcanoes, mid-ocean ridges, and oceanic trenches. The majority of the world's active volcanoes occur along plate boundaries, with the Pacific Plate's Ring of Fire being the most active and widely known today. These boundaries are discussed in further detail below. Some volcanoes occur in the interiors of plates, and these have been variously attributed to internal plate deformation  and to mantle plumes.
As explained above, tectonic plates may include continental crust or oceanic crust, and most plates contain both. For example, the African Plate includes the continent and parts of the floor of the Atlantic and Indian Oceans. The distinction between oceanic crust and continental crust is based on their modes of formation. Oceanic crust is formed at sea-floor spreading centers, and continental crust is formed through arc volcanism and accretion of terranes through tectonic processes, though some of these terranes may contain ophiolite sequences, which are pieces of oceanic crust considered to be part of the continent when they exit the standard cycle of formation and spreading centers and subduction beneath continents. Oceanic crust is also denser than continental crust owing to their different compositions. Oceanic crust is denser because it has less silicon and more heavier elements ("mafic") than continental crust ("felsic").  As a result of this density stratification, oceanic crust generally lies below sea level (for example most of the Pacific Plate), while continental crust buoyantly projects above sea level (see the page isostasy for explanation of this principle).
Three types of plate boundaries exist,  with a fourth, mixed type, characterized by the way the plates move relative to each other. They are associated with different types of surface phenomena. The different types of plate boundaries are:  
- Divergent boundaries (Constructive) occur where two plates slide apart from each other. At zones of ocean-to-ocean rifting, divergent boundaries form by seafloor spreading, allowing for the formation of new ocean basin. As the ocean plate splits, the ridge forms at the spreading center, the ocean basin expands, and finally, the plate area increases causing many small volcanoes and/or shallow earthquakes. At zones of continent-to-continent rifting, divergent boundaries may cause new ocean basin to form as the continent splits, spreads, the central rift collapses, and ocean fills the basin. Active zones of mid-ocean ridges (e.g., the Mid-Atlantic Ridge and East Pacific Rise), and continent-to-continent rifting (such as Africa's East African Rift and Valley and the Red Sea), are examples of divergent boundaries.
- Convergent boundaries (Destructive) (or active margins) occur where two plates slide toward each other to form either a subduction zone (one plate moving underneath the other) or a continental collision. At zones of ocean-to-continent subduction (e.g. the Andes mountain range in South America, and the Cascade Mountains in Western United States), the dense oceanic lithosphere plunges beneath the less dense continent. Earthquakes trace the path of the downward-moving plate as it descends into asthenosphere, a trench forms, and as the subducted plate is heated it releases volatiles, mostly water from hydrous minerals, into the surrounding mantle. The addition of water lowers the melting point of the mantle material above the subducting slab, causing it to melt. The magma that results typically leads to volcanism.  At zones of ocean-to-ocean subduction (e.g. Aleutian islands, Mariana Islands, and the Japaneseisland arc), older, cooler, denser crust slips beneath less dense crust. This motion causes earthquakes and a deep trench to form in an arc shape. The upper mantle of the subducted plate then heats and magma rises to form curving chains of volcanic islands. Deep marine trenches are typically associated with subduction zones, and the basins that develop along the active boundary are often called "foreland basins". Closure of ocean basins can occur at continent-to-continent boundaries (e.g., Himalayas and Alps): collision between masses of granitic continental lithosphere neither mass is subducted plate edges are compressed, folded, uplifted.
- Transform boundaries (Conservative) occur where two lithospheric plates slide, or perhaps more accurately, grind past each other along transform faults, where plates are neither created nor destroyed. The relative motion of the two plates is either sinistral (left side toward the observer) or dextral (right side toward the observer). Transform faults occur across a spreading center. Strong earthquakes can occur along a fault. The San Andreas Fault in California is an example of a transform boundary exhibiting dextral motion.
- Plate boundary zones occur where the effects of the interactions are unclear, and the boundaries, usually occurring along a broad belt, are not well defined and may show various types of movements in different episodes.
It has generally been accepted that tectonic plates are able to move because of the relative density of oceanic lithosphere and the relative weakness of the asthenosphere. Dissipation of heat from the mantle is acknowledged to be the original source of the energy required to drive plate tectonics through convection or large scale upwelling and doming. The current view, though still a matter of some debate, asserts that as a consequence, a powerful source generating plate motion is the excess density of the oceanic lithosphere sinking in subduction zones. When the new crust forms at mid-ocean ridges, this oceanic lithosphere is initially less dense than the underlying asthenosphere, but it becomes denser with age as it conductively cools and thickens. The greater density of old lithosphere relative to the underlying asthenosphere allows it to sink into the deep mantle at subduction zones, providing most of the driving force for plate movement. The weakness of the asthenosphere allows the tectonic plates to move easily towards a subduction zone.  Although subduction is thought to be the strongest force driving plate motions, it cannot be the only force since there are plates such as the North American Plate which are moving, yet are nowhere being subducted. The same is true for the enormous Eurasian Plate. The sources of plate motion are a matter of intensive research and discussion among scientists. One of the main points is that the kinematic pattern of the movement itself should be separated clearly from the possible geodynamic mechanism that is invoked as the driving force of the observed movement, as some patterns may be explained by more than one mechanism.  In short, the driving forces advocated at the moment can be divided into three categories based on the relationship to the movement: mantle dynamics related, gravity related (main driving force accepted nowadays), and earth rotation related.
Driving forces related to mantle dynamics
For much of the last quarter century, the leading theory of the driving force behind tectonic plate motions envisaged large scale convection currents in the upper mantle, which can be transmitted through the asthenosphere. This theory was launched by Arthur Holmes and some forerunners in the 1930s  and was immediately recognized as the solution for the acceptance of the theory as originally discussed in the papers of Alfred Wegener in the early years of the century. However, despite its acceptance, it was long debated in the scientific community because the leading theory still envisaged a static Earth without moving continents up until the major breakthroughs of the early sixties.
Two- and three-dimensional imaging of Earth's interior (seismic tomography) shows a varying lateral density distribution throughout the mantle. Such density variations can be material (from rock chemistry), mineral (from variations in mineral structures), or thermal (through thermal expansion and contraction from heat energy). The manifestation of this varying lateral density is mantle convection from buoyancy forces. 
How mantle convection directly and indirectly relates to plate motion is a matter of ongoing study and discussion in geodynamics. Somehow, this energy must be transferred to the lithosphere for tectonic plates to move. There are essentially two main types of forces that are thought to influence plate motion: friction and gravity.
- Basal drag (friction): Plate motion driven by friction between the convection currents in the asthenosphere and the more rigid overlying lithosphere.
- Slab suction (gravity): Plate motion driven by local convection currents that exert a downward pull on plates in subduction zones at ocean trenches. Slab suction may occur in a geodynamic setting where basal tractions continue to act on the plate as it dives into the mantle (although perhaps to a greater extent acting on both the under and upper side of the slab).
Lately, the convection theory has been much debated, as modern techniques based on 3D seismic tomography still fail to recognize these predicted large scale convection cells. [ citation needed ] Alternative views have been proposed.
In the theory of plume tectonics followed by numerous researchers during the 1990s, a modified concept of mantle convection currents is used. It asserts that super plumes rise from the deeper mantle and are the drivers or substitutes of the major convection cells. These ideas find their roots in the early 1930s in the works of Beloussov and van Bemmelen, which were initially opposed to plate tectonics and placed the mechanism in a fixistic frame of verticalistic movements. Van Bemmelen later on modulated on the concept in his "Undulation Models" and used it as the driving force for horizontal movements, invoking gravitational forces away from the regional crustal doming.   The theories find resonance in the modern theories which envisage hot spots or mantle plumes which remain fixed and are overridden by oceanic and continental lithosphere plates over time and leave their traces in the geological record (though these phenomena are not invoked as real driving mechanisms, but rather as modulators). The mechanism is still advocated to explain the break-up of supercontinents during specific geological epochs.  It has followers   amongst the scientists involved in the theory of Earth expansion. 
Another theory is that the mantle flows neither in cells nor large plumes but rather as a series of channels just below the Earth's crust, which then provide basal friction to the lithosphere. This theory, called "surge tectonics", was popularized during the 1980s and 1990s.  Recent research, based on three-dimensional computer modeling, suggests that plate geometry is governed by a feedback between mantle convection patterns and the strength of the lithosphere. 
Driving forces related to gravity
Forces related to gravity are invoked as secondary phenomena within the framework of a more general driving mechanism such as the various forms of mantle dynamics described above. In moderns views, gravity is invoked as the major driving force, through slab pull along subduction zones.
Gravitational sliding away from a spreading ridge: According to many authors, [ clarification needed ] plate motion is driven by the higher elevation of plates at ocean ridges.   As oceanic lithosphere is formed at spreading ridges from hot mantle material, it gradually cools and thickens with age (and thus adds distance from the ridge). Cool oceanic lithosphere is significantly denser than the hot mantle material from which it is derived and so with increasing thickness it gradually subsides into the mantle to compensate the greater load. The result is a slight lateral incline with increased distance from the ridge axis.
This force is regarded as a secondary force and is often referred to as "ridge push". This is a misnomer as nothing is "pushing" horizontally and tensional features are dominant along ridges. It is more accurate to refer to this mechanism as gravitational sliding as variable topography across the totality of the plate can vary considerably and the topography of spreading ridges is only the most prominent feature. Other mechanisms generating this gravitational secondary force include flexural bulging of the lithosphere before it dives underneath an adjacent plate which produces a clear topographical feature that can offset, or at least affect, the influence of topographical ocean ridges, and mantle plumes and hot spots, which are postulated to impinge on the underside of tectonic plates.
Slab-pull: Current scientific opinion is that the asthenosphere is insufficiently competent or rigid to directly cause motion by friction along the base of the lithosphere. Slab pull is therefore most widely thought to be the greatest force acting on the plates. In this current understanding, plate motion is mostly driven by the weight of cold, dense plates sinking into the mantle at trenches.  Recent models indicate that trench suction plays an important role as well. However, the fact that the North American Plate is nowhere being subducted, although it is in motion, presents a problem. The same holds for the African, Eurasian, and Antarctic plates.
Gravitational sliding away from mantle doming: According to older theories, one of the driving mechanisms of the plates is the existence of large scale asthenosphere/mantle domes which cause the gravitational sliding of lithosphere plates away from them (see the paragraph on Mantle Mechanisms). This gravitational sliding represents a secondary phenomenon of this basically vertically oriented mechanism. It finds its roots in the Undation Model of van Bemmelen. This can act on various scales, from the small scale of one island arc up to the larger scale of an entire ocean basin.   
Driving forces related to Earth rotation
Alfred Wegener, being a meteorologist, had proposed tidal forces and centrifugal forces as the main driving mechanisms behind continental drift however, these forces were considered far too small to cause continental motion as the concept was of continents plowing through oceanic crust.  Therefore, Wegener later changed his position and asserted that convection currents are the main driving force of plate tectonics in the last edition of his book in 1929.
However, in the plate tectonics context (accepted since the seafloor spreading proposals of Heezen, Hess, Dietz, Morley, Vine, and Matthews (see below) during the early 1960s), the oceanic crust is suggested to be in motion with the continents which caused the proposals related to Earth rotation to be reconsidered. In more recent literature, these driving forces are:
- Tidal drag due to the gravitational force the Moon (and the Sun) exerts on the crust of the Earth
- Global deformation of the geoid due to small displacements of the rotational pole with respect to the Earth's crust
- Other smaller deformation effects of the crust due to wobbles and spin movements of the Earth rotation on a smaller time scale
Forces that are small and generally negligible are:
For these mechanisms to be overall valid, systematic relationships should exist all over the globe between the orientation and kinematics of deformation and the geographical latitudinal and longitudinal grid of the Earth itself. Ironically, these systematic relations studies in the second half of the nineteenth century and the first half of the twentieth century underline exactly the opposite: that the plates had not moved in time, that the deformation grid was fixed with respect to the Earth equator and axis, and that gravitational driving forces were generally acting vertically and caused only local horizontal movements (the so-called pre-plate tectonic, "fixist theories"). Later studies (discussed below on this page), therefore, invoked many of the relationships recognized during this pre-plate tectonics period to support their theories (see the anticipations and reviews in the work of van Dijk and collaborators). 
Of the many forces discussed in this paragraph, tidal force is still highly debated and defended as a possible principal driving force of plate tectonics. The other forces are only used in global geodynamic models not using plate tectonics concepts (therefore beyond the discussions treated in this section) or proposed as minor modulations within the overall plate tectonics model.
In 1973, George W. Moore  of the USGS and R. C. Bostrom  presented evidence for a general westward drift of the Earth's lithosphere with respect to the mantle. He concluded that tidal forces (the tidal lag or "friction") caused by the Earth's rotation and the forces acting upon it by the Moon are a driving force for plate tectonics. As the Earth spins eastward beneath the moon, the moon's gravity ever so slightly pulls the Earth's surface layer back westward, just as proposed by Alfred Wegener (see above). In a more recent 2006 study,  scientists reviewed and advocated these earlier proposed ideas. It has also been suggested recently in Lovett (2006) that this observation may also explain why Venus and Mars have no plate tectonics, as Venus has no moon and Mars' moons are too small to have significant tidal effects on the planet. In a recent paper,  it was suggested that, on the other hand, it can easily be observed that many plates are moving north and eastward, and that the dominantly westward motion of the Pacific Ocean basins derives simply from the eastward bias of the Pacific spreading center (which is not a predicted manifestation of such lunar forces). In the same paper the authors admit, however, that relative to the lower mantle, there is a slight westward component in the motions of all the plates. They demonstrated though that the westward drift, seen only for the past 30 Ma, is attributed to the increased dominance of the steadily growing and accelerating Pacific plate. The debate is still open.
Relative significance of each driving force mechanism
The vector of a plate's motion is a function of all the forces acting on the plate however, therein lies the problem regarding the degree to which each process contributes to the overall motion of each tectonic plate.
The diversity of geodynamic settings and the properties of each plate result from the impact of the various processes actively driving each individual plate. One method of dealing with this problem is to consider the relative rate at which each plate is moving as well as the evidence related to the significance of each process to the overall driving force on the plate.
One of the most significant correlations discovered to date is that lithospheric plates attached to downgoing (subducting) plates move much faster than plates not attached to subducting plates. The Pacific plate, for instance, is essentially surrounded by zones of subduction (the so-called Ring of Fire) and moves much faster than the plates of the Atlantic basin, which are attached (perhaps one could say 'welded') to adjacent continents instead of subducting plates. It is thus thought that forces associated with the downgoing plate (slab pull and slab suction) are the driving forces which determine the motion of plates, except for those plates which are not being subducted.  This view however has been contradicted by a recent study which found that the actual motions of the Pacific Plate and other plates associated with the East Pacific Rise do not correlate mainly with either slab pull or slab push, but rather with a mantle convection upwelling whose horizontal spreading along the bases of the various plates drives them along via viscosity-related traction forces.  The driving forces of plate motion continue to be active subjects of on-going research within geophysics and tectonophysics.
Around the start of the twentieth century, various theorists unsuccessfully attempted to explain the many geographical, geological, and biological continuities between continents. In 1912 the meteorologist Alfred Wegener described what he called continental drift, an idea that culminated fifty years later in the modern theory of plate tectonics. 
Wegener expanded his theory in his 1915 book The Origin of Continents and Oceans.  Starting from the idea (also expressed by his forerunners) that the present continents once formed a single land mass (later called Pangea), Wegener suggested that these separated and drifted apart, likening them to "icebergs" of low density granite floating on a sea of denser basalt.  Supporting evidence for the idea came from the dove-tailing outlines of South America's east coast and Africa's west coast, and from the matching of the rock formations along these edges. Confirmation of their previous contiguous nature also came from the fossil plants Glossopteris and Gangamopteris, and the therapsid or mammal-like reptile Lystrosaurus, all widely distributed over South America, Africa, Antarctica, India, and Australia. The evidence for such an erstwhile joining of these continents was patent to field geologists working in the southern hemisphere. The South African Alex du Toit put together a mass of such information in his 1937 publication Our Wandering Continents, and went further than Wegener in recognising the strong links between the Gondwana fragments.
Wegener's work was initially not widely accepted, in part due to a lack of detailed evidence. The Earth might have a solid crust and mantle and a liquid core, but there seemed to be no way that portions of the crust could move around. Distinguished scientists, such as Harold Jeffreys and Charles Schuchert, were outspoken critics of continental drift.
Despite much opposition, the view of continental drift gained support and a lively debate started between "drifters" or "mobilists" (proponents of the theory) and "fixists" (opponents). During the 1920s, 1930s and 1940s, the former reached important milestones proposing that convection currents might have driven the plate movements, and that spreading may have occurred below the sea within the oceanic crust. Concepts close to the elements now incorporated in plate tectonics were proposed by geophysicists and geologists (both fixists and mobilists) like Vening-Meinesz, Holmes, and Umbgrove.
One of the first pieces of geophysical evidence that was used to support the movement of lithospheric plates came from paleomagnetism. This is based on the fact that rocks of different ages show a variable magnetic field direction, evidenced by studies since the mid–nineteenth century. The magnetic north and south poles reverse through time, and, especially important in paleotectonic studies, the relative position of the magnetic north pole varies through time. Initially, during the first half of the twentieth century, the latter phenomenon was explained by introducing what was called "polar wander" (see apparent polar wander) (i.e., it was assumed that the north pole location had been shifting through time). An alternative explanation, though, was that the continents had moved (shifted and rotated) relative to the north pole, and each continent, in fact, shows its own "polar wander path". During the late 1950s it was successfully shown on two occasions that these data could show the validity of continental drift: by Keith Runcorn in a paper in 1956,  and by Warren Carey in a symposium held in March 1956. 
The second piece of evidence in support of continental drift came during the late 1950s and early 60s from data on the bathymetry of the deep ocean floors and the nature of the oceanic crust such as magnetic properties and, more generally, with the development of marine geology  which gave evidence for the association of seafloor spreading along the mid-oceanic ridges and magnetic field reversals, published between 1959 and 1963 by Heezen, Dietz, Hess, Mason, Vine & Matthews, and Morley. 
Simultaneous advances in early seismic imaging techniques in and around Wadati–Benioff zones along the trenches bounding many continental margins, together with many other geophysical (e.g. gravimetric) and geological observations, showed how the oceanic crust could disappear into the mantle, providing the mechanism to balance the extension of the ocean basins with shortening along its margins.
All this evidence, both from the ocean floor and from the continental margins, made it clear around 1965 that continental drift was feasible and the theory of plate tectonics, which was defined in a series of papers between 1965 and 1967, was born, with all its extraordinary explanatory and predictive power. The theory revolutionized the Earth sciences, explaining a diverse range of geological phenomena and their implications in other studies such as paleogeography and paleobiology.
In the late 19th and early 20th centuries, geologists assumed that the Earth's major features were fixed, and that most geologic features such as basin development and mountain ranges could be explained by vertical crustal movement, described in what is called the geosynclinal theory. Generally, this was placed in the context of a contracting planet Earth due to heat loss in the course of a relatively short geological time.
It was observed as early as 1596 that the opposite coasts of the Atlantic Ocean—or, more precisely, the edges of the continental shelves—have similar shapes and seem to have once fitted together. 
Since that time many theories were proposed to explain this apparent complementarity, but the assumption of a solid Earth made these various proposals difficult to accept. 
The discovery of radioactivity and its associated heating properties in 1895 prompted a re-examination of the apparent age of the Earth.  This had previously been estimated by its cooling rate under the assumption that the Earth's surface radiated like a black body.  Those calculations had implied that, even if it started at red heat, the Earth would have dropped to its present temperature in a few tens of millions of years. Armed with the knowledge of a new heat source, scientists realized that the Earth would be much older, and that its core was still sufficiently hot to be liquid.
By 1915, after having published a first article in 1912,  Alfred Wegener was making serious arguments for the idea of continental drift in the first edition of The Origin of Continents and Oceans.  In that book (re-issued in four successive editions up to the final one in 1936), he noted how the east coast of South America and the west coast of Africa looked as if they were once attached. Wegener was not the first to note this (Abraham Ortelius, Antonio Snider-Pellegrini, Eduard Suess, Roberto Mantovani and Frank Bursley Taylor preceded him just to mention a few), but he was the first to marshal significant fossil and paleo-topographical and climatological evidence to support this simple observation (and was supported in this by researchers such as Alex du Toit). Furthermore, when the rock strata of the margins of separate continents are very similar it suggests that these rocks were formed in the same way, implying that they were joined initially. For instance, parts of Scotland and Ireland contain rocks very similar to those found in Newfoundland and New Brunswick. Furthermore, the Caledonian Mountains of Europe and parts of the Appalachian Mountains of North America are very similar in structure and lithology.
However, his ideas were not taken seriously by many geologists, who pointed out that there was no apparent mechanism for continental drift. Specifically, they did not see how continental rock could plow through the much denser rock that makes up oceanic crust. Wegener could not explain the force that drove continental drift, and his vindication did not come until after his death in 1930. 
Floating continents, paleomagnetism, and seismicity zones
As it was observed early that although granite existed on continents, seafloor seemed to be composed of denser basalt, the prevailing concept during the first half of the twentieth century was that there were two types of crust, named "sial" (continental type crust) and "sima" (oceanic type crust). Furthermore, it was supposed that a static shell of strata was present under the continents. It therefore looked apparent that a layer of basalt (sial) underlies the continental rocks.
However, based on abnormalities in plumb line deflection by the Andes in Peru, Pierre Bouguer had deduced that less-dense mountains must have a downward projection into the denser layer underneath. The concept that mountains had "roots" was confirmed by George B. Airy a hundred years later, during study of Himalayan gravitation, and seismic studies detected corresponding density variations. Therefore, by the mid-1950s, the question remained unresolved as to whether mountain roots were clenched in surrounding basalt or were floating on it like an iceberg.
During the 20th century, improvements in and greater use of seismic instruments such as seismographs enabled scientists to learn that earthquakes tend to be concentrated in specific areas, most notably along the oceanic trenches and spreading ridges. By the late 1920s, seismologists were beginning to identify several prominent earthquake zones parallel to the trenches that typically were inclined 40–60° from the horizontal and extended several hundred kilometers into the Earth. These zones later became known as Wadati–Benioff zones, or simply Benioff zones, in honor of the seismologists who first recognized them, Kiyoo Wadati of Japan and Hugo Benioff of the United States. The study of global seismicity greatly advanced in the 1960s with the establishment of the Worldwide Standardized Seismograph Network (WWSSN)  to monitor the compliance of the 1963 treaty banning above-ground testing of nuclear weapons. The much improved data from the WWSSN instruments allowed seismologists to map precisely the zones of earthquake concentration worldwide.
Meanwhile, debates developed around the phenomenon of polar wander. Since the early debates of continental drift, scientists had discussed and used evidence that polar drift had occurred because continents seemed to have moved through different climatic zones during the past. Furthermore, paleomagnetic data had shown that the magnetic pole had also shifted during time. Reasoning in an opposite way, the continents might have shifted and rotated, while the pole remained relatively fixed. The first time the evidence of magnetic polar wander was used to support the movements of continents was in a paper by Keith Runcorn in 1956,  and successive papers by him and his students Ted Irving (who was actually the first to be convinced of the fact that paleomagnetism supported continental drift) and Ken Creer.
This was immediately followed by a symposium in Tasmania in March 1956.  In this symposium, the evidence was used in the theory of an expansion of the global crust. In this hypothesis, the shifting of the continents can be simply explained by a large increase in the size of the Earth since its formation. However, this was unsatisfactory because its supporters could offer no convincing mechanism to produce a significant expansion of the Earth. Certainly there is no evidence that the moon has expanded in the past 3 billion years other work would soon show that the evidence was equally in support of continental drift on a globe with a stable radius.
During the thirties up to the late fifties, works by Vening-Meinesz, Holmes, Umbgrove, and numerous others outlined concepts that were close or nearly identical to modern plate tectonics theory. In particular, the English geologist Arthur Holmes proposed in 1920 that plate junctions might lie beneath the sea, and in 1928 that convection currents within the mantle might be the driving force.  Often, these contributions are forgotten because:
- At the time, continental drift was not accepted.
- Some of these ideas were discussed in the context of abandoned fixistic ideas of a deforming globe without continental drift or an expanding Earth.
- They were published during an episode of extreme political and economic instability that hampered scientific communication.
- Many were published by European scientists and at first not mentioned or given little credit in the papers on sea floor spreading published by the American researchers in the 1960s.
Mid-oceanic ridge spreading and convection
In 1947, a team of scientists led by Maurice Ewing utilizing the Woods Hole Oceanographic Institution's research vessel Atlantis and an array of instruments, confirmed the existence of a rise in the central Atlantic Ocean, and found that the floor of the seabed beneath the layer of sediments consisted of basalt, not the granite which is the main constituent of continents. They also found that the oceanic crust was much thinner than continental crust. All these new findings raised important and intriguing questions. 
The new data that had been collected on the ocean basins also showed particular characteristics regarding the bathymetry. One of the major outcomes of these datasets was that all along the globe, a system of mid-oceanic ridges was detected. An important conclusion was that along this system, new ocean floor was being created, which led to the concept of the "Great Global Rift". This was described in the crucial paper of Bruce Heezen (1960) based on his work with Marie Tharp,  which would trigger a real revolution in thinking. A profound consequence of seafloor spreading is that new crust was, and still is, being continually created along the oceanic ridges. Therefore, Heezen advocated the so-called "expanding Earth" hypothesis of S. Warren Carey (see above). So, still the question remained: how can new crust be continuously added along the oceanic ridges without increasing the size of the Earth? In reality, this question had been solved already by numerous scientists during the forties and the fifties, like Arthur Holmes, Vening-Meinesz, Coates and many others: The crust in excess disappeared along what were called the oceanic trenches, where so-called "subduction" occurred. Therefore, when various scientists during the early 1960s started to reason on the data at their disposal regarding the ocean floor, the pieces of the theory quickly fell into place.
What Gaia is doing
“What Gaia is essentially measuring is how each star moves on the plane of the sky, both because of its own motion through the Milky Way, and because of our constantly shifting perspective as the Earth moves around the Sun,” said El-Badry. “As one might imagine, these measurements get more precise the longer Gaia looks at each star.”
The data he used was based on 34 months of observations, with each of around 1.8 billion stars getting observed about 100 times.
It’s fairly tedious work for the satellite, but the data it gathers is uniquely revealing. What happens to the data is also unique. Unlike many other large science projects, Gaia’s data is made publicly available as soon as it’s ready. “Anyone with an internet connection can get a first-look at the data and have a chance of finding something new,” said El-Badry.
When stars are plotted according to their color and brightness, they fall along a line called the . [+] main sequence, where they spend most of their lives, evolving into red giants and then white dwarfs only at the end of their lives. The previous survey of nearby binary stars found several hundred, whereas the newest atlas contains 1.3 million pairs, allowing astronomers to better understand the evolution of binary stars and stars in general.
Kareem El-Badry, UC Berkeley
How Body Organs Evolved (Not)
A major area of interest of mine is the problems related to the evolution of human body organs and structures, such as the lungs, bone, blood and organ components in humans. So far, my research has produced four articles on this subject and I am working on several more along the same line. A major problem is that hard parts, such as teeth and the skeleton, commonly fossilize, but tissue traits rarely do. Thus, the claim by evolutionists is that we have no evidence of the evolution of body organs and structures because of the preservation problem, not because the evolution of body organs did not occur. It must have occurred according to the orthodox Darwinian worldview. My contention is the existing evidence shows we have no evidence of the evolution of body organs because it never occurred.
Evidence of No Evolution of Body Organs from Existing Life-Forms
My conclusion that body organs and organ components could not have evolved is based on the fact that the organs of living animals display major gaps in organ and structure design. Furthermore, it has been proven extremely difficult to bridge those gaps with viable functional working systems. In addition, the animal has to survive and reproduce during the transition from, for example, gill to a lung respiratory systems. The organ system, therefore, must have been functional during the entire time of its evolution. This problem is illustrated by the fish bladder evolving into a working lung, which is the current theory of lung evolution.
For example, to achieve sexually-reproductive life by evolution, mitosis must evolve into meiosis. As any freshman biology class will tell you, a chasm exists between mitosis and meiosis (see illustration). Sexual reproduction requires meiosis that produces haploid cells containing half the normal number of chromosomes, which is 23 in humans. Evolutionists propose that, after eons of time, mutations in the genes that controlled mitosis evolved mitosis into meiosis. The fact is the evolution of meiosis from mitosis is untenable, like the “What good is half-of-a-wing?” problem. Until the evolution from mitosis to meiosis is complete, life cannot reproduce sexually.
Furthermore, life must simultaneously have both systems of cell division to reproduce sexually. Otherwise it could not reproduce, which would end that gene line. Thus, functional mitosis must not mutate in the somatic cell line, but mitosis genes must mutate into meiosis in the gonadic cell line in order to evolve. The organism cannot reproduce until it has a fully functional meiosis system. Mitosis and meiosis are very different. Mitosis is a glorified straight forward copy machine. In contrast, meiosis is a functional ‘creator’ that produces the potential for the enormous variety of individuals, as seen everywhere in most all forms of life today – including humans.
So serious is the problem of evolving meiosis by chance, that evolutionists almost uniformly ignore it. This dismissive approach is unlike that assumed by Zimmer and Emlen who readily admitted in their popular evolution textbook the following: “Given the functional uniqueness of sexual reproduction at even the most primitive level, what we will see over and over throughout this book is that such an assumed gradual process could not, in actual scientific fact, have happened.” I agree.
But, according to evolutionists, it must have happened! Darwinism requires that all early life reproduced by fission (thus mitosis), and later sexual reproduction evolved, requiring meiosis. All life-forms that reproduce sexually require replicators like meiosis. Sexual reproduction is a prime example of a complex adaption for which a large number of replicator substitutions would be required. Furthermore, meiosis requires a host of other innovations, including transposition, imprinting, epigenetics, genetic crossing over, the topoisomerase mechanism and numerous other complex systems. All these must have evolved according to the Darwinian worldview, none of which have been explained by evolution. even by just-so stories.
An Alleged 550 Million-Year-Old Fossilized Digestive Tract
Several new discoveries are changing the problem of a lack of tissue evidence for organ and structural evolution, such as the discovery of insipient soft tissue in dinosaur bones. One of the latest examples is the discovery of what is claimed to be a 550-million-year fossilized digestive tract. The fossilized digestive tract, uncovered in the Nevada desert, was described by its finders as “a key find in understanding the early history of animals on Earth.” The find was an example of a Cloudina fossil, (see illustration) labeled a late Ediacaran tubular fossil known to have existed on almost every continent. They vary in size from 0.3 to 6.5 mm in diameter, and 8 to 150 mm in length. These fossils consist of a series of stacked vase-like calcite tubes.
The original mineral composition of the tube structure is unknown, but it is likely constructed of high-magnesium calcite. Each cone traps a significant pore space beneath it, and stacks eccentrically into the one below like a series of cups. This results in an external ridged appearance in which the long tube design appears to be semi-flexible.
The tube discussed in the study by researchers at University of North Carolina is curved or sinuous, and its tube walls are 8 to 50 mm thick. A detailed three-dimensional reconstruction reveals that the tubes had an open base. The tube is more accurately described as a lumen. Its design may be one reason for the level of preservation found. The evolutionists claim it is a 550 million-year-old digestive tract. Assuming their dating is correct, it implies that tissues should be found in younger fossils, like 100 million and even 200 million Darwin Years.
Another possibility is that 550-million-old fossil is not nearly that old. The method of dating was not detailed in the papers I reviewed, but was largely based on the current orthodox evolutionary scenario. The problematic circular-dating method is indicated here: The life-forms in the rocks are used to date the rocks, and then these rocks are then used to date those same life-forms in them. The evolutionists claim these are the oldest ‘guts’ ever discovered.
The authors did not discuss the fossil as evidence for evolution, partly because the organism discussed is a comparatively simple structure, but as more organisms are studied using this and other related techniques we can expect more complex organisms will be studied and this research will help us determine which view is correct my view or that of the Darwinists.
One reason for the advancements in soft tissue research is the improvement of a new technology, in this case the technique done in the X-ray Microanalysis lab of Schiffbauer et al., which is called micro-CT imaging. It is able to create digital 3-D images of a fossil’s interior. This technique allows scientists to assess internal features in the lumen of a Cloudina fossil, and then analyze the entire fossil without damaging it.
The three-dimensional image of the internal ‘digestive tract’ of the fossil was limited, but was the first example that showed the internal structure of the Cloudina fossil, potentially showing soft tissue in its remains. It also found that the creature’s anatomical structure is much more worm-like than coral-like. Specifically, the Schiffbauer research team claim they were able to make a “detailed report of internal soft-tissue preservation within cloudinomorph fossils, and, moreover, one of the earliest reports of preserved internal anatomical structures in the fossil record.” Although, as is true of many (if not most) paleontological finds, drawing conclusions especially about soft tissue, are difficult. In the work done by the X-ray Microanalysis lab, Schiffbauer et al, admit there exist
several caveats that should be considered.… First and foremost, some of these features are not uniformly representative across all of the cloudinomorphs—which should serve as a caution toward future attempts to resolve relationships within this morphotypic group. Moreover, at least some of these alleged diagnostic features (or lack thereof) may be taphonomic noise rather than primary biological signal.
“Taphonomic noise” refers to distortions caused by the burial process and, in general, the effects of decay, bioturbation and biomineralization. The authors add another caution, which also is common in paleontological finds when claims about soft tissue are raised, namely “the degree of tube wall biomineralization in addition to the original biomineral chemistry has been met with differing interpretations.” They further add,
To our knowledge, the structures reported herein are not only the first recognizable soft tissues in cloudinomorphs, but also the oldest guts yet described in the fossil record. As such, the Wood Canyon tubular fossil assemblage has provided a unique view into early animal anatomy. Nonetheless, for at least the cautions listed throughout the discussion above, we choose to refrain from shoehorning the cloudinomorphs into any explicit polychaete family. However, it is the sum of their parts—including the external tube structure, internal soft tissues, and presumed behavioral considerations—that may best denote placement amongst the Annelida as the most plausible.
They raise these issues in spite of the fact that cloudinid taxa in general, “including the terminal Ediacaran index fossil Cloudina, are the most well-studied of these Ediacaran tubular forms due to their global palaeogeographical distribution.” Nonetheless, the issue here is that this new technology will ideally help researchers answer some of the questions about the evolution of organs and structures constructed out of tissues that do not normally preserve well in the fossil record, except for bone, teeth and other hard parts.
Micro-CT imaging and related techniques such as functional NMR (fNMR), will no doubt be useful to obtain details of many other biological structures. The cloudinid family is one of the most abundant small shelly fossils with mineralized skeletons in the Precambrian. This protective shell may be one reason why its inner digestive tract tract, if that’s what it representes, was effectively preserved. The next step is to examine the internal structure of other life-forms.
Technological progress, such as the techniques discussed in this paper, promise to open up to examination the internal structure of organ systems remaining in fossils. Thousands of organisms preserved in amber, tar pits and ice, and other methods of tissue preservation may now be evaluated by micro-CT imaging to reveal traits of the internal structure of a wide variety of organisms. This will help open up the door to understanding the changes in organ systems in history, either supporting evolution or not. The Darwinian worldview requires all organs to have evolved from single cells to the complex organ systems observed today in the natural world.
As has repeatedly occurred in the past century, more knowledge has undermined the evolutionary position and supported the creation view. I have been very active in researching two examples. One is the view that 100 useless organs and structures exist in the human body, but which are now all acknowledged to have an important, or at the least, a very useful function. A second example is the claim of poor designs in the human body, which are still touted by some as evidence of evolution. This, too, is now totally refuted by new scientific research. I expect the same result will occur from the study of organ systems.
See also the analysis of the Cloudina fossil by Günter Bechly, “Did cloudinids have the guts to be worms?” at Evolution News.
 Smith, LaGard. 2018. Darwin’s Secret Sex Problem: Exposing Evolution’s Fatal Flaw— The Origin of Sex. WestBow Press, Bloomington, IN, p. 94.
 Zimmer, C. and D.J. Emlen, 2015. Evolution—Making Sense of Life, W. H. Freeman & Company, New York, NY p. 320.
 From Dawkins, R., 1982. The Extended Phenotype, Oxford University Press, New York, NY, 1982, p. 106.
 Scientists find oldest-known fossilized digestive tract — 550 million years. Science News. January 10, 2020. https://www.sciencedaily.com/releases/2020/01/200110110919.htm.
New book by Dr Bergman addresses back pain and many other alleged cases of poor design in the human body.
 Zhuravlev, A.Y., R. A. Wood, and A. M. Penny, 2015. Ediacaran skeletal metazoan interpreted as a lophophorate. Proceedings of the Royal Academy of Science B. p. 282. http://rspb.royalsocietypublishing.org/lookup/doi/10.1098/rspb.2015.1860.
 Stann, Eric. 2020. A gutsy proposition. MU scientists find oldest-known fossilized digestive tract — 550 million years. Mizzou News. University of Missouri, https://news.missouri.edu/2020/a-gutsy-proposition/ January 10.
 Schiffbauer, James, Tara Selly, Sarah M. Jacquet, Rachel A. Merz, Lyle L. Nelson, Michael A. Strange, Yaoping Cai, Emily F. Smith. 2020. Discovery of bilaterian-type through-guts in cloudinomorphs from the terminal Ediacaran Period. Nature Communications, 11 (1) DOI: 10.1038/s41467-019-13882-z.
 Schiffbauer, James, 2020 Bold added to original/
 Selly, Tera and James Schiffbauer. 2019. A New Cloudinid Fossil Assemblage from the Terminal Ediacaran of Nevada, USA. Journal of Systematic Palaeontology. 17(13). https://www.tandfonline.com/doi/full/10.1080/14772019.2019.1623333.
 Bergman, Jerry. 2019. Useless Organs: The Rise and Fall of the Once Major Argument for Evolution. 2019. Tulsa, OK: Bartlett Publishing.
 Bergman, Jerry.2019. The “Poor Design” Argument Against Intelligent Design Falsified. 2019. Tulsa, OK: Bartlett Publishing.
Dr. Jerry Bergman has taught biology, genetics, chemistry, biochemistry, anthropology, geology, and microbiology for over 40 years at several colleges and universities including Bowling Green State University, Medical College of Ohio where he was a research associate in experimental pathology, and The University of Toledo. He is a graduate of the Medical College of Ohio, Wayne State University in Detroit, the University of Toledo, and Bowling Green State University. He has over 1,300 publications in 12 languages and 40 books and monographs. His books and textbooks that include chapters that he authored are in over 1,500 college libraries in 27 countries. So far over 80,000 copies of the 40 books and monographs that he has authored or co-authored are in print. For more articles by Dr Bergman, see his Author Profile.
The Jefferson Paradox
Thomas Jefferson, one of the Founding Fathers of the United States, was an amazing polymath. He set out to create a new system of units which were never adopted. He started by looking at what means nature provided for producing a repeatable unit and, like us, he quickly identified the spinning of the Earth and he used a pendulum that beat at the rate of once per second as his starting point.
Thomas Jefferson had unknowingly connected back into the system from prehistory. The following is true:
1,000 Jefferson Feet = 360 Megalithic Yards
366 Jefferson Furlongs = 1 Megalithic degree of arc of the Earth
366 2 Jefferson Furlongs = The exact circumference of the Earth
This is a case-winning piece of evidence!
What Did Amateur Astronomers Persue in the s and ླྀs and even before?
But my orientation is more in acquiring information through the internet, now. By the time the magazines are published, everything in them is already stale except for some of the astronomy articles, which are aimed more at beginners than for people with a background in astronomy. I suspect there are a lot of people like me, and the magazines are striving to recapture some of the ground they've lost by becoming more popular in orientation.
In my opinion, magazines, to include astronomy magazines will yield to the Internet. That will be a sad day for me. I look at Sky and Telescope on my 10 inch Tablet. It is not nearly as good an experience as holding the magazine in my hands. Often times, the magazine is a double truck where one page spills over into the next. I doubt that I will keep Astronomy and Sky and Telescope (I subscribe to both) should they cease a print option and only offer it in the Internet. The astronomy world is a'changing. For the most part, it is changing for the better. But, I will miss the changes necessitated by progress.
On the other hand, I expect electronic reading will continue to improve rapidly. 10 years ago it was excruciating and now it's tolerable. 10 years from now it may be as easy as reading paper (or maybe we'll just get used to it).
#52 Glen A W
Interestingly enough, it seems that astronomy is not only the first science, it may be the last science to which amateurs actively contribute.
For amateur astronomers with the means (e.g., as in the U.S) I suspect there remains a thin possibility of contribution to the discovery of supernovas, perhaps (a long shot) discovery of planets outside our solar system (The dimming methods appears to work with relatively small apertures--16"ish inches.), and I'd think dynamic phenomena on the moon and planets (a few others areas?).
If someone chooses to define amateur astronomy with respect to the proportions of people actively engaged in making productive--real--contributions to science, that is fine by me. Science is beautiful and if regular citizens can still make contributions then I say: fantastic! After all, astronomy is "the branch of science that deals with celestial objects, space, and the physical universe as a whole." (google says so). I don't see why justification for astronomy as aesthetic star-gazing (in which I include myself) needs to be vehment.
It's no thin possibility - you can take up the supernova search any time you want. I know fellows who are doing it tonight. It seems most popular in Japan.
I attended a conference where a fellow was showing evidence of exoplanet transits gathered with only a DSLR and a lens of about 250mm. I believe his method wouldn't find anything that hasn't been found. Still, there is plenty of room in this for amateurs to try. Every C-11 or C-14 out there is a potential research instrument. Those Celestron catalogs weren't making that up.
The biggest reason amateurs can't contribute is lack of skill and organization. The equipment people have is capable of a great many useful things, such as photometry, astrometry, and even limited spectroscopy. But people don't have the skill, or they don't want to do everyday things which contribute incrementally.
In the professional world some smaller scopes which are perfectly usable are not being used. The everyday monitoring of the sky is not exciting enough and it's not good for the career, either.
Edited by Glen A W, 02 April 2015 - 10:22 AM.
Quoting: "The biggest reason amateurs can't contribute is lack of skill and organization. The equipment people have is capable of a great many useful things, such as photometry, astrometry, and even limited spectroscopy. But people don't have the skill, or they don't want to do everyday things which contribute incrementally.
In the professional world some smaller scopes which are perfectly usable are not being used. The everyday monitoring of the sky is not exciting enough and it's not good for the career, either."
A lot of truth here. But another big problem is weather. Professional observatories aren't simply bigger and better equipment they're located where there is an expectation of many clear nights and great seeing. Yes, I could search for supernova with my equipment. But searching two or three times per month really limits one's chances. Yes, that is somewhat of an excuse. But in a very real sense, while my equipment can compete, my weather can't.
I guess I come down in both camps, if you will. I agree with Brooks, there is some great equipment out there that could be used to do "serious" (really, that's a terrible word) work. "Serious work" should be taken to mean: "gathering useful data". Many more amateurs could do this than currently are. I contribute planetary images to several organizations. But it's been quite meager this year as the number of nights I can be out is few and the seeing has been poor.
It's also true, I think, that the pros overlook what modern amateur equipment can do. Do any major observatories have smaller equipment mounted? It seems like the cost would be a drop in the bucket. A roll off roof with 5 C14s automated could do amazing work and sit quite nicely next to the big guns.
Anyway, it would be cool if more amateurs gathered useful data while they're out. They don't have to, of course, but it would be cool.
I thought this thread was about what amateurs USED to do in the 50s and 60s?
I thought this thread was about what amateurs USED to do in the 50s and 60s?
These threads have been known to mutate and take on a life of their own.
It's Devolution I tells Ya!
So I joined this late but have one or two thoughts on the original topic.
The energy and feel of amateur astronomy was very different in the 50's and 60's. There was a much bigger culture of building (or assembling) your own scopes which we inherited from the previous generation.
The skies were seen as an unknown frontier full of awe and mystery at the dawn of the space age.
Scopes were much more modest. A six inch reflector was still hot stuff. I can remember our high school astronomy club meeting near the shore of lake erie one summer night in 1965 and seeing M13 for the first time. I will never forget that view.
Generally it was much harder to find things in those days as most used star hops to do so. Lots of trial and error. When you did locate a DSO it was a victory in itself just to do so.
It was a time when paper and pencil science was still sought after and viable from variable stars to ALPO sketching of lunar and planetary observations.
The hobby was more insular and isolated - hard to find fellow travelers in an era with no internet, no smart phones, much fewer cars (lots of families did not have one), etc.
I would maintain that given the larger context, what we observed was a simpler subset of what folks observe now, but what we SAW was also different. M13 in 1966 was a different experience than M13 in 2015. The tidal wave of incredible amateur and professional images that has emerged since then (especially in the past decade) shapes this in ways that would only make sense if you lived when such images were not as common or spectacular.
In short, we found fewer objects, worked harder to find them and were more impressed when we did.
That's not a criticism - just an observation.
#58 David Gray
I assumed this thread is from a USA perspective – even so I give here some impressions we got from this side of the Atlantic.
I came into Astronomy, turning 17, in the spring of 1961. My first scope a 3” f/13.3 refractor, then in 1964 a 10” f/8 Newtonian which I used for DSO, VS, and also to submit observations to the BAA planetary sections until 1978. Continuing this 1978 to present with a 16.3” f/16 Dall-Kirkham (on the 10” mount). All three of these have proven excellent and the 3” rides as a finder on the D-K and still gives very sharp views when used as a scope in its own right with powers up to even >320x – the 10” OTA is mothballed..
I started subscribing to Sky & Tel. in 1962 September and I do recall being quite envious of what was advertised to amateurs in the US. Also it seemed that more frequent good observing conditions were pretty much countrywide there. Or was it “the grass is greener syndrome”…! Having said that I will point out that the so termed “notoriously cloudy UK” is not as bad as some (also on CN!) describe with their long-distance assumptions. If they believe that then perhaps it might seem incredible that we spent so much time and money on the hobby over the years.
However speaking from that viewpoint and looking through 1960s BAA Journals at some of the observing section reports it is immediately apparent that a 6” scope was no big deal.
It seems that 1960s Journal print is incompatible with present day scanners as the OCR was a mess. Thus I have resorted to a straight scan of the Saturn 1967/68 Report and attached here as a typical example of scopes in use.
Looks to me that 8” and up were not uncommon leaving out such as the ( ** ) 12” Cambridge Uni. (Northumberland Refractor), the 18” London Uni. (Mill Hill) refractor and of course the Arizona LPL(?) 61” reflector. Note that “Spec.” (Speculum) is the antiquated term for reflector still in use back then – most of these would have been Newtonians I would guess.
Back in 1962/63, when I felt the need of something >8”, prices looked pretty steep. Then along came Dudley Fuller (Fullerscopes) with his Unit Purchase Plan were he supplied a scope with whatever basic components you requested. At the point of completion (1964 June) he sent a letter informing me I had a formidable (10”) scope, quarter-ton mount and all, for £150 (c. $420 back then).
Scientists describe how solar system could have formed in bubble around giant star
Despite the many impressive discoveries humans have made about the universe, scientists are still unsure about the birth story of our solar system.
Scientists with the University of Chicago have laid out a comprehensive theory for how our solar system could have formed in the wind-blown bubbles around a giant, long-dead star. Published Dec. 22 in the Astrophysical Journal, the study addresses a nagging cosmic mystery about the abundance of two elements in our solar system compared to the rest of the galaxy.
The general prevailing theory is that our solar system formed billions of years ago near a supernova. But the new scenario instead begins with a giant type of star called a Wolf-Rayet star, which is more than 40 to 50 times the size of our own sun. They burn the hottest of all stars, producing tons of elements which are flung off the surface in an intense stellar wind. As the Wolf-Rayet star sheds its mass, the stellar wind plows through the material that was around it, forming a bubble structure with a dense shell.
"The shell of such a bubble is a good place to produce stars," because dust and gas become trapped inside where they can condense into stars, said coauthor Nicolas Dauphas, professor in the Department of Geophysical Sciences. The authors estimate that 1 percent to 16 percent of all sun-like stars could be formed in such stellar nurseries.
This setup differs from the supernova hypothesis in order to make sense of two isotopes that occur in strange proportions in the early solar system, compared to the rest of the galaxy. Meteorites left over from the early solar system tell us there was a lot of aluminium-26. In addition, studies, including a 2015 one by Dauphas and a former student, increasingly suggest we had less of the isotope iron-60.
This brings scientists up short, because supernovae produce both isotopes. "It begs the question of why one was injected into the solar system and the other was not," said coauthor Vikram Dwarkadas, a research associate professor in Astronomy and Astrophysics.
This brought them to Wolf-Rayet stars, which release lots of aluminium-26, but no iron-60.
"The idea is that aluminum-26 flung from the Wolf-Rayet star is carried outwards on grains of dust formed around the star. These grains have enough momentum to punch through one side of the shell, where they are mostly destroyed -- trapping the aluminum inside the shell," Dwarkadas said. Eventually, part of the shell collapses inward due to gravity, forming our solar system.
As for the fate of the giant Wolf-Rayet star that sheltered us: Its life ended long ago, likely in a supernova explosion or a direct collapse to a black hole. A direct collapse to a black hole would produce little iron-60 if it was a supernova, the iron-60 created in the explosion may not have penetrated the bubble walls, or was distributed unequally.
Other authors on the paper included UChicago undergraduate student Peter Boyajian and Michael Bojazi and Brad Meyer of Clemson University.
How accurately could late 50s - early 60s humans have mapped the solar system? - Astronomy
National Aeronautics and Space Administration
NASA History Division
A CHRONOLOGY OF DEFINING EVENTS IN
1 Oct. 1958 On this date the National Aeronautics and Space Administration began operation. At the time it consisted of only about 8,000 employees and an annual budget of $100 million. In addition to a small headquarters staff in Washington that directed operations, NASA had at the time three major research laboratories inherited from the National Advisory Committee for Aeronautics-the Langley Aeronautical Laboratory established in 1918, the Ames Aeronautical Laboratory activated near San Francisco in 1940, and the Lewis Flight Propulsion Laboratory built at Cleveland, Ohio, in 1941-and two small test facilities, one for high-speed flight research at Muroc Dry Lake in the high desert of California and one for sounding rockets at Wallops Island, Virginia. It soon added several other government research organizations.
11 Oct. 1958 Pioneer I : First NASA launch.
7 Nov. 1958 NASA research pilot John McKay made the last flight in the X-1E, the final model flown of the X-1 series. The various models of the X-1, together with the D-558-I and -II, the X-2, X-3, X-4, X-5, and XF-92A, provided data to correlate test results from the slotted throat wind tunnel at the Langley Aeronautical Laboratory (now NASA's Langley Research Center) with actual flight values. Together, results of flight research and wind tunnel testing enabled the U.S. aeronautical community to solve many of the problems that occur in the transonic speed range (0.7 to 1.3 times the speed of sound). The flight research investigated flight loads, buffeting, aeroelastic effects, pitch-up, instability, longitudinal control, and the effects of wing sweep, contributing to design principles that enabled reliable and routine flight of such aircraft as the century series of fighters (F-100, F-102, F-104, etc.). It contributed equally to the development of all commercial transport aircraft from the mid-1950s to the present.
6 Dec. 1958 The United States launched Pioneer 3 , the first U.S. satellite to ascend to an altitude of 63,580 miles.
18 Dec. 1958 An Air Force Atlas booster placed into orbit a communications relay satellite, PROJECT SCORE or the "talking atlas." A total of 8,750 pounds was placed in orbit, of which 150 pounds was the payload. On 19 Dec. President Eisenhower's Christmas message was beamed from the PROJECT SCORE satellite in orbit, the first voice sent from space.
17 Feb. 1959 The United States launched Vanguard 2 , the first successful launch of this principal IGY scientific satellite.
28 Feb. 1959 The liquid-hydrogen Thor first stage, and an Agena upper stage, both originally developed by the U.S. Air Force, were used by NASA to launch Discoverer 1 , a reconnaissance satellite for the Air Force on 28 Feb.
3 Mar. 1959 The United States sent Pioneer 4 to the Moon, successfully making the first U.S. lunar flyby.
9 Apr. 1959 After a two month selection process, on this date NASA unveiled the Mercury astronaut corps. NASA Administrator T. Keith Glennan publicly introduced the astronauts in a press conference in Washington. The seven men-from the Marine Corps, Lt. Col. John H. Glenn, Jr. (1921- ) from the Navy, Lt. Cdr. Walter M. Schirra, Jr. (1923- ), Lt. Cdr. Alan B. Shepard, Jr. (1923- ), and Lt. M. Scott Carpenter (1925- ) and from the Air Force, Capt. L. Gordon Cooper (1927- ), Capt. Virgil I. "Gus" Grissom (1926-1967), and Capt. Donald K. Slayton (1924-1993)-became heroes in the eyes of the American public almost immediately.
28 May 1959 The United States launches and recovers two monkeys, Able and Baker, after launch in Jupiter nosecone during a suborbital flight. The flight is successful, testing the capability to launch from Cape Canaveral, Florida, and to recover spacecraft in the Atlantic Ocean, but Able later died.
8 Jun. 1959 North American Aviation, Inc. research pilot Scott Crossfield made the first unpowered glide flight in the joint X-15 hypersonic research program NASA conducted with the Air Force, the Navy, and North American. The program completed its 199th and final flight on 24 October 1968 in what many consider to have been the most successful flight research effort in history. It resulted in more than 765 research reports and provided significant data in a variety of hypersonic disciplines ranging from aircraft performance, stability and control, aerodynamic heating, the use of heat-resistant materials, shock interaction, and use of reaction controls. This data led to improved design tools for future hypersonic vehicles and contributed in important ways to the development of the Space Shuttle, including information from flights to the edge of space and back in 1961-1963. Data from these flights were important in designing the Shuttle's reentry flight profile. Also involved in the X-15 research was the development of energy management techniques for the return of the vehicle to its landing site that were essential for the future reentry and horizontal landing of the Shuttle and all future reusable launch vehicles.
1 Apr. 1960 The United States launched TIROS 1 , the first successful meteorological satellite, observing Earth's weather.
13 Apr. 1960 The United States launched Transit 1B , the first experimental orbital navigation system.
1 Jul. 1960 The first launch of the Scout launch vehicle took place on this date. The Scout's four-stage booster could place a 330 pound satellite into orbit, and it quickly became a workhorse in orbiting scientific payloads during the 1960s.
1 Jul. 1960 On this date the Army Ballistic Missile Agency of the Redstone Arsenal, Huntsville, Alabama, formally became a part of NASA and was renamed the George C. Marshall Space Flight Center. This organization included the German "rocket team" led by Wernher von Braun that came to the United States at the conclusion of World War II. This group had been instrumental in building the V-2 rocket, the world's first operational long-range ballistic missile.
12 Aug. 1960 NASA successfully orbited Echo 1 , a 100-foot inflatable, aluminized balloon passive communications satellite. The objective was to bounce radio beams off the satellite as a means of long-distance communications. This effort, though successful, was quickly superseded be active-repeater communications satellites such as Telstar.
19 Dec. 1960 NASA launched Mercury 1 , the first Mercury-Redstone capsule-launch vehicle combination. This was an unoccupied test flight.
31 Jan. 1961 NASA launched Mercury 2 , a test mission of the Mercury-Redstone capsule-launch vehicle combination with the chimpanzee Ham aboard during a 16 1/2 minute flight in suborbital space. Ham and his capsule is successfully recovered.
5 May 1961 Freedom 7 , the first piloted Mercury spacecraft (No. 7) carrying Astronaut Alan B. Shepard, Jr., was launched from Cape Canaveral by MercuryRedstone (MRۅ) launch vehicle, to an altitude of 115 nautical miles and a range of 302 miles. It was the first American space flight involving human beings, and during his 15-minute suborbital flight, Shepard rode a Redstone booster to a splashdown in the Atlantic Ocean. Shepard demonstrated that individuals can control a vehicle during weightlessness and high G stresses, and significant scientific biomedical data were acquired. He reached a speed of 5,100 miles per hour and his flight lasted 14.8 minutes. Shepard was the second human and the first American to fly in space.
25 May 1961 President John F. Kennedy unveiled the commitment to execute Project Apollo on this date in a speech on "Urgent National Needs," billed as a second State of the Union message. He told Congress that the U.S. faced extraordinary challenges and needed to respond extraordinarily. In announcing the lunar landing commitment he said: "I believe this Nation should commitment itself to achieving the goal, before this decade is out, of landing a man on the moon and returning him safely to earth. No single space project in this period will be more impressive to mankind, or more important for the long-range exploration of space and none will be so difficult or expensive to accomplish."
21 Jul. 1961 The second piloted flight of a Mercury spacecraft took place on this date when astronaut "Gus" Grissom undertook a sub-orbital mission. The flight had problems. The hatch blew off prematurely from the Mercury capsule, Liberty Bell 7 , and it sank into the Atlantic Ocean before it could be recovered. In the process the astronaut nearly drowned before being hoisted to safety in a helicopter. These suborbital flights, however, proved valuable for NASA technicians who found ways to solve or work around literally thousands of obstacles to successful space flight.
23 Aug. 1961 NASA launched Ranger 1 on this date, with the mission of photographing and mapping part of the Moon's surface, but it failed to achieve its planned orbit.
19 Sep. 1961 NASA Administrator James E. Webb announced on this date that the site of the NASA center dedicated to human space flight would be Houston, Texas. This became the Manned Spacecraft Center, renamed the Lyndon B. Johnson Space Center in 1973.
25 Oct. 1961 On this date NASA announced the establishment on a deep south bayou the Mississippi Test Facility, renamed the John C. Stennis Space Center in 1988. This installation became the test site for the large Saturn boosters developed for Project Apollo.
27 Oct. 1961 NASA accomplished the first successful test of the Saturn I rocket.
21 Nov. 1961 On this date the Air Force launched a Titan ICBM from Cape Canaveral carrying target nose cone to be used in NikeZeus antimissilemissile tests. This was first Titan ICBM to be fired from Cape Canaveral by a military crew, the 6555th Aerospace Test Wing. The Titan rocket became a standard launch vehicle for the United States in the years that followed, going through several modifications to make it more reliable and capable.
20 Feb. 1962 John Glenn became the first American to circle the Earth, making three orbits in his Friendship 7 Mercury spacecraft. Despite some problems with spacecraft-Glenn flew parts of the last two orbits manually because of an autopilot failure and left his normally jettisoned retrorocket pack attached to his capsule during reentry because of a loose heat shield-this flight was enormously successful. The public, more than celebrating the technological success, embraced Glenn as a personification of heroism and dignity. Among other engagements, Glenn addressed a joint session of Congress and participated in several ticker-tape parades around the country.
7 Jun. 1962 At an all-day meeting at the Marshall Space Flight Center, NASA leaders met to hash out differences over the method of going to the Moon with Project Apollo, with the debate getting heated at times. The contention was essentially between Earth-orbit versus lunar-orbit rendezvous. After more than six hours of discussion those in favor of Earth-orbit rendezvous finally gave in to the lunar-orbit rendezvous mode, saying that its advocates had demonstrated adequately its feasibility and that any further contention would jeopardize the president's timetable. This cleared the path for the development of the hardware necessary to accomplish the president's goal.
10 Jul. 1962 Telstar l : NASA launch of the first privately built satellite (for communications). First telephone and television signals carried via satellite.
3 Oct. 1962 On this date astronaut Wally Schirra flew six orbits in the Mercury spacecraft Sigma 7 .
14 Dec. 1962 Mariner 2 : First successful planetary flyby (Venus).
15-16 May 1963 The capstone of Project Mercury took place on this date with the flight of astronaut L. Gordon Cooper, who circled the Earth 22 times in 34 hours aboard the Mercury capsule Faith 7 .
22 Aug. 1963 Experimental aircraft X-15 sets altitude record of 354,200 feet (67 miles).
29 Jan. 1964 NASA's largest launch vehicle, Saturn SA-5 , sends a record of 19 tons into orbit during a test flight.
8 Apr. 1964 The first American Gemini flight took place on this date, an unpiloted test that made four orbits and was successfully recovered.
28 May 1964 The United States placed the first Apollo Command Module (CM) in orbit. This Apollo capsule was launched during an automated test flight atop a Saturn I in preparation of the lunar landing program.
28 Jul. 1964 The United States' Ranger 7 sends back to Earth 4,300 close-up images of the Moon before it impacts on the surface.
30 Oct. 1964 NASA pilot Joseph Walker conducted the first flight in the Lunar Landing Research Vehicle (LLRV), known for its unusual shape as the "Flying Bedstead." Two LLRVs and three Lunar Landing Training Vehicles developed from them provided realistic simulation that was critical for landing a spacecraft on the Moon in the Apollo program. The LLRVs also provided the controls design data base for the lunar module.
23 Mar. 1965 Following two unoccupied test flights, the first operational mission- Gemini III- of Project Gemini took place. Former Mercury astronaut Gus Grissom commanded the mission, with John W. Young, a Naval aviator chosen as an astronaut in 1962, accompanying him.
6 Apr. 1965 The United States launched Intelsat I , the first commercial satellite (communications), into geostationary orbit.
3-7 Jun. 1965 The second piloted Gemini mission, Gemini IV , stayed aloft for four days and astronaut Edward H. White II performed the first EVA or spacewalk by an American. This was a critical task that would have to be mastered before landing on the Moon.
14 Jul. 1965 An American space probe, Mariner 4 , flies within 6,118 miles of Mars after an eight month journey. This mission provided the first close-up images of the red planet. The mission had been launched 28 Nov. 1964.
21-29 Aug. 1965 During the flight of Gemini V , American astronauts Gordon Cooper and Pete Conrad set record with an eight day orbital flight.
4-18 Dec. 1965 During the flight of Gemini VII , American astronauts Frank Borman and James A. Lovell set a duration record of fourteen days in Earth-orbit that holds for five years.
15-16 Dec. 1965 During Gemini VI , U.S. astronauts Wally Schirra and Thomas P. Stafford complete the first true space rendezvous by flying within a few feet of Gemini VII .
16 Mar. 1966 During Gemini VIII American astronauts Neil A. Armstrong and David Scott performed the first orbital docking their spacecraft to an Agena target vehicle, becoming the first coupling of two spacecraft. This was a critical task to master before attempting to land on the Moon, a mission that required several dockings and undockings of spacecraft.
3 Apr. 1966 On this date the Soviet Union achieved lunar orbit with its Luna 10 space probe, the first such vehicle to do so. This robotic flight had been launched on 31 Mar. 1966 and it provided scientific data about the Moon to Earth for several weeks.
2 Jun. 1966 On this date Surveyor 1 landed on the Moon and transmitted more than 10,000 high-quality photographs of the surface. This was the first American spacecraft to soft-land on the Moon. It had been launch on 30 May, and it touched down on the "Ocean of Storms," a possible site for the Apollo landings.
3-6 Jul. 1966 During the flight of Gemini IX on this date, American astronauts Tom Stafford and Eugene Cernan make a two-hour EVA.
18-21 Jul. 1966 During Gemini X American astronauts Mike Collins and John Young make two rendezvous and docking maneuvers with Agena target vehicles, plus complete a complex EVA.
10 Aug. 1966-1 Aug. 1967 The Lunar Orbiter project was conducted for a year between these dates. This project, originally not intended to support Apollo, was reconfigured in 1962 and 1963 to further the Kennedy mandate more specifically by mapping the surface. In addition to a powerful camera that could send photographs to Earth tracking stations, it carried three scientific experiments-selnodesy (the lunar equivalent of geodesy), meteoroid detection, and radiation measurement. While the returns from these instruments interested scientists in and of themselves, they were critical to Apollo. NASA launched five Lunar Orbiter satellites, all successfully achieving their objectives.
11-15 Nov. 1966 The last Gemini flight, Gemini XII , was launched on this date. During this mission, American astronauts Jim Lovell and Buzz Aldrin completed three EVAs and a docking with an Agena target vehicle.
27 Jan. 1967 At 6:31 p.m. on this date, during a simulation aboard Apollo-Saturn (AS) 204 on the launch pad at Kennedy Space Center, Florida, after several hours of work, a flash fire broke out in the pure oxygen atmosphere of the capsule and flames engulfed the capsule and the three astronauts aboard-Gus Grissom, Ed White, and Roger Chaffee-died of asphyxiation. Although three other astronauts had been killed before this time-all in plane crashes-these were the first deaths directly attributable to the U.S. space program. As a result of this accident the Apollo program went into hiatus until the spacecraft could be redesigned. The program returned to flight status during Apollo 7 in October 1968.
25 Apr. 1967 Air Force Col. Joseph Cotton and NASA research pilot Fitzhugh Fulton made the first NASA flight in the XB-70A. The 23 NASA flights in the 129-flight joint program with the Air Force investigated the stability and handling qualities of large, delta-wing aircraft flying at high supersonic speeds. Together these flights contributed data for designing future supersonic aircraft in such areas as environmental noise (including sonic booms), potential flight corridors, flight control, operational problems, and clear-air turbulence. It also validated wind tunnel data and revealed drag components not consistent with or not simulated by wind tunnel testing.
3 Oct. 1967 The X-15 experimental rocket plane set a speed record for piloted vehicles by reaching 4,534 mph (mach 6.72) at a 99,000 feet altitude over the Mojave Desert in California. Piloted by Maj. William J. Knight, USAF, the X-15 no. 2 flight undertook experiments to: (1) test Martin ablative coating and ramjet local flow (2) check out stability and control with dummy ramjets and characteristics of external tank separation and (3) conduct fluidic temperature probes. The previous space record of 4,250 mph (mach 6.33) had been set by Maj. Knight on 18 Nov. 1966.
9 Nov. 1967 During Apollo 4 , an unpiloted test of the launcher and spacecraft, NASA proves that the combination could safely reach the Moon.
22 Jan. 1968 In Apollo 5 , NASA made the first flight test of the propulsion systems of the Lunar Module ascent/descent capability.
14 Sep. 1968 In a significant first, the Soviet Union sent its Zond 5 , lunar mission capsule around the Moon and brought it back safely to Earth. This was an unpiloted test of the system.
11-22 Oct. 1968 The first piloted flight of the Apollo spacecraft, Apollo 7 , and Saturn IB launch vehicle, this flight involved astronauts Wally Schirra, Donn F. Eisele, and Walter Cunningham who tested hardware in Earth orbit.
21-27 Dec. 1968 On 21 Dec. 1968, Apollo 8 took off atop a Saturn V booster from the Kennedy Space Center with three astronauts aboard-Frank Borman, James A. Lovell, Jr., and William A. Anders-for a historic mission to orbit the Moon. At first it was planned as a mission to test Apollo hardware in the relatively safe confines of low Earth orbit, but senior engineer George M. Low of the Manned Spacecraft Center at Houston, Texas (renamed the Johnson Space Center in 1973), and Samuel C. Phillips, Apollo Program Manager at NASA headquarters, pressed for approval to make it a circumlunar flight. The advantages of this could be important, both in technical and scientific knowledge gained as well as in a public demonstration of what the U.S. could achieve. In the summer of 1968 Low broached the idea to Phillips, who then carried it to the administrator, and in Nov. the agency reconfigured the mission for a lunar trip. After Apollo 8 made one and a half Earth orbits its third stage began a burn to put the spacecraft on a lunar trajectory. As it traveled outward the crew focused a portable television camera on Earth and for the first time humanity saw its home from afar, a tiny, lovely, and fragile "blue marble" hanging in the blackness of space. When it arrived at the Moon on Christmas Eve this image of Earth was even more strongly reinforced when the crew sent images of the planet back while reading the first part of the Bible-"God created the heavens and the Earth, and the Earth was without form and void"-before sending Christmas greetings to humanity. The next day they fired the boosters for a return flight and "splashed down" in the Pacific Ocean on 27 Dec. It was an enormously significant accomplishment coming at a time when American society was in crisis over Vietnam, race relations, urban problems, and a host of other difficulties. And if only for a few moments the nation united as one to focus on this epochal event. Two more Apollo missions occurred before the climax of the program, but they did little more than confirm that the time had come for a lunar landing.
3-13 Mar. 1969 In Apollo 9 , astronauts James McDivitt, David Scott, and Russell Schweickart orbit the Earth and test all of the hardware needed for a lunar landing.
18-26 May 1969 In Apollo 10 , Eugene Cernan, John Young, and Tom Stafford run the last dress rehearsal for the Moon landing. They take the Lunar Module (LM) for a test run within 10 miles of the lunar surface.
16-24 Jul. 1969 The first lunar landing mission, Apollo 11 lifted off on 16 Jul. 1969, and after confirming that the hardware was working well began the three day trip to the Moon. At 4:18 p.m. EST on 20 Jul. 1969 the LM-with astronauts Neil A. Armstrong and Edwin E. Aldrin-landed on the lunar surface while Michael Collins orbited overhead in the Apollo command module. After checkout, Armstrong set foot on the surface, telling the millions of listeners that it was "one small step for man-one giant leap for mankind." Aldrin soon followed him out and the two plodded around the landing site in the 1/6 lunar gravity, planted an American flag but omitted claiming the land for the U.S. as had routinely been done during European exploration of the Americas, collected soil and rock samples, and set up some experiments. After more than 21 hours on the lunar surface, they returned to Collins on board "Columbia," bringing 20.87 kilograms of lunar samples with them. The two Moonwalkers had left behind scientific instruments, an American flag and other mementos, including a plaque bearing the inscription: "Here Men From Planet Earth First Set Foot Upon the Moon. Jul. 1969 A.D. We came in Peace For All Mankind." The next day they began the return trip to Earth, "splashing down" in the Pacific on 24 Jul.
15 Sep. 1969 The presidentially-appointed Space Task Group issued its report on the post-Apollo space program on this date. Chartered on 13 Feb. 1969 under the chairmanship of Vice President Spiro T. Agnew, this group met throughout the spring and summer to plot a course for the space program. The politics of this effort was intense. NASA lobbied hard with the Group and especially its chair for a far-reaching post-Apollo space program that included development of a space station, a reusable Space Shuttle, a Moon base, and a human expedition to Mars. The NASA position was well reflected in the group's Sep. report, but Nixon did not act on the Group's recommendations. Instead, he was silent on the future of the U.S. space program until a Mar. 1970 statement that said "we must also recognize that many critical problems here on this planet make high priority demands on our attention and our resources."
14-24 Nov. 1969 In Apollo 12 U.S. astronauts Charles Conrad, Richard Gordon, and Alan Bean go to the Moon for second manned landing. They landed near the Surveyor 3 landing sight on 18 Nov. They spend 7.5 hours walking on the surface, including an inspection of the Surveyor probe.
5 Mar. 1970 First NASA flight in a YF-12A with Fitzhugh Fulton as pilot. In a joint program with the Air Force, two YF-12As and a YF-12C were flown 296 times over nine years to explore high-speed, high-altitude flight. The program yielded a wealth of information on thermal stress, aerodynamics, the high-altitude environment, propulsion (including mixed compression inlet research), precision measurement of gust velocity, and flight control systems that will still be useful for designing future vehicles that will fly at three times the speed of sound or faster. It complemented the X-15 program in that it yielded information about sustained flight at Mach 3, whereas the much faster X-15 could only fly for comparatively short periods of time. Since 1990, SR-71 Blackbirds have done follow-on research to the work done by the XB-70 and YF-12s in support of NASA's High Speed Research program. (The SR-71s are similar to the YF-12s but improved by an integrated propulsion/flight control system developed in 1978 on the YF-12 to reduce the occurrence of inlet unstarts.)
11-17 Apr. 1970 The flight of Apollo 13 was one of the near disasters of the Apollo program. At 56 hours into the flight, an oxygen tank in the Apollo service module ruptured and damaged several of the power, electrical, and life support systems. People throughout the world watched and waited and hoped as NASA personnel on the ground and the crew, well on their way to the Moon and with no way of returning until they went around it, worked together to find a way safely home. While NASA engineers quickly determined that sufficient air, water, and electricity did not exist in the Apollo capsule to sustain the three astronauts until they could return to Earth, they found that the LM-a self-contained spacecraft unaffected by the accident-could be used as a "lifeboat" to provide austere life support for the return trip. It was a close-run thing, but the crew returned safely on 17 Apr. 1970. The near disaster served several important purposes for the civil space program-especially prompting reconsideration of the propriety of the whole effort while also solidifying in the popular mind NASA's technological genius.
31 Jan.-9 Feb. 1971 Apollo 14 was the third U.S. lunar landing mission, and the first since the near disaster of Apollo 13 . Alan Shepard and Edgar Mitchell went to the Moon while Stuart Roosa piloted the CM. They perform nine hours of moonwalks and brought back 98 pounds of lunar material.
9 Mar. 1971 NASA research pilot Thomas McMurtry completed the first flight in an F-8A modified with Langley researcher Richard Whitcomb's supercritical wing. The flight research program, which lasted until 1973, demonstrated that Whitcombís design reduced drag and therefore increased the fuel efficiency of an airplane flying in the transonic speed range. The concept is now widely used on commercial and military aircraft throughout the world. Follow-on research with the F-111 Transonic Aircraft Technology (TACT), Highly Maneuverable Aircraft Technology (HiMAT), Advanced Fighter Technology Integration F-16, and X-29 aircraft through the year 1988 has demonstrated the effects of various planforms and sweeps of the supercritical airfoil.
26 Jul.-7 Aug. 1971 The first of the longer, expedition-style lunar landing missions, Apollo 15 was the first to include the lunar rover to extend the range of the astronauts on the Moon. They brought back 173 pounds of moon rocks, including one of the prize artifacts of the Apollo program, a sample of ancient lunar crust called the "Genesis Rock."
13 Nov. 1971 Mariner 9 : The first mission to orbit another planet (Mars).
5 Jan. 1972 NASA Administrator James C. Fletcher met with President Richard M. Nixon at the "Western White House" in San Clemente, California, to discuss the future of the space program and then issued a statement to the media announcing the decision to "proceed at once with the development of an entirely new type of space transportation system designed to help transform the space frontier of the 1970s into familiar territory, easily accessible for human endeavor in the 1980s and '90s." This became the Space Shuttle, first flown in space on 12-14 Apr. 1981.
3 Mar. 1972-Present To prepare the way for a possible mission to the four giant planets of the outer Solar System, Pioneer 10 and Pioneer 11 were launched to Jupiter. Both were small, nuclearpowered, spinstabilized spacecraft that AtlasCentaur launched. The first of these was launched on 3 Mar. 1972, traveled outward to Jupiter, and in May 1991 was about 52 Astronautical Units (AU), roughly twice the distance from Jupiter to the Sun, and still transmitting data. In 1973, NASA launched Pioneer 11 , providing scientists with their closest view of Jupiter, from 26,600 miles above the cloud tops in Dec. 1974.
16-27 Apr. 1972 During Apollo 16 astronauts John Young, Thomas Mattingly II, and Charles Duke make the fifth American landing on the Moon. Young and Duke spend 3 days with the lunar rover near the Descartes crater
25 May 1972 NASA research pilot Gary Krier flew an F-8C modified with an all-electric, digital-fly-by-wire flight control system, kicking off the F-8 Digital Fly-By-Wire (DFBW) program that demonstrated its effectiveness by operating the aircraft without a mechanical back-up system. The F-8 DFBW laid the groundwork for and proved the concept of digital fly-by-wire that is now used in a variety of airplanes ranging from the F/A-18 to the Boeing 777 and the Space Shuttle. More advanced versions of DFBW were also used in the flight control systems of both the X-29 and X-31 research aircraft, which would have been uncontrollable without them.
23 Jul. 1972-Present Landsat 1 was launched from Kennedy Space Center, to perform an Earth resource mapping mission. Initially called the Earth Resources Technology Satellite (ERTS) and later renamed, Landsat 1 changed the way in which Americans looked at the planet. It provided data on vegetation, insect infestations, crop growth, and associated landuse information. Two more Landsat vehicles were launched in Jan. 1975 and Mar. 1978, performed their missions and exited service in the 1980s. Landsat 4 , launched 16 Jul. 1982, and Landsat 5 , launched 1 Mar. 1984, were "second generation" spacecraft, with greater capabilities to produce more detailed land-use data. The system enhanced the ability to develop a worldwide crop forecasting system, to devise a strategy for deploying equipment to contain oil spills, to aid navigation, to monitor pollution, to assist in water management, to site new power plants and pipelines, and to aid in agricultural development.
7-19 Dec. 1972 Apollo 17 was the last of the six Apollo missions to the Moon, and the only one to include a scientist-astronaut/geologist Harrison Schmitt-as a member of the crew. Schmitt and Eugene Cernan, had extended EVAs on the Moon, 22 hours, 4 minutes for each. Ronald Evans piloted the CM.
25 May-22 Jun. 1973 Following the launch of the United States' orbital workshop, Skylab 1 , on 14 May 1973, the Skylab 2 mission began in which astronauts aboard Apollo spacecraft rendezvoused and docked with the orbital workshop. The workshop had developed technical problems due to vibrations during liftoff and the meteoroid shield-designed also to shade Skylab's workshop from the Sun's rays-ripped off, taking with it one of the spacecraft's two solar panels, and another piece wrapped around the other panel keeping it from properly deploying. In spite of this, the space station achieved a nearcircular orbit at the desired altitude of 270 miles. While NASA technicians worked on a solution to the problem, an intensive tenday period followed before the Skylab 2 crew launched to repair the workshop. This crew carried a parasol, tools, and replacement film to repair the orbital workshop. After substantial repairs requiring extravehicular activity (EVA), including deployment of a parasol sunshade that cooled the inside temperatures to 75 degrees Fahrenheit on 4 Jun., by the workshop was habitable. During a 7 Jun. EVA the crew freed the jammed solar array and increased power to the workshop. In orbit the crew conducted solar astronomy and Earth resources experiments, medical studies, and five student experiments. This crew made 404 orbits and carried out experiments for 392 hours, in the process making three EVAs totalling six hours and 20 minutes. The first group of astronauts returned to Earth on 22 Jun. 1973, and two other Skylab missions followed. The first of these, Skylab 3 , was launched using Apollo hardware on 28 Jul. 1973 and its mission lasted 59 days. Skylab 4 , the last mission on the workshop was launched on 16 Nov. 1973 and remained in orbit for 84 days. At the conclusion of Skylab 4 the orbital workshop was powered down for four years.
3 Dec. 1973 Pioneer 10 : The first flyby of Jupiter.
17 May 1974 SMS-A : The launch of the first geosynchronous weather satellite.
1 Sep. 1974 The interplanetary scientific probe Pioneer 11 , launched 5 April 1973, began an encounter with Jupiter that brought it to within three times closer than sister space probe, Pioneer 10 , visiting the planet a year earlier. It also sent back the first polar images of the planet. Because of the successful earlier Pioneer 10 mission, NASA was able to attempt a somewhat more risky approach with this space probe, a clockwise trajectory by the south polar region and then straight back up through the intense inner radiation belt by the equator and back out over Jupiter's north pole. Pioneer 11 closed to its closest point with Jupiter on 3 December, coming within 42,000 km of the surface at a speed of 171,000 kph. This mission gathered data on the planet's magnetic field, measured distributions of high-energy electrons and protons in the radiation belts measured planetary geophysical characteristics, and studied gravity and atmosphere. It then headed on toward a September 1979 encounter with Saturn and eventual departure from the Solar System.
15-24 Jul. 1975 The Apollo-Soyuz Test Project was the first international human space flight, taking place at the height of the détente between the United States and the Soviet Union during the mid-1970s. It was specifically designed to test the compatibility of rendezvous and docking systems for American and Soviet spacecraft, and to open the way for international space rescue as well as future joint missions. To carry out this mission existing American Apollo and Soviet Soyuz spacecraft were used. The Apollo spacecraft was nearly identical to the one that orbited the Moon and later carried astronauts to Skylab, while the Soyuz craft was the primary Soviet vehicle used for cosmonaut flight since its introduction in 1967. A universal docking module was designed and constructed by NASA to serve as an airlock and transfer corridor between the two craft. Astronauts Tom Stafford, Vance D. Brand, and Donald K. Slayton took off from Kennedy Space Center on 15 Jul., to meet the already orbiting Soyuz spacecraft. Some 45 hours later the two craft rendezvoused and docked, and then Apollo and Soyuz crews conducted a variety of experiments over a twoday period. The two spacecraft remained docked for 44 hours, separated, then redocked, separating finally a few hours later. After separation, the Apollo vehicle remained in space an additional six days while Soyuz returned to Earth approximately 43 hours after separation. The flight was more a symbol of the lessening of tensions between the two superpowers than a significant scientific endeavor, a sharp contrast with the competition for international prestige that had fueled much of the space activities of both nations since the late 1950s. This was the last Apollo spacecraft to be flown.
5 Aug. 1975 NASA research pilot John Manke landed the X-24B lifting body on the Edwards Air Force Base runway, demonstrating that a Space Shuttle-like vehicle could be landed safely without a separate power source for landings on a designated runway after returning from orbit. Lasting from 1963 to 1975, the lifting-body program included the M2-F1, M2-F2, M2-F3, HL-10, X-24A, and X-24B wingless lifting vehicles and served as a precursor not only to the Space Shuttle but to the X-33 technology demonstrator for next-generation reusable space vehicles and the X-38 prototype for a crew return vehicle from the international space station.
20 Aug. 1975-21 May 1983 Viking 1 was launched from the Kennedy Space Center, on a trip to Mars. The probe landed on 20 Jul. 1976, on the Chryse Planitia (Golden Plains). Viking 2 was launched for Mars on 9 Nov. 1975 and landed on 3 Sep. 1976. The Viking project's primary mission ended on 15 Nov. 1976, 11 days before Mars' superior conjunction (its passage behind the Sun), although the Viking spacecraft continued to operate for six years after first reaching Mars. Its last transmission reached Earth on 11 Nov. 1982. Controllers at NASA's Jet Propulsion Laboratory tried unsuccessfully for another six and onehalf months to regain contact with the lander, but finally closed down the overall mission on 21 May 1983.
20 Jul. 1976 The Viking 1 planetary lander touched down on this date on the Chryse Planitia (Golden Plains) of Mars after a voyage of nearly one year. The Viking project's primary mission ended on 15 Nov. 1976, although the Viking spacecraft continued to transmit to Earth for six years after first reaching Mars.
18 Feb. 1977 The first Space Shuttle orbiter, Enterprise (OV𪐭)-named for the spacecraft made famous in the "Star Trek" television series after a promotional campaign by "trekkers" such as had never been seen before in space program history-was first flown in flight tests atop the Boeing 747 ferrying aircraft at NASA's Dryden Flight Research Center in southern California. The Enterprise also made its first free flight test at Dryden on 12 August 1977. The fifth and last free test flight of the Enterprise took place on 26 October 1977 with NASA astronauts Fred Haise and Gordon Fullerton at the controls. The captive and free-flight tests demonstrated that the Shuttle could fly attached to the 747, which has served since 1981 as the Shuttle Carrier Aircraft to ferry the Orbiters from Dryden, where they landed for many years, to NASA's launch location at the Kennedy Space Center. The free-flight tests demonstrated that the Shuttle could glide to a landing on a runway, and the last landing uncovered a time delay problem with the Shuttle's flight control system that was corrected in a research program using NASA's F-8 Digital Fly-By-Wire aircraft between 1977 and 1981.
20 Aug. 1977-Present During the latter 1960s NASA scientists found that once every 176 years both the Earth and all the giant planets of the Solar System gather on one side of the Sun. This geometric line-up made possible closeup observation of all the planets in the outer solar system (with the exception of Pluto) in a single flight, the "Grand Tour." NASA launched two of these from Cape Canaveral, Florida: Voyager 2 lifting off on 20 Aug. 1977 and Voyager 1 entering space on a faster, shorter trajectory on 5 Sep. 1977. Both spacecraft were delivered to space aboard TitanCentaur expendable rockets. On Feb. 1979 Voyager 1 entered the Jovian system, its primary objective, yet it took until 5 Mar. 1979 to arc in to the closest point where it could explore the moons Io and Europa. In Jul. 1979 Voyager 2 its sister probe and explored Jupiter's moons. The spacecraft then traveled on to Saturn and in Jul. 1981 Voyager 2 began returning data from Saturn. A critical part of this encounter took place on 26 Aug. 1981 when Voyager 2 emerged from behind Saturn only to find the aiming mechanism was jammed, causing the instruments to be pointed out into space. This was corrected and Voyager 2 remained responsive to Earth-bound controller. Not so Voyager 1 . It went up over the Saturn's orbital plane, never to be seen again. In Sep. 1981 Voyager 2 left Saturn behind. As the mission progressed, with the successful achievement of all its objectives at Jupiter and Saturn in Dec. 1980, additional flybys by Voyager 2 of the two outermost giant planets, Uranus and Neptune, proved possible. In Jan. 1986 Voyager 2 encountered Uranus and in 1989 it encountered Neptune. Eventually, between them, Voyager 1 and Voyager 2 explored all the giant outer planets, 48 of their moons, and the unique systems of rings and magnetic fields those planets possess. In 1993 Voyager 2 also provided the first direct evidence of the long-sought after heliopause-the boundary between our Solar System and interstellar space.
26 Oct. 1977 The fifth and last free test flight of the Space Shuttle Enterprise took place. In that flight the Enterprise encountered control problems at touchdown. While trying to slow the spacecraft for landing the pilot experienced a left roll, corrected for it, and touched down too hard. The Shuttle bounced once and eventually settled down to a longer landing than expected. This "Pilot Induced Oscillation," as it was called, was occasioned by the pilot taking over from an automated system too late and not allowing himself sufficient time to get the "feel" of the craft. It was, fortunately, self-correcting when the pilot relaxed the controls, and the positive result led to a decision to take the Enterprise on to the Marshall Space Flight Center in Huntsville, Alabama, for a series of ground vibration tests.
20 May 1978-9 May 1979 The United States undertook a pugnacious mission to Venus that was intended to capitalize on scientific knowledge gained from the earlier Soviet Venera 9 and Venera 10 probes. It launched Pioneer Venus Orbiter on a mission to Venus on 20 May 1978 and Pioneer Venus 2 on 8 Aug. 1978. The latter mission was to plunge into the atmosphere and return scientific data about the planet before destruction of the vehicle. On 14 Dec. 1978 the Pioneer Venus Orbiter went into orbit around Venus and relayed data until its systems failed. On 9 May 1979 Pioneer Venus 2 sent five separate parts into the atmosphere of Venus at an average speed of 26,100 mph. Before their destruction they relayed scientific data on the climate, chemical makeup, and atmospheric conditions of the planet.
26 Jun. 1978 Seasat-A was launched from Vandenberg Air Force Base, California, by an Atlas-Agena launch vehicle on this date. It was the first satellite to make global observations of the Earth's oceans. Attached to the Atlas-Agena launch vehicle was a sensor module which carried the payload of five microwave instruments and their antennas. The modules were about 21 meters long with a maximum diameter of 1.5 m without appendages deployed and weighed 2,300 kg. In orbit the satellite appeared to stand on end with the sensor and communications antennas pointing toward Earth and the Agena rocket nozzle and solar panels pointing toward space. Seasat-A was stabilized by a momentum wheel/horizon sensing system. The satellite was designed to demonstrate techniques for global monitoring of oceanographic phenomena and features, to provide oceanographic data, and to determine key features of an operational ocean-dynamics monitoring system. The major difference between Seasat-A and previous Earth observation satellites was the use of active and passive microwave sensors to achieve an all-weather capability. After 106 days of returning data, contact with Seasat-A was lost when a short circuit drained all power from its batteries.
14 Aug. 1978 NASA research pilot William Dana flew the first of 27 data flights in an F-15 equipped with a 10-degree cone in an experiment to improve predictions based on wind-tunnel data. This flight research was sponsored by the USAF Arnold Engineering Development Center (AEDC) and conducted by NASA's Dryden Flight Research Center in cooperation with the AEDC. Researchers acquired data on the cone, using the same instrumentation and technique over a wide range of speeds and Reynolds numbers (for scaling of model-test measurements to full-scale vehicles in flight) in 23 wind tunnels and in the F-15. This experiment provided an assessment of flow quality in each of the tunnels as compared to free flight. Thus, it yielded valuable insights for interpreting data from models in individual tunnels and for choosing which tunnels should be used for particular transonic and supersonic tests.
24 Oct. 1978 Nimbus 7 : Launched environmental research satellite with multiple instruments, one that provided the global evidence of Antarctic ozone depletion in the 1980s.
9 May 1979 The United States undertook a pugnacious mission to Venus that was intended to capitalize on scientific knowledge gained from the earlier Soviet Venera 9 and Venera 10 probes. It launched Pioneer Venus Orbiter on a mission to Venus on 20 May 1978 and Pioneer Venus 2 on 8 August 1978. The latter mission was to plunge into the atmosphere and return scientific data about the planet before destruction of the vehicle. On 14 December 1978 the Pioneer Venus Orbiter went into orbit around Venus and relayed data until its systems failed. On 9 May 1979 Pioneer Venus 2 sent five separate parts into the atmosphere of Venus at an average speed of 26,100 mph. Before their destruction they relayed scientific data on the climate, chemical makeup, and atmospheric conditions of the planet.
11 Jul. 1979 Following the final occupied phase of the Skylab mission in 1974, NASA controllers performed some engineering tests of certain Skylab systems, positioned Skylab into a stable attitude and shut down its systems. In the fall of 1977 agency officials determined that Skylab had entered a rapidly decaying orbit-resulting from greater than predicted solar activity-and that it would reenter the Earth's atmosphere within two years. They steered the orbital workshop as best they could so that debris from reentry would fall over oceans and unpopulated areas of the planet. On 11 Jul. 1979, Skylab finally impacted the Earth's surface. The debris dispersion area stretched from the Southeastern Indian Ocean across a sparsely populated section of Western Australia.
24 Jul. 1979 NASA research pilot Thomas McMurtry conducted the first flight of a KC-135 jet cargo/tanker aircraft modified with winglets developed by NASA Langley Research Center's Richard T. Whitcomb. In a joint program with the Air Force, NASA and AF pilots flew the KC-135 to demonstrate fuel efficiencies that could result from the use of the winglets. Whitcomb had tested several designs in Langley's wind tunnels before selecting roughly nine-foot long vertical fins tapering from about two to six feet in width from their tips to the base where they were attached to the airplane's wingtips. The program showed that, as Whitcomb had anticipated, the winglets helped produce a forward thrust in the vortices that typically swirl off the end of the wing, thereby reducing drag. This increased an aircraft's range by as much as seven percent at cruise speeds, resulting in the adoption of the concept by many transport and business aircraft such as the Gulfstream III and IV, the Boeing 747-400, the McDonnell Douglas (now Boeing) MD-11 and C-17.
14 Feb. 1980 Solar Maximum Mission: The first launch/mission to study the Sun in detail, over the course of heavy sunspot activity.
7 Mar. 1980 Research pilot John Manke made several test flights in the Gossamer Albatross, part of a joint Dryden Flight Research Center/Langley Research Center project using humanpowered aircraft to collect data on large lightweight craft. Manke's flights were propelled by pedals on a bicycle-like arrangement that turned the propeller. Manke researched an altitude of 20 feet, and reported that the Albatross was like nothing he had ever flown before.
12 Apr. 1981 Astronauts John W. Young and Robert L. Crippin flew Space Shuttle Columbia on the first flight of the Space Transportation System (STS-1). Columbia , which takes its name from three famous vessels including one of the first U.S. Navy ships to circumnavigate the globe, became the first airplane-like craft to land from orbit for reuse when it touched down at Edwards Air Force Base in southern California at approximately 10:21 a.m. Pacific Standard Time on 14 Apr. after a flight of 2 days, 6 hours and almost 21 minutes. The mission also was the first to employ both liquid- and solid-propellant rocket engines for the launch of a spacecraft carrying humans.
Jun. 1981-Feb. 1983 NASA's Ames-Dryden Flight Research Facility performed flight research in an F-15 jet aircraft with an advanced, digitally controlled engine designed by Pratt & Whitney. Flight evaluation at Dryden and engine tests at NASA's Lewis Research Center led to significant improvements in the operability and performance of the engine. The Digital Electronic Engine Control program demonstrated that the engine achieved stall-free performance throughout the entire F-15 flight envelope, faster throttle response, improved airstart capability, and an increase of 10,000 feet of altitude in afterburner capability. The system also eliminated the need to trim the engine periodically, which would translate to fuel savings and longer life for the engine. The results were impressive enough that the Air Force committed to full-scale development and production of what became the F-100-PW-220/229 engines. In a follow-on program, the Flight Research Facility conceived and tested active engine stall margin control in 1986-1987 on the F-15 Highly Integrated Digital Electronic Control program, leading to engine and airplane performance improvements without adding weight that were used on the F-15E and F-22 airplanes.
11-16 Nov. 1982 The United States launched STS-5, the Space Shuttle Columbia . The highlight of this mission was that the four astronauts aboard deployed two commercial communications satellites.
4-9 Apr. 1983 The United States flew STS-6, the Space Shuttle Challenger . During this mission, the crew deployed the first of three new shuttle launch Tracking and Data Relay Satellites (TDRSS) into geostationary orbit.
18-24 Jun. 1983 Astronauts Robert L. Crippin and Frederick H. Hauck piloted Space Shuttle Challenger (STS-7) on a mission to launch two communications satellites and the reusable Shuttle Pallet Satellite (SPAS 01). Sally K. Ride, one of three mission specialists on the first Shuttle flight with five crewmembers, became the first woman astronaut. Challenger was named after the HMS Challenger , an English research vessel operating from 1872 to 1876.
30 Aug. 1983 Astronauts Richard H. Truly and Daniel C. Brandstein piloted Space Shuttle Challenger (STS-8) on another historic mission, carrying the first black American astronaut, Guion S. Bluford, into space as a mission specialist. The astronauts launched communications satellite Insat 1B into orbit.
28 Nov. 1983 Astronauts John W. Young and Brewster W. Shaw piloted Space Shuttle Columbia (STS-9) on a mission that carried the first non-U.S. astronaut to fly in the U.S. space program, West German Ulf Merbold. Columbia also transported Spacelab 1 , the first flight of this laboratory in space, carrying more than 70 experiments in 5 areas of scientific research: astronomy and solar physics, space plasma physics, atmospheric physics and Earth observations, life sciences, and materials science.
25 Jan. 1984 President Ronald Reagan made an Apollo-like announcement to build a Space Station within a decade as part of the State of the Union Address before Congress. Reagan's decision came after a long internal discussion as to the viability of the station in the national space program.
3-10 Feb. 1984 The flight of STS-41B, the Space Shuttle Challenger , took place. During this mission on 4 Feb. the first unteathered flights by American astronauts took place wearing the Manned Maneuvering Unit (MMU).
6 Apr. 1984 STS-41C: First on-orbit satellite repair mission (Solar Maximum Mission aboard Space Shuttle Challenger) Crippen, Dick Scobee, Terry Hart, George Nelson, James Von Hoften).
30 Aug. 1984 STS-41D: First flight of Space Shuttle Discovery .
15 Dec. 1984-Mar. 1986 An international armada of spacecraft encounter the Comet Halley during its nearest approach to the Earth in 76 years. The Soviet Union launched Vega 1 (14 Dec. 1984) and Vega 2 (21 Dec. 1984), both probes that would encounter Venus and deploy landers on their way to their primary target, Halley's Comet. In 1985 the European Space Agency launched the Giotto probe to intercept Halley's Comet. Vega 1 deployed a lander to Venus on 11 Jun. 1985. Its lander released a balloon as it descended, taking measurements. On 15 Jun. 1985 Vega 2 performed the released a similar balloon. Both Soviet spacecraft continued on their way to Halley's Comet. Vega 1 had its closet encounter with the comet on 6 Mar. 1986, closing to within a distance of 5,525 miles. Three days later, 9 Mar., Vega 2 approached to within 4,991 miles of Halley's Comet. Finally, on 13-14 Mar. 1986 Giotto approached Halley's Comet at about 360 miles.
8 Aug. 1985 STS-51J: First flight of Space Shuttle Atlantis .
3-7 Oct. 1985 In the first Department of Defense-dedicated mission, the Space Shuttle Atlantis (STS-51J) deployed a classified satellite.
24 Jan. 1986-25 Aug. 1989 Voyager 2 encounters Uranus and Neptune.
28 Jan. 1986 The Space Shuttle Challenger, STS-51L, was destroyed and its crew of seven-Francis R. (Dick) Scobee, Michael J. Smith, Judith A. Resnik, Ronald E. McNair, Ellison S. Onizuka, Gregory B. Jarvis, and Christa McAuliffe-was killed, during its launch from the Kennedy Space Center about 11:40 a.m. The explosion occurred 73 seconds into the flight as a result of a leak in one of two Solid Rocket Boosters that ignited the main liquid fuel tank. The crewmembers of the Challenger represented a cross-section of the American population in terms of race, gender, geography, background, and religion. The explosion became one of the most significant events of the 1980s, as billions around the world saw the accident on television and empathized with any one of the seven crewmembers killed. With this accident the Space Shuttle program went into hiatus as investigations, restructuring of management, and technical alterations to systems took place. On 12 May 1986 James C. Fletcher became the NASA Administrator for a second time, having previously served between 1971 and 1977, with the explicit task of overseeing the Agency's recovery from the accident. On 6 June 1986 the Report of the Presidential Commission on the Space Shuttle Challenger Accident was issued. The White House-appointed commission, chaired by former Secretary of State William P. Rogers, was deliberate and thorough and its findings gave as much emphasis to the accident's managerial as to its technical origins. Astronaut Richard H. Truly became the head of NASA's Shuttle program and directed much of the recovery effort. NASA also created the Office of Safety, Reliability, Maintainability, and Quality Assurance in response to findings from the teams investigating the Challenger accident. The return to flight came on 29 September 1988 when STS-26, Discovery, was launched.
15 Aug. 1986 President Ronald Reagan announced that NASA would no longer launch commercial satellites, except those that were shuttle-unique or have national security o foreign policy implications.
15 Aug. 1986 NASA secured Presidential and Congressional support for the acquisition of a replacement orbiter for Challenger . This would enable the Agency to continue its efforts to build the international Space Station.
14 Jul. 1987 NASA submitted to President Ronald Reagan a report on the agency's implementation of the recommendations of the Presidential Commission on the Space Shuttle Challenger Accident.
Dec. 1987 The NASA Lewis Research Center's Advanced Turboprop Project (1976-1987) received the Robert Collier Trophy for outstanding research and development in aerospace activities. It was an ambitious project to return to fuel saving, propeller-driven aircraft. At its height it involved over 40 industrial contracts, 15 university grants, and contracts with all four NASA research centers, Lewis, Langley, Dryden, and Ames. The progress of the advanced turboprop development seemed to foreshadow its future dominance of commercial flight. The project had four technical stages: "concept development" from 1976 to 1978 "enabling technology" from 1978 to 1980 "large scale integration" from 1981 to 1987 and finally "flight research" in 1987. During each of these stages NASA's engineers confronted and solved specific technical problems that were necessary for the advanced turboprop project to meet the defined government objectives concerning safety, efficiency, and environmental protection. NASA Lewis marshaled the resources and support of the United States aeronautical community to bring the development of the new technology to the point of successful flight testing.
29 Sep.-3 Oct. 1988 The twenty-sixth shuttle flight, this one by Discovery , represented the return to flight for the Space Shuttle. During this mission the crew launched the TDRS 3 satellite.
4 May 1989-1993 The highly successful Magellan mission to Venus began on this date following launch on STS-30. The Magellan spacecraft set out for Venus to map the surface from orbit with imaging radar. The probe arrived at Venus in Sep. 1990 and mapped 99 percent of the surface at high resolution, parts of it in stereo. The amount of digital imaging data the spacecraft returned was more than twice the sum of all returns from previous missions. This data provided some surprises: among them the discovery that plate tectonics was at work on Venus and that lava flows showed clearly the evidence of volcanic activity. In 1993, at the end of its mission, NASA's Jet Propulsion Laboratory shut down the major functions of the Magellan spacecraft and scientists turned their attention to a detailed analysis of its data.
18 Oct. 1989-Present The Galileo spacecraft was launched from STS-34 on this date and began a gravityassisted journey to Jupiter, where it would send a probe into the atmosphere and observe the planet and its satellites for two years beginning in 1995. On the way to Jupiter Galileo encountered both Venus and the Earth and made the first close flyby of asteroid Gaspra in 1991, providing scientific data on all. But soon after deployment from the Space Shuttle, NASA engineers learned that Galileo's umbrellalike, highgain antenna could not be fully deployed. Without this antenna, communication with the spacecraft was both more difficult and time-consuming, and data transmission was greatly hampered. The engineering team working on the project tried a series of cooling exercises designed to shrink the antenna central tower and enable its deployment. Over a period of several months they worked on this maneuver repeatedly, but were unable to free the antenna.
24 Apr. 1990-Present Launch of the Hubble Space Telescope from the Space Shuttle after more than a decade of puritanically-funded but productive research and development on the project in the 1970s and early 1980s. Soon after launch, controllers found that the telescope was flawed by a "spherical aberration," a mirror defect only 1/25th the width of a human hair, that prevented Hubble from focusing all light to a single point. At first many believed that the spherical aberration would cripple the 43foot-long telescope, and NASA received considerable negative publicity, but soon scientists found a way with computer enhancement to work around the abnormality and engineers planned a Shuttle repair mission to fully correct it with an additional instrument. Even with the aberration, Hubble has made many important astronomical discoveries, including striking images of galaxy M87, providing evidence of a potentially massive black hole.
17 Dec. 1990 Because of the difficulties NASA encountered in its major programs at the end of the 1980s, as well as the need periodically to review status and chart the course for the future, in 1990 President George Bush chartered an Advisory Committee on the Future of the U.S. Space Program under the leadership of Norman Augustine, chief executive officer of Martin Marietta. On this date Augustine submitted his commission's report, delineating the chief objectives of the agency and recommending several key actions. All of these related to the need to create a balanced space program-one that included human space flight, robotic probes, space science, applications, and exploration-within a tightly constrained budget.
15 Jul. 1991 In a joint program involving NASA's Ames, Dryden, Langley, and Lewis research centers, research pilot Edward Schneider flew the F/A-18 High Angle-of-Attack Research Vehicle (HARV) for the first time with thrust-vectoring paddles engaged to enhance control and maneuvering at high angles of attack (angles at which the wind in the aircraft's flight path hit the wing). This research was important because the tendency of airplanes to stall at low speeds and high angles of attack severely limited their ability to maneuver. The HARV vehicle had begun control flights without the paddles to study airflow at up to 55 degrees angle of attack in 1987. Then in the five years after 1991, the HARV reached a controllable angle of attack of 70 degrees and also explored the maneuverability and control benefits of thrust vectoring. Together with related programs in the X-31 and F-15 ACTIVE (Advanced Controls for Integrated Vehicles), the HARV demonstrated a significant enhancement of high angle-of-attack agility and maneuverability. In addition, the HARV made a significant contribution to the applicability of computational fluid dynamics (CFD) to high angle-of-attack flows by providing a comparison of CFD, wind-tunnel, and flight data at the same scale.
2-16 May 1992 STS-49: First flight of Space Shuttle Endeavour, including the first three-person spacewalk, which captured a private satellite for repair and reboost.
25 Sep. 1992-29 Oct. 1993 The Mars Observer was launched for an epic-making flight to the Red Planet. The spacecraft was to provide the most detailed data available about Mars as it orbited the planet since what had been collected by the Viking probes of the mid-1970s. The mission was progressing smoothly until about 9 p.m. on Saturday, 21 Aug. 1993, three days before the spacecraft's entry into orbit around Mars, when controllers lost contact with it. The engineering team working on the project at the Jet Propulsion Laboratory responded with a series of commands to turn on the spacecraft's transmitter and to point the spacecraft's antennas toward Earth. No signal from the spacecraft, however the Mars Observer was not heard from again, probably because of an explosion in the propulsion system's tanks as they were pressurized. With no response from the Mars Observer , on 29 Oct. 1993, flight controllers concluded scheduled operations.
2 Dec. 1993 Astronauts Richard O. Covey and Kenneth D. Bowersox piloted Space Shuttle Endeavour (STS-61) on a highly successful mission to repair the optics of the Hubble Space Telescope (HST) and perform routine servicing on the orbiting observatory. Following a precise and flawless rendezvous, grapple, and berthing of the telescope in the cargo bay of the Shuttle, the Endeavour flight crew, in concert with controllers at Johnson Space Center, Houston, Texas, and Goddard Space Flight Center, Greenbelt, Maryland, completed all eleven planned servicing tasks during five extravehicular activities for full accomplishment of all STS-61 servicing objectives. This included installation of a new Wide Field & Planetary Camera and sets of corrective optics for all the other instruments, as well as replacement of faulty solar arrays, gyroscopes, magnetometers, and electrical components to restore the reliability of the observatory subsystem. The Endeavour then provided HST with a reboost into a 321-nautical-mile, nearly circular orbit. Re-deployment of a healthy HST back into orbit using the shuttle robotic arm occurred at 5:26 a.m. EST on 10 Dec., and the telescope was once again a fully operational, free-flying spacecraft with vastly improved optics. Orbital verification of HST's improved capabilities occurred in early Jan., well ahead of the March schedule. Endeavour , the newest of the orbiters, was named after the 18th century vessel captained by British explorer Capt. James Cook. The new Shuttle craft took its maiden voyage in May 1992.
25 Jan.-3 May 1994 After launch from Cape Canaveral, Florida, the joint Department of Defense/NASA Clementine mission mapped most of the lunar surface at a number of resolutions and wavelengths from Ultra Violet to Infrared. The spacecraft was launched on 25 Jan., at 16:34 local time, and the nominal lunar mission lasted until the spacecraft left lunar orbit on 3 May. A malfunction in one of the on-board computers on 7 May at 14:39 UTC (9:39 AM EST) caused a thruster to fire until it had used up all of its fuel, leaving the spacecraft spinning at about 80 RPM with no spin control. The spacecraft remained in geocentric orbit and continued testing the spacecraft components until the end of mission. Perhaps the most important scientific finding of the mission was the possibility of an abundant supply of water on the Moon that would make establishment of a self-sustaining lunar colony much more feasible and less expensive than presently thought. Study of lunar samples revealed that the interior of the Moon is essentially devoid of water, so no underground supplies could be used by lunar inhabitants. However, the lunar surface is bombarded with water-rich objects such as comets, and scientists have suspected that some of the water in these objects could migrate to permanently dark areas at the lunar poles, perhaps accumulating to useable quantities. Analysis of data returned from a radio-wave experiment performed by Clementine revealed that deposits of ice exist in permanently dark regions near the south pole of the Moon. Initial estimates suggested that the volume of a small lake exists, 1 billion cubic meters.
3-11 Feb. 1994 Astronauts Charles F. Bolden and Kenneth S. Reightler, Jr., flew Space Shuttle Discovery (STS-60) on a historic mission featuring the first Russian cosmonaut to fly on a U.S. mission in space, Mission Specialist Sergei K. Krikalev, veteran of two lengthy stays aboard the Russian Mir Space Station. This mission underlined the newly inaugurated cooperation in space between Russia and the U.S., featuring Russia's becoming an international partner in the international space station effort involving the U.S. and its international partners.
3-11 Feb. 1995 Exactly one year after a major cooperative flight with the Russians in STS-60, NASA's Space Shuttle Discovery , this time STS-63, flew another historic mission featuring the flyby of the Russian Mir Space Station. It also featured the first time that a woman pilot, Eileen M. Collins, flew the Space Shuttle. Vladimir Titov is also aboard, the first Russian to be launched aboard a U.S. spacecraft.
27 Jun.-7 Jul. 1995 Twenty years after the world's two greatest spacefaring nations and Cold War rivals staged a dramatic linkup between piloted spacecraft in the Apollo-Soyuz Test Project during the summer of 1975, the space programs of the United States and Russia again met in Earth orbit when the Space Shuttle Atlantis docked to the Mir Space Station. The STS䏛 mission by Atlantis was the first of seven planned shuttle/ Mir linkups between 1995 and 1997, including rendezvous, docking, and crew transfers. Atlantis docked with Mir on 29 Jul., and the combine crew of astronauts and cosmonauts performed several experiments. At the end of joint docked activities on 4 Jul., two Russian cosmonauts lifted to the Mir by the shuttle, assumed responsibility for operations of the Mir station. At the same time, the Mir䎦 crew, who had been aboard the station since 16 Mar. 1995-Commander Vladimir Dezhurov, Flight Engineer Gennady Strekalov, and American astronaut Norm Thagard-joined the STS䏛 crew for the return trip to Earth. Thagard returned home with the American record for a single space flight with more than 100 days in space. The previous record had been held by the Skylabۆ crew with 84 days in 1973. Thagard broke that record on 6 Jun. 1995.
11-20 Nov. 1995 This mission by the Space Shuttle Atlantis carried up and attached a Russian-built docking port and orbiter docking system to the Mir space station for use in future shuttle dockings.
28 Nov. 1995 A McDonnell-Douglas MD-11-equipped with a propulsion controlled aircraft (PCA) system developed by NASA's Dryden Flight Research Center, McDonnell Douglas Aerospace, Pratt & Whitney Aircraft, and Honeywell, Inc.-made the first-ever safe, fully automated landing of a transport aircraft using only engine thrust for control. NASA Dryden engineers and pilots began developing the system in the wake of a long series of failures of hydraulic flight control systems in the 1970s, three of which resulted in crashes claiming the lives of over 1,200 people. The system evolved through landings by NASA research pilot Gordon Fullerton of a NASA F-15 research aircraft using a similar system in April 1993 and of the MD-11 in August 1995 with a prototype system that required him to use cockpit knobs and thumbwheels aided by a still-developing software system. The system used for landings on 28 and 30 November 1995 relieved the pilot of virtually all manual manipulation beyond engaging the auto-land system. The PCA system has the potential of providing aircraft a back-up system to enable safe landings in the event the airplane loses its hydraulic controls.
7 Dec. 1995 Galileo : Probe released into Jupiter's atmosphere.
22-31 Mar. 1996 In this Atlantis shuttle mission to dock with the Russian space station Mir , the United States left astronaut Shannon Lucid, the first U.S. woman to fly on the station, aboard for a total of five months.
7 Aug. 1996 NASA announced that a team of its scientists had uncovered evidence, however not conclusive proof, that microscopic life may have once existed on Mars. The team of scientists recounted the meteor's history, found in Antarctica in 1984 and why they suspect it is from Mars. The 4.2 pound, potato-sized rock, identified as ALH84001, is approximately the same age as the Red Planet. When ALH84001 formed as an igneous rock about 4.5 billion years ago, Mars was much warmer and probably contained oceans hospitable to life. Then, about 15 million years ago, a large asteroid hit the Red Planet and jettisoned the rock into space where it remained until it crashed into Antarctica about 11,000 B.C. The nine-member team of NASA and Stanford University scientists, led by Johnson Space Center scientists David S. McKay and Everett K. Gibson, Jr., presented three compelling, but not conclusive, pieces of evidence that suggest that fossil-like remains of Martian microorganisms, which date back 3.6 billion years, are present in ALH84001. During their two-and-a-half year investigation, the JSC team found trace minerals in the meteor that are usually associated with microscopic organisms. They also used a newly developed electron microscope to uncover possible microfossils that measure between 1/100 to 1/1000 the diameter of a human hair. Finally, discovered organic molecules called polycyclic aromatic hydrocarbons (PAHs) in ALH84001, usually resulting when microorganisms die and their complex organic molecules breakdown. They called for additional research from other scientists either to confirm or refute these findings.
13 Aug. 1996 Data from NASA's Galileo probe at Jupiter revealed that the gas giant's moon, Europa, may harbor "warm ice" or even liquid water-key elements in life-sustaining environments. Many scientists and science fiction writers have speculated that Europa-in addition to Mars and Saturn's moon Titan-is one of the three planetary bodies in this Solar System that might possess, or may have possessed, an environment where primitive life can exist. Galileo's photos of Europa were taken during a flyby of Ganymede some 96,000 miles away from Europa. They reveal what look like ice floes similar to those seen in Earth's polar regions. The pictures also reveal what look like giant cracks in Europa's ice where warm water "environmental niches" may exist. Although NASA officials stressed that the photos do not conclusively prove anything, they do think that the images are exciting, compelling, and suggestive.
16-26 Sep. 1996 The Atlantis docked with Mir and retrieved Shannon Lucid and left John Blaha for continued joint operations aboard the Russian station. Astronaut Lucid set a new record for an American living in space and broke the world's record for a woman living in space by spending 181 days aboard the Russian Mir Space Station. President Clinton presented Lucid, who conducted microgravity and life sciences experiments aboard the Mir , with the Congressional Space Medal of Honor in an early December ceremony, citing Lucid "for her contributions to international cooperation in space. Shannon Lucid is an explorer in the best tradition of those who dare to challenge the unknown."
13 Jan. 1997 NASA scientists announced the discovery of three black holes in three normal galaxies, suggesting that nearly all galaxies may harbor supermassive black holes which once powered quasars (extremely luminous nuclei of galaxies), but now are quiescent. This conclusion was based on a census of 27 nearby galaxies carried out by NASA's Hubble Space Telescope and ground-based telescopes in Hawaii, which were used to conduct a spectroscopic and photometric survey of galaxies to find black holes which have consumed the mass of millions of Sun-like stars. The key results are: (1) supermassive black holes are so common that nearly every large galaxy has one, (2) a black hole's mass is proportional to the mass of the host galaxy, so that, for example, a galaxy twice as massive as another would have a black hole that is also twice as massive, (3) the number and masses of the black holes found are consistent with what would have been required to power the quasars.
11-21 Feb. 1997 In a record five extravehicular activity (EVA) operations, astronauts from the shuttle Discovery performed the second Hubble Space Telescope servicing mission. This mission replaced the near-infra red camera (NICMOS) and the two-dimensional spectrograph and repaired insulation on the telescope.
20 Feb. 1997 The space probe Galileo exploring Jupiter and its moons discovered Icebergs on Europa. Images captured during Galileo's closest flyby of Europa showed features of the Jovian moon, lending credence to the possibility of hidden, subsurface oceans. The findings generated new questions about the possibility of life on Europa.
1-7 May 1997 A fleet of spacecraft with the International Solar Terrestrial Physics (ISTP) program watched for a break in Comet Hale-Bopp's plasma ion tail. Amateur astronomers around the world were also put on watch the first week of May 1997 when space scientists predicted based on earlier data from ISTP spacecraft estimated that Comet Hale-Bopp's ion tail likely would be disrupted when it enters a region around the Sun known as the "current sheet." Scientists explained that the disruption was a complicated interaction between the comet and the Sun's influence and magnetic fields. The comet first appeared in the spring and excited astronomers for its high visibility and ready analysis.
4 Jul. 1997 The inexpensive Mars Pathfinder (costing only $267 million) landed on Mars, after its launch in December 1996. A small, 23-pound robotic rover, named Sojourner , departed the main lander and began to record weather patterns, atmospheric opacity, and the chemical composition of rocks washed down into the Ares Vallis flood plain, an ancient outflow channel in Mars' northern hemisphere. This vehicle completed its projected milestone 30-day mission on 3 Aug. 1997, capturing far more data on the atmosphere, weather, and geology of Mars than scientists had expected. In all, the Pathfinder mission returned more than 1.2 gigabits (1.2 billion bits) of data and over 10,000 tantalizing pictures of the Martian landscape. The images from both craft were posted to the Internet, to which individuals turned for information about the mission more than 500 million times through the end of July.
25 Aug. 1997-Present Real-time data from NASA's Advanced Composition Explorer were incorporated into the daily weather forecasting system by the end of the year. NOAA's Space Environment Center in Boulder, Colorado, used data from this system to track solar disturbances. Positioned between the Sun and the Earth, the spacecraft intercepts solar winds and geomagnetic activity and allows forecasters to warn users such as satellite operators, power control centers, and others of the threat to their electronic systems resulting from sudden fluctuations in solar energy reaching Earth.
11 Sep. 1997 The Mars Global Surveyor space probe, launched in December 1996, entered orbit at the red planet. The spacecraft's magnetometer, detected a magnetic field on 15 Sep. The existence of a planetary magnetic field has important implications for the geological history of Mars and for the possible development and continued existence of life on Mars. The magnetic field had important implications for the evolution of Mars. Planets like Earth, Jupiter, and Saturn generate their magnetic fields by means of a dynamo made up of moving molten metal at the core. This metal is a very good conductor of electricity, and the rotation of the planet creates electrical currents deep within the planet that give rise to the magnetic field. A molten interior suggests the existence of internal heat sources, which could give rise to volcanoes and a flowing crust responsible for moving continents over geologic time periods.
25 Sep.-6 Oct. 1997 In this seventh docking mission with the Russian space station Mir, the shuttle Atlantis delivered three Russian air tanks and nine Mir batteries (170 pounds each). It also delivered a Spektor module repair kit (500 pounds), which enabled the station crew to begin serious repairs damaged in the Progress collision of 25 Jun. The mission also delivered 1,400 pounds of water 1,033 pounds of U.S. science items and 3,000 pounds of Russian supplies. During this mission Russian cosmonauts Parazynski and Titov conduct an EVA to retrieve four environmental effects space exposure experiments (MEEPS) on Mir's module. Atlantis also flew around Mir to assess the damage to the station. The astronaut Michael Foale also departed for Earth after a stay of nearly five months and was replaced by astronaut David Wolf.
15 Oct. 1997 The international Cassini space probe mission left Earth bound for Saturn atop an Air Force Titan IV-B/Centaur rocket in a picture-perfect launch at Cape Canaveral, Florida. With the European Space Agency's Huygens probe and a high-gain antenna provided by the Italian Space Agency, Cassini will arrive at Saturn on 1 July 2004.
Dec. 1997 Scientists using the joint European Space Agency/NASA Solar and Heliospheric Observatory (SOHO) spacecraft have discovered "jet streams" or "rivers" of hot, electrically charged plasma flowing beneath the surface of the Sun. These new findings will help scientists understand the famous 11-year sunspot cycle and associated increases in solar activity that can disrupt the Earth's power and communications systems.
6 Jan. 1998 Lunar Prospector was launched on this date for a one-year polar mission to explore the Moon, especially whether or not water ice is buried inside the lunar crust. Developed as part of the Discovery program of frequent, low-cost missions, Lunar Prospector carried a small payload of only five instruments. Besides water, Lunar Prospector was also to look for other natural resources, such as minerals and gases, that could be used to build and sustain a future human lunar base or in manufacturing fuel for launching spacecraft from the Moon to the rest of the Solar System. The spacecraft's Gamma Ray Spectrometer will also collect a large amount of scientific data about chemical composition of the lunar surface and will measure the Moon's magnetic and gravitational fields. Its Alpha Particle Spectrometer will sniff out small quantities of gases that leak out from the lunar interior. Collectively, the scientific data that Prospector will send back to Earth will help researchers construct a more complete and detailed map of the Moon. In Mar. 1998 Lunar Prospector detected the presence of water ice at both lunar poles, using data from the spacecraft's neutron spectrometer instrument. The lunar water ice is estimated at an overall range of eleven million to 330 million tons of lunar water ice dispersed over 3,600 to 18,000 square miles of water ice-bearing deposits across the northern pole, and an additional 1,800 to 7,200 square miles across the southern polar region. Furthermore, twice as much of the water ice mixture was detected by Lunar Prospector at the Moon's north pole as at the south.
29 Jan. 1998 An International Space Station agreement among 15 countries met in Washington to sign agreements to establish the framework for cooperation among the partners on the design, development, operation, and utilization of the Space Station. Acting Secretary of State Strobe Talbott signed the 1998 Intergovernmental Agreement on Space Station Cooperation, along with representatives of Russia, Japan, Canada and participating countries of the European Space Agency (Belgium, Denmark, France, Germany, Italy, the Netherlands, Norway, Spain, Sweden, Switzerland and the United Kingdom). Three bilateral memoranda of understanding were also signed by NASA Administrator Daniel S. Goldin separately with his counterparts: Russian Space Agency General Director Yuri Koptev, ESA Director General Antonio Rodota and Canadian Space Agency President William (Mac) Evans.
12 Mar. 1998 Development of the X-38, a spacecraft design planned for use as a future International Space Station emergency crew return "lifeboat," passed a major milestone today with a successful first unpiloted flight test. The first X-38 atmospheric test vehicle was dropped from under the wing of NASA's B-52 aircraft at the Dryden Flight Research Center, Edwards, CA, at 11:30 a.m. EST and completed a descent from a 23,000 foot altitude at 11:38 a.m. EST. The test focused on the use of the X-38's parafoil parachute, which deployed as planned within seconds after the vehicle's release from the B-52 and guided the test craft to landing. Atmospheric tests of the X-38 will continue for the next two years using three increasingly complex test vehicles. The drop tests will increase in altitude to a height of 50,000 feet and include longer flight times for the test craft prior to deployment of the parafoil. In 2000, an unpiloted space test vehicle is planned to be deployed from a Space Shuttle and descend to a landing. The X-38 crew return vehicle is targeted to begin operations aboard the International Space Station in 2003. Eventually, the X-38 will become the first new human spacecraft designed to return humans from orbit in more than twenty years, and it is being developed at a fraction of the cost of past human space vehicles. The primary application of the new spacecraft would be as an International Space Station "lifeboat," but the project also aims at developing a design that could be easily modified for other uses, such as a possible joint U.S. and international human spacecraft that could be launched on expendable rockets as well as the Space Shuttle.
May 28, 1998 The Hubble Space Telescope gave humanity its first direct image of what is probably a planet outside our solar system-one apparently that has been ejected into deep space by its parent stars. Located in a star-forming region in the constellation Taurus, the object called TMR-1C, appears to lie at the end of a strange filament of light that suggests it has apparently been flung away from the vicinity of a newly forming pair of binary stars. At a distance of 450 light-years, the same distance as the newly formed stars, the candidate protoplanet would be ten thousand times less luminous than the Sun. If the object is a few hundred thousand years old, the same age as the newly formed star system which appears to have ejected it, it was estimated to be two to three times the mass of Jupiter, the largest gas giant planet in our Solar System.
The niobium-92–zirconium-92 ( 92 Nb– 92 Zr) decay system with a half-life of 37 Ma has great potential to date the evolution of planetary materials in the early Solar System. Moreover, the initial abundance of the p-process isotope 92 Nb in the Solar System is important for quantifying the contribution of p-process nucleosynthesis in astrophysical models. Current estimates of the initial 92 Nb/ 93 Nb ratios have large uncertainties compromising the use of the 92 Nb– 92 Zr cosmochronometer and leaving nucleosynthetic models poorly constrained. Here, the initial 92 Nb abundance is determined to high precision by combining the 92 Nb– 92 Zr systematics of cogenetic rutiles and zircons from mesosiderites with U–Pb dating of the same zircons. The mineral pair indicates that the 92 Nb/ 93 Nb ratio of the Solar System started with (1.66 ± 0.10) × 10 −5 , and their 92 Zr/ 90 Zr ratios can be explained by a three-stage Nb–Zr evolution on the mesosiderite parent body. Because of the improvement by a factor of 6 of the precision of the initial Solar System 92 Nb/ 93 Nb, we can show that the presence of 92 Nb in the early Solar System provides further evidence that both type Ia supernovae and core-collapse supernovae contributed to the light p-process nuclei.