The 21st Century

ICESat / CHIPSat ~ launched January 2003 ~ The ICESat satellite is studying the global sea level and the condition of the polar ice sheets, while the CHIPSat satellite is characterizing the properties of the hot gas in the interstellar medium, in order to better understand how stars form.

SORCE ~ launched January 2003 ~ This satellite is measuring incoming radiation from the Sun in order to determine its effect on Earth's atmosphere and climate. It is studying x-ray, ultraviolet, visible, and infrared radiation.

GALEX ~ launched April 2003 ~ The GALEX satellite will observe a million galaxies up to 10 billion years old in order to determine when and how the first galaxies originated.

Mars Exploration Rover Opportunity ~ launched July 2003 ~ This robotic explorer will land on Mars and study the rocks and soil in order to get a better idea of the past existence of water on Mars.

Space Infrared Telescope Facility ~ launch date August 2003 ~ The SIRTF is a successor to the Hubble Space Telescope. It is an infrared telescope that will study the most distant and coldest objects in the universe.

The 1990s

Hubble Space Telescope ~ launched April 1990 ~ The HST has proven to be the most successful telescope ever built. Although some ground-based telescopes are larger, they have the disadvantage of peering through the atmosphere of the Earth. Hubble, on the other hand, is in orbit 380 miles above Earth, so it does not encounter any atmospheric disturbances. It has taken photographs of close objects such as the Moon and planets as well as images of the most distant astronomical objects ever viewed by humans. When Hubble was first launched, there was a small aberration in the telescope's mirror. In 1993, a team of astronauts rendezvoused with Hubble and were able to fix the problem. The photos Hubble has taken since this servicing mission are unparalleled in quality, and have literally changed the face of astronomy. HST has now viewed almost 20,000 objects and taken more than 350,000 pictures!

Ulysses ~ launched October 1990 ~ This is a joint U.S. and European solar observatory that passes the poles of the Sun every five years. It gives a view of the Sun not available from Earth.

SOHO ~ launched December 1995 ~ The Solar and Heliospheric Observatory is a joint U.S. and European mission. It is studying the internal structure of the Sun, its outer atmosphere, and the origin of the solar wind. It has been giving astronomers an uninterrupted view of the Sun, and hopefully will provide information on the affect of the Sun on Earth's environment.

Near-Earth Asteroid Rendezvous (NEAR) ~ launched February 1996 ~ This probe entered the asteroid belt between Mars and Jupiter and concentrated on the asteroids Mathilde and Eros.

Mars Global Surveyor ~ launched November 1996 ~ This probe has been orbiting Mars since 1997, sending back hundreds of photographs to make the most detailed map of the surface. Scientifically, the surveyor has hinted that Mars may be a more hospitable environment to life than was previously imagined: it is wet, volcanic, and geologically younger than was previously believed.

Mars Pathfinder ~ launched December 1996 ~ This unique mission was a landmark for NASA, because it was designed innovatively to cut costs in a program whose budgets are constantly being squeezed. Once in orbit around Mars, the lander separated from the orbiter, and a parachute opened in order to slow the descent. A system of heavy-duty airbags inflated around the lander, and it bounced along the surface in a rocky valley. The airbags deflated, and the lander opened like a flower. A special rover named Sojourner was then able to leave the lander and explore the local surface. Sojourner was able to take photographs and geologically test the rocks and dust, which greatly improved scientists' understanding of the red planet. In addition, the whole scene was broadcast live on television and the internet, making it a very popular mission with the general public.

Cassini ~ launched October 1997 ~ In 2004, Cassini will rendezvous with Saturn in a mission which is similar to the Galileo mission of Jupiter. It will land on Saturn's biggest moon, Titan, to study the possibility of life evolving on this moon. Scientists believe that the relatively harsh environment on Titan is similar to the environment on Earth when life first formed.

International Space Station ~ building started in 1998 ~ The first extensive cooperation between space agencies from different countries started in 1993, when the US, Russia, and other European countries decided to pool their resources to build an international station in space. Human crews are living aboard the space station for extended periods of time, which has allowed scientists to study the reaction of the body to living in a zero-gravity environment. Hundreds of microgravity scientific experiments which are not possible on Earth have been conducted by the astronauts. Experiments have been done in the fields of physics, geology, medicine, and technology.

Chandra X-ray Observatory ~ launched July 1999 ~ This observatory is in orbit around the Earth. Its goal is to study high-energy regions of space containing exotic objects such as black holes and the remnants of supernovae. It has already discovered a new type of black hole, and has recorded x-rays coming from comets. It can observe X-rays from particles during the last second before they fall into a black hole. Chandra flies 200 times higher above the Earth than does the Hubble Space Telescope.

The 1980s

Space Shuttles ~ first flight April 1981 ~ The space shuttles were designed as a new type of spacecraft that could withstand re-entry into the Earth's atmosphere and subsequently be used again for later missions. There have been five space shuttles: Columbia, Discovery, Endeavor, Atlantis, and Challenger. The first American woman in space, Sally Ride, lifted off in June 1983. The Challenger exploded during launch on January 28, 1986, killing all seven crew members. The shuttle program was then grounded for more than two years while safety issues were reviewed. On ... the Columbia exploded during reentry, also killing all seven astronauts. It has been determined that a piece of foam hit the wing during launch, causing an unstable condition for re-entering the atmosphere. Aside from these tragedies, the space shuttle program has been very successful, having completed more than 65 missions and acting as both a transport device and a scientific laboratory.

Venera 15&16 ~ launched 1983 ~ These two Soviet crafts mapped Venus' surface.

Mir Space Station ~ launched February 1986 ~ This was the first space station, designed to hold a human crew in orbit of the Earth for extended periods of time. Mir was in service for more than 10 years, during which time many NASA astronauts had the chance to practice living in space.

Magellan ~ launched May 1989 ~ Venus' landscape and its magnetic field were studied by this craft, along with the distribution of mass within the planet. It provided the first comprehensive look at the geology of Venus.

Galileo ~ launched October 1989 ~ In 1995, Galileo arrived at Jupiter and shot a probe into the atmosphere. It spent several years doing a survey of the planet and several of its moons. Europa was found to be particularly interesting, with an ocean under a crust of ice. The volcanic moon Io was also studied.

The 1970s

Apollo 13 ~ launched April 1970 ~ This Apollo mission did not make it to the Moon, because an oxygen tank burst. It is considered one of NASA's finest achievements, however, since so many obstacles were overcome in bringing the astronauts safely back to Earth.

Venera 1-10 ~ launched 1970-1982 ~ These Soviet spacecraft landed on the surface of Venus. Because of the intense conditions at the surface, they only worked for a few minutes, but four of the missions sent back photographs of the surface, which was covered with lava rocks.

Apollo 14 ~ launched February 5, 1971 ~ Alan Shepard and Edgar Mitchell walked on the Moon.

Mariner 9 ~ launched May 1971 ~ This was the first spacecraft to actually orbit the planet Mars. The surface was again photographed and the atmosphere was analyzed extensively. Apollo 15 ~ Launched July 30, 1971 ~ David Scott and James Irwin walked on the Moon.

Pioneer 10 ~ launched March 1972 ~ The first flyby of Jupiter was done in 1973. The atmosphere and magnetic field were studied. Pioneer 10 continued to communicate with Earth on its way out of the solar system, and in January 2003, its last signal was recorded. As of July 2003, Pioneer 10 is 7.83 billion miles from the Earth, and it is traveling at a speed of 27,317 miles per hour.

Apollo 16 ~ launched April 20, 1972 ~ John Young and Charles Duke walked on the Moon.

Apollo 17 ~ launched December 11, 1972 ~ Eugene Cernan and Harrison Schmitt walked on the Moon. Schmitt was the first scientist chosen to be an astronaut (he was a geologist).

Pioneer 11 ~ launched April 1973 ~ This probe followed Pioneer 10 in a trip to Jupiter, and then went on to Saturn. Its mission ended in November 1995, when the last communication was received. If Pioneer 11 survives long enough, in 4 million years it will pass near one of the stars in the constellation Aquila.

Mariner 10 ~ launched November 1973 ~ This is the only American spacecraft sent to Mercury. It flew by the planet three times to take pictures, which showed that Mercury has an iron core and a moon-like surface that is constantly pelted by solar system objects. The probe reached Mercury with the help of the gravitational influence of Venus. It was the first mission to use this gravity assist trajectory, and had the benefit of studying both planets.

Apollo-Soyuz Test Project ~ launched July 1975 ~ This was the first collaboration between the space programs of the United States and the Soviet Union. Rendezvous and docking procedures were tested when spacecraft were launched separately from each country and then met in space.

Viking 1 & 2 ~ launched August and September 1975 ~ The purpose of these two missions was to search for signs of life on Mars. They found no signs of life in either the past or the present, but took many photographs in order to map the surface of Mars.

Voyager 2 ~ launched August 1977 ~ Voyager 2 also did in-depth studies of Jupiter and its moons, and found a thin ring around the planet. Its study of Saturn helped map the atmosphere's quick-moving clouds. It then went on to the outer planets of the solar system. It arrived at Uranus in 1986, and sent back photos of a planet which appeared blue because of its methane atmosphere. The interesting moons of Uranus were also photographed. In 1989, it reached Neptune, and found that this planet has an active atmosphere. Also of interest was the fact that Neptune's moon Triton has a thin atmosphere. After this grand tour, Voyager 2 headed out of the solar system.

Voyager 1 ~ launched September 1977 ~ Voyager 1 was a sophisticated probe which did a flyby of Jupiter and many of its moons. It found that the moon Io is the most volcanically active body in the solar system. Then it headed to Saturn to study its ring system and moons. It then started on a path out of the solar system. It is now almost 8 billion miles from the Earth, making it the most distant human-made object, and is at the edge of the solar system.

Pioneer Venus ~ launched May 1978 ~ This American craft mapped Venus' volcanic surface until 1992.

The 1960s

Pioneer 5 ~ launched March 1960 ~ The first study of the magnetic field between the planets was conducted by Pioneer 5.

Vostok I ~ launched April 12, 1961 ~ The first person in space was Yuri Gagarin, a Soviet Air Force lieutenant. He orbited the Earth once in a flight that lasted 108 minutes. The Vostok spacecraft was flown with a combination of ground control and onboard autopilot commands.

Mercury ~ launched May 1961 ~ Alan Shepherd was America's first man in space. The one-man spacecraft went outside Earth's atmosphere but did not go into orbit.

Vostok 2 ~ launched August 1961 ~ The Soviets made another manned flight which lasted a day and orbited the Earth 17 times.

Mercury ~ launched February 1962 ~ The first American to orbit the Earth was John Glenn, who orbited the planet three times in a Mercury one-man spacecraft.

Mariner 2 ~ launched August 1962 ~ This was the first spacecraft to perform a flyby of another planet, in this case Venus. It found that the surface of Venus was just as hot as that of Mercury, and that the atmosphere is 100 times heavier than Earth's atmosphere.

Vostok 6 ~ launched June 1963 ~ Valentina Tereshkova became the first woman in space. She orbited the Earth 48 times in Vostok 6.

Mariner 4 ~ launched November 1964 ~ This was the first successful flyby of Mars, which took place in 1965. It took photographs which showed a moonlike surface.

Voskhod 2 ~ launched March 1965 ~ Alexei Leonov was the first person to perform a spacewalk.

Gemini 4 ~ launched June 1965 ~ Edward White became the first American to walk in space. The goal of the Gemini program was to practice space operations such as docking and reentry The Gemini spacecraft held two astronauts, and provided important information on how weightlessness affects the human body.

Pioneer 6-9 ~ launched between December 1965-November 1968 ~ These crafts measured properties of the solar wind and the sun's magnetic field.

Mariner 5 ~ launched June 1967 ~ This Mariner mission was designed to study Venus' atmosphere using radio waves.

Apollo 7 ~ launched October 1968 ~ The Apollo spacecraft orbited the Earth in order to test the command module.

Apollo 8 ~ launched December 1968 ~ The first manned mission to the Moon successfully orbited for a day and then returned to Earth.

Mariner 6 & 7 ~ launched February and March 1969 ~ These two spacecraft were designed to work together to provide a more detailed view of Mars' surface. It showed an abundance of channels on the surface, which might have been carved by water, and a number of volcanoes, valleys, and canyons.

Apollo 9 ~ launched March 1969 ~ In order to test the lunar landers that would take astronauts to the surface of the Moon, the Apollo 9 spacecraft performed a dry run in an Earth orbit.

Apollo 10 ~ launched May 1969 ~ This mission was an unmanned dress rehearsal for bringing the first astronauts to the Moon. The lunar lander was flown close to the Moon's surface (50,000 feet away), but did not actually land.

Apollo 11 ~ launched July 20, 1969 ~ The first men, Neil Armstrong and Buzz Aldrin, reached the moon. As Armstrong stepped out onto the Sea of Tranquility, he said, "That's one small step for a man, one giant leap for mankind." They spent only two hours on the surface collecting moon rocks, and then returned in the lunar lander to the orbiting Apollo spacecraft.

Apollo 12 ~ launched November 19, 1969 ~ Charles Conrad and Alan Bean walked on the Moon.

The 1950s

Sputnik 1 ~ launched October 1957 ~ The Soviet Union launched the first satellite, which started the 'space race' between the United States and the Soviet Union.

Sputnik 2 ~ launched November 1957 ~ The Soviet Union's second satellite carried the first living thing, a dog named Laika, into space.

Explorer 1 ~ launched January 1958 ~ The first American satellite recorded the existence of the Earth's Van Allen Radiation Belt, a band of radiation encircling the Earth. The Van Allen belt affects the amount of radiation from the Sun that hits the Earth.

Pioneer 1 ~ launched October 1958 ~ The first Pioneer spacecraft studied the Earth's Van Allen Radiation belt, which had been discovered by the Explorer I.

Pioneer 3 ~ launched December 1958 ~ A second radiation belt around the Earth was discovered by this satellite.

Pioneer 4 ~ launched March 1959 ~ This was the first American spacecraft to escape the gravitational pull of the Earth and come close to the Moon. It gave scientists an idea of the radiation conditions of the Moon, in order to prepare for manned landings.

REFERENCES FOR THIS PAGE:

Robert Burnham, Alan Dyer, and Jeff Kanipe, Astronomy: The Definitive Guide, Barnes and Noble Books, 2003.

NASA History Fact Sheet, http://www.hq.nasa.gov/office/pao/History/factsheet.htm.

NSSDC Master Catalog Spacecraft Query Form, http://nssdc.gsfc.nasa.gov/nmc/sc-query.html