Chronology of Space Exploration

• Baloon flight - Europe - (1912)
  Discovered cosmic rays.
• NRL V-2 rocket - USA - (1946)
  First observed the Sun's UV spectrum.
• NRL V-2 rocket - USA - (1949)
  First observed solar x rays.
• Sputnik-1 - USSR - (1957)
  First artificial satellite.
• Explorer III - USA - (1958)
  Discovered Earth's radiation belt.
• Luna 1 - USSR - 361 kg - (Jan 2, 1959)
  Luna 1 discovered the solar wind. It is now in a solar orbit.
• Pioneer 4 - USA Distant Lunar Flyby - 5.9 kg - (Mar 3, 1959)
  Space probe is now in solar orbit.
• Luna 2 - USSR Lunar Hard Lander - 387 kg - (Sep 12, 1959)
  Luna 2 returned the first image of the Moon's hidden side. It impacted the surface of the moon on September 15, 1959.
• Luna 3 - USSR Lunar Far-side Flyby - 278.5 kg - (Oct 4, 1959)
  Encountered the Moon on October 7, 1959 and returned a photograph of the farside. Space probe is now in a decayed earth-moon orbit.
• Mars 1960A - USSR Probe - (Oct 10, 1960)
  Failed to reach Earth orbit.
• Mars 1960B - USSR Probe - (Oct 14, 1960)
  Failed to reach Earth orbit.
• Venera 1 - USSR Venus Flyby - 643.5 kg - (Feb 12, 1961)
  Now in solar orbit.
• Aerobee Rocket - USA - (1962)
  Observed the first x-ray star.
• Ranger 3 - USA Lunar Hard Lander - 327 kg - (Jan 26, 1962)
  Lunar probe missed the moon and is now in a solar orbit.
• Ranger 4 - USA Lunar Hard Lander - 328 kg - (Apr 23, 1962)
  Lunar probe impacted the surface of the Moon.
• Mariner 2 - USA Venus Flyby - 201 kg - (Aug 27, 1962)
  On December 14, 1962, Mariner 2 arrived at Venus at a distance of 34,800 km and scanned its surface with infrared and microwave radiometers capturing data that showed Venus's surface to be about 425°C (800°F). Three weeks after the Venus flyby Mariner 2 went off the air on Jan 3, 1963. It is now in a solar orbit.
• Ranger 5 - USA Lunar Flyby - 340 kg - (Oct 18, 1962)
  Lunar flyby is now in a solar orbit.
• Mars 1962A - USSR Probe - (Oct 24, 1962)
  Failed to leave Earth orbit.
• Mars 1 - USSR Mars Probe - 893 kg - (Nov 1, 1962)
  Communications failed en route.
• Mars 1962C - USSR Probe - (Nov 4, 1962)
  Failed to leave Earth orbit.
• Luna 4 - USSR Lunar Probe - 1,422 kg - (Apr 2, 1963)
  Lunar probe is now in an Earth Moon orbit.
• Ranger 6 - USA Lunar Hard Lander - 361.8 kg - (Jan 30, 1964)
  Lunar probe impacted the surface of the Moon.
• Zond 1 - USSR Venus Probe - 890 kg - (Apr 2, 1964)
  Now in solar orbit.
• Ranger 7 - USA Lunar Hard Lander - 362 kg - (Jul 28, 1964)
  Arrived on June 28, 1964 and sent pictures back at a close range. It impacted the Moon.
• Mariner 3 - USA Mars Flyby - 260 kg - (Nov 5, 1964)
  Mars flyby attempt. Solar panels did not open preventing flyby. Mariner 3 is now in a solar orbit.
• Mariner 4 - USA Mars Flyby - 260 kg - (Nov 28, 1964)
  Mariner 4 arrived at Mars on July 14, 1965 and passed within 9920 km of the planet's surface. It returned 22 close-up photos showing a cratered surface. The thin atmosphere was confirmed to be composed of carbon dioxide in the range of 5-10 mbar. A small intrinsic magnetic field was detected. Mariner 4 is now in a solar orbit.
• Pioneer 6 - USA Solar Probe - 63.4 kg - (Dec 16, 1965 - Present)
  Solar probe in solar orbit is still transmitting.
• Ranger 8 - USA Lunar Hard Lander - 366 kg - (Feb 17, 1965)
  Lunar probe sent pictures of its impact on the moon.
• Ranger 9 - USA Lunar HARD Lander - 366 kg - (Mar 21, 1965)
  Lunar probe sent pictures of its impact on the moon.
• Luna 5 - USSR Lunar Soft Lander - 1,474 kg - (May 9, 1965)
  The lunar soft-lander failed and impacted the moon.
• Luna 6 - USSR Lunar Soft Lander - 1,440 kg - (Jun 8, 1965)
  Missed the moon and is now in a solar orbit.
• Zond 3 - USSR Lunar Flyby - 959 kg - (Jul 18, 1965)
  Lunar flyby is now in a solar orbit.
• Luna 7 - USSR Lunar Soft Lander - 1,504 kg - (Oct 4, 1965)
  Luna 7 failed and impacted the moon.
• Venera 2 - USSR Venus Flyby - 962 kg - (Nov 12, 1965 - 1966)
  Communications failed just before arrival. Now in solar orbit.
• Venera 3 - USSR Venus Atmospheric Probe - 958 kg - (Nov 16, 1965 - 1966)
  Communications failed just before atmosphere entry. Crashed on Venus.
• Luna 8 - USSR Lunar Soft Lander - 1,550 kg - (Dec 3, 1965)
  Luna 8 failed and impacted the moon.
• Luna 9 - USSR Lunar Soft Lander - 1,580 kg - (Jan 31, 1966)
  Luna 9 landed on the lunar surface and retuned the photographs from the surface.
• Luna 10 - USSR Lunar Orbiter - 1,597 kg - (Mar 31, 1966)
  Luna 10 is currently in a lunar orbit.
• Surveyor 1 - USA Lunar Soft Lander - 269 kg - (Apr 30, 1966 to 1967)
  Surveyor 1 was the first American soft landing on the lunar surface.
• Lunar Orbiter 1 - USA Lunar Orbiter - 386 kg - (Aug 10, 1966)
  Lunar Orbiter 1 orbited the moon, photographed the far side and then impacted on command.
• Pioneer 7 - USA Solar Probe - 63 kg - (Aug 17, 1966 - ?)
  Solar probe in solar orbit was recently turned off.
• Luna 11 - USSR Lunar Orbiter - 1,638 kg - (Aug 24, 1966)
  Luna 11 is currently in lunar orbit.
• Surveyor 2 - USA Lunar Soft Lander - 292 kg - (Sep 20, 1966)
  Surveyor 2 failed and impacted the moon.
• Luna 12 - USSR Lunar Orbiter - 1,620 - (Oct 22, 1966-1967)
  Luna 12 is in lunar orbit.
• Lunar Orbiter 2 - USA Lunar Orbiter - 390 kg - (Nov 6, 1966)
  Orbited the moon, photographed the far side and potential Apollo landing sites then impacted on command.
• Luna 13 - USSR Lunar Soft Lander - 1,700 kg - (Dec 21, 1966)
  Landed on the lunar surface.
• Lunar Orbiter 3 - USA Lunar Orbiter - 385 kg - (Feb 5, 1967)
  Orbited the moon, photographed the far side and Apollo 12 landing site then impacted on command.
• Surveyor 3 - USA Lunar Soft Lander - 283 kg - (Apr 17, 1967)
  Landed on the lunar surface and pieces were brought back.
• Lunar Orbiter 4 - USA Lunar Orbiter - 390 kg - (May 4, 1967)
  Orbited the moon at a polar inclination and impacted on command.
• Venera 4 - USSR Venus Atmospheric Probe - 1,104 kg - (Jun 12, 1967)
  Venera 4 arrived at Venus on October 18, 1967. This was the first probe to be placed directly into the atmosphere and to return atmospheric data. It showed that the atmosphere was 90-95% carbon dioxide. It detected no nitrogen. The surface temperature reading was 500°C and pressure reading was 75 bar. It was crushed by the pressure on Venus before it reached the surface.
• Mariner 5 - USA Venus Flyby - 244 kg - (Jun 14, 1967)
  Mariner 5 arrived at Venus on October 19, 1967 one day after Venera 4. It passed within 3900 km of the planet's surface. It studied the Venusian magnetic field and found that its atmosphere was composed of 85-99% carbon dioxide. It is now in a solar orbit.
• Explorer 35 - USA Lunar Orbiter - 104 kg - (Jul 19, 1967 - 1972)
  Lunar orbiter acquired field and particle data.
• Surveyor 4 - USA Lunar Soft Lander - 283 kg - (Jul 14, 1967)
  Lander failed and impacted the moon.
• Lunar Orbiter 5 - USA Lunar Orbiter - 389 kg (Aug 1, 1967)
  Orbited the moon at a polar inclination, took high resolution pictures of many important sites and impacted on command.
• Surveyor 5 - USA Lunar Soft Lander - 279 kg - (Sep 8, 1967)
  Landed on the lunar surface.
• Surveyor 6 - USA Lunar Soft Lander - 280 kg - (Nov 7, 1967)
  Landed on and took off from the lunar surface.
• Pioneer 8 - USA Solar Probe - 63 kg - (Dec 13, 1967 - Present)
  Solar probe in solar orbit is still transmitting.
• Surveyor 7 - USA Lunar Soft Lander - 1,036 kg - (Jan 7, 1968)
  Landed on the lunar surface.
• Luna 14 - USSR Lunar Probe - 1,700 kg - (Apr 7, 1968)
  Luna 14 is in a lunar-solar orbit.
• Zond 5 - USSR Lunar Flyby - 5,375 kg - (Sep 14, 1968)
  Lunar fly-around and earth return.
• Pioneer 9 - USA Solar Probe - 63 kg - (Nov 8, 1968 - Mar 3, 1987)
  In solar orbit. Died on March 3, 1987.
• Zond 6 - USSR Lunar Flyby - 5,375 - (Nov 10, 1968)
  Lunar fly-around and earth return.
• Apollo 8 - USA Lunar Manned Orbiter - 28,883 kg - (Dec 21, 1968)
  First manned lunar fly-around and Earth return.
• Venera 5 - USSR Venus Atmosphere Probe - 1,128 kg - (Jan 5, 1969)
  Venera 5 arrived at Venus on May 16, 1969. Along with Venera 6, atmospheric data was returned indicating an atmosphere composed of 93-97% carbon dioxide, 2-5% nitrogen, and less than 4% oxygen. The probe returned data down to within 26 km of surface and was then lost - crushed by the pressure on Venus.
• Venera 6 - USSR Venus Atmosphere Probe - 1,128 kg - (Jan 10, 1969)
  Venera 6 arrived at Venus on May 17, 1969. Along with Venera 5, atmospheric data was returned indicating an atmosphere composed of 93-97% carbon dioxide, 2-5% nitrogen, and less than 4% oxygen. The probe returned data down to within 11 km of surface and was then lost - crushed by the pressure on Venus.
• Mariner 6 - USA Mars Flyby - 412 kg - (Feb 24, 1969)
  Mariner 6 arrived at Mars on February 24, 1969 and passed within 3437 km of the planet's equatorial region. Mariner 6 and 7 took measurements of the surface and atmospheric temperature, surface molecular composition and pressure of the atmosphere. In addition, over 200 pictures were taken. Mariner 6 is now in a solar orbit.
• Mariner 7 - USA Mars Flyby - 412 kg - (Mar 27, 1969)
  Mariner 7 arrived at Mars on August 5, 1969 and passed within 3551 km of the planet's south pole region. Mariner 6 and 7 took measurements of the surface and atmospheric temperature, surface molecular composition and pressure of the atmosphere. In addition, over 200 pictures were taken. Mariner 7 is now in a solar orbit.
• Apollo 10 - USA Lunar Manned Orbiter - 42,530 kg - (May 18, 1969)
  Manned lunar fly-around and Earth return. Tested the Lunar Module which separated from the Command and Service Module and descended to within 50,000 feet of the lunar surface. Acquired a large number of excellent 70-mm photographs.
• Luna 15 - USSR Lunar Lander - 2,718 kg - (Jul 13, 1969)
  Unsuccessful sample return attempt. Crashed during landing.
• Apollo 11 - USA Lunar Manned Lander - 43,811 kg - (Jul 16, 1969)
  Apollo 11 was the first manned lunar landing which took place on July 20, 1969. The landing site was Mare Tranquillitatis at latitude 0°67' N and longitude 23°49' E. Samples amounting to 21.7 kg were returned from the moon.
• Zond 7 - USSR Lunar Flyby - 5,979 kg - (Aug 8, 1969)
  Lunar fly-around and Earth return.
• Apollo 12 - USA Lunar Manned Lander - 43,848 kg - (Nov 14, 1969)
  Apollo 12 was a manned lunar landing which took place on November 19, 1969. The landing site was Oceanus Procellarum at latitude 3°12' S and longitude 23°23' W. This was the landing site for Surveyor 3. Portions of Surveyor 3 were retrieved includeing the camera. Samples amounting to 34.4 kg were returned from the moon.
• Apollo 13 - USA Lunar Flyby - 43,924 kg - (Apr 11, 1969)
  The Apollo 13 mission became one of survival for the astronauts on board. During the translunar coast an explosion destroyed both power and propulsion systems of the Command Service Module. The Lunar Module was used as a lifeboat to return safely home.
• Venera 7 - USSR Venus Lander - 1180 kg - (Aug 17, 1970)
  Venera 7 arrived at Venus on December 15, 1970 and was the first successful landing of a spacecraft on another planet. It used an external cooling device which allowed it to send back 23 minutes of data. The surface temperature was 475°C and surface pressure was 90 bar.
• Luna 16 - USSR Lunar Lander - 5,600 kg - (Sep 12, 1970)
  Landed on September 20, 1970 at Mare Fecunditaits located at latitude 0°41' S and longitude 56°18' E. 100 gm of lunar samples were returned to the Earth.
• Luna 17 - USSR Lunar Lander and Rover - 5,600 - (Nov 10, 1970 - 1971)
  Made lunar landing with an automated Lunokhod 1 Rover.
• Apollo 14 - USA Lunar Manned Lander - 44,456 kg - (Jan 31, 1971)
  Landed on the moon on Feb 5, 1971 at Fra Mauro located at 3°40' S and longitude 17°28' E. 42.9 kg of lunar samples were returned.
• Mariner 8 - USA Flyby - (May 8, 1971)
  Failed to reach Earth orbit.
• Kosmos 419 - USSR Probe - (May 10, 1971)
  Failed to leave Earth orbit.
• Mars 2 - USSR Orbiter/Soft Lander - 4,650 kg - (May 19, 1971)
  The Mars 2 lander was released from the orbiter on November 27, 1971. It crashed-landed because its breaking rockets failed - no data was returned and the first human artifact was created on Mars. The orbiter returned data until 1972.
• Mars 3 - USSR Orbiter/Soft Lander - 4,643 kg - (May 28, 1971)
  Mars 3 arrived at Mars on December 2, 1971. The lander was released and became first successful landing on Mars. It failed after relaying 20 seconds of video data to the orbiter. The Mars 3 orbiter returned data until Aug 1972. It made measurements of surface temperature and atmospheric composition.
• Mariner 9 - USA Mars Orbiter - 974 kg - (May 30, 1971 - 1972)
  Mariner 9 arrived at Mars on November 3, 1971 and was placed into orbit on the 24th. This was the first US spacecraft to enter an orbit around a planet other than the Moon. At the time of its arrival a hugh dust storm was in progress on the planet. Many of the scientific expirements were delayed until the storm had subsided. The first hi-resolution images of the moons Phobos and Deimos were taken. River and channel like features were discovered. Mariner 9 is still in a Mars orbit.
• Apollo 15 - USA Lunar Manned Lander - 46,723 kg - (Jul 26, 1971)
  Landed on the moon on Jul 30, 1971. The landing site was Hadley-Apennine at latitude 26°6' N and longitude 3°39' E. Samples amounting to 76.8 kg were returned from the moon. A lunar Roving Vehicle was carried on this mission which allowed the astronauts to travel several kilometers from the landing site.
• Luna 18 - USSR Lunar Lander - 5,600 kg - (Sep 2, 1971 - 1972)
  Unsuccessful sample return attempt. Crashed during landing.
• Luna 19 - USSR Lunar Orbiter - 5,600 kg - (Sep 28, 1971 - 1972)
  The orbiter is now an a lunar orbit.
• Luna 20 - USSR Lunar Lander - 5,600 kg - (Feb 14, 1972)
  Landed on the moon and returned samples to the Earth. Landed on February 21, 1972 at Apollonius highlands located at latitude 3°32' N and longitude 56°33' E. 30 gm of lunar samples were returned to the Earth.
• Pioneer 10 - USA Jupiter Flyby - 259 kg - (Mar 3, 1972)
  Pioneer 10 flew by Jupiter on December 1, 1973. It passed 132,250 km from Jupiter's cloud tops. It returned over 500 images of Jupiter and its moon. Its greatest achievement was the date collected on Jupiter's magnetic field, trapped charged particles and solar wind interactions. The orbit boundry of Pluto was crossed on Jun 13, 1983 it has now left the solar system.
• Venera 8 - USSR Venus Lander - 1,180 kg - (Mar 27, 1972)
  Venera 8 arrived at Venus on July 22, 1972. It measure wind speed variations as it descended through the atmosphere: 100 m/s above 48 km, 40-47 m/s at 42-48 km, and 1 m/s below 10 km. It returned data for 50 minutes.
• Apollo 16 - USA Manned Lunar Lander - 46,733 kg - (Apr 16, 1972)
  Landed on the moon on Apr 21, 1972 at the Descartes crater located at latitude 9°00' N and longitude 15°31' E. 94.7 kg of lunar samples were returned.
• Apollo 17 - USA Manned Lunar Lander - 46,743 kg - (Dec 7, 1972)
  Landed on the moon on Dec 12, 1972. The landing site was Taurus-Littrow at latitude 20°10' N and longitude 30°46' E. Samples amounting to 110.5 kg were returned from the moon.
• Luna 21 - USAR Lunar Lander and Rover - 4,850 kg - (Jan 8, 1973)
  Made lunar landing with an automated Lunokhod 2 Rover.
• Pioneer 11 - USA Flyby - 259 kg - (Apr 6, 1973)
  Pioneer 11 flew by Jupiter on December 1, 1974 passing 42,900 km from Jupiter's cloud tops. It took better pictures than Pioneer 10 and measured Jupiter's intense charged-particle and magnet field environment. As it flew by Jupiter it was given a gravity assist which swung it onto a course for Saturn. On September 1, 1979, Pioneer 11 flew past the outer edge of Saturn's A ring at a range of 3500 km. It traveled underneath the ring system and passed 20,930 km from Saturn's cloud tops. It has now left the solar system.
• Explorer 49 - USA Solar Probe - 328 kg - (Jun 10, 1973)
  Solar physics probe placed in lunar orbit.
• Mars 4 - USSR Mars Orbiter - 4,650 kg - (Jul 21, 1973)
  Mars 4 arrived at Mars in February, 1974, but failed to go into orbit due to a malfunction of its breaking engine. It flew past the planet with in 2200 km of the surface. It returned some images and data.
• Mars 5 - USSR Mars Orbiter - 4,650 kg - (Jul 25, 1973)
  Mars 5 entered into orbit around Mars on February 12, 1974. It acquired imaging data for the Mars 6 and 7 missions.
• Mars 6 - USSR Mars Orbiter/Soft Lander - 4,650 kg - (Aug 5, 1973)
  On March 12, 1974, Mars 6 entered into orbit and launched its lander. The lander returned atmospheric descent data but failed on its way down.
• Mars 7 - USSR Mars Orbiter/Soft Lander - 4,650 kg - (Aug 9, 1973)
  On March 6, 1974, Mars 7 failed to go into orbit about Mars and the lander missed the planet. Carrier and lander are now in a solar orbit.
• Mariner 10 - USA Lunar Flyby - 526 kg - (Nov 3, 1973)
  Mariner 10 was the first dual planet mission. It flew past Venus on February 5, 1974 in a gravity assist to the planet Mercury. Mariner 10 was the first spacecraft to have an imaging system. It recorded circulation in the Venusian atmosphere and showed the temperature of the cloud tops to be -23°C. Mariner 10 flew past Mercury 3 times on March 29, 1964, September 21, 1974 and March 16, 1975. These three encounters produced over 10,000 pictures with 57% planet coverage. It recorded surface temperatures ranging from 187°C to -183°C on the day and night sides. A weak magnetic field was detected but it failed to detect an atmosphere. Mariner 10 is now in a solar orbit.
• Luna 22 - USSR Lunar Orbiter - 5,600 kg - (May 29, 1974 - 1975)
  Successfully entered lunar orbit.
• Luna 23 - USSR Lunar Probe - 5,6000 kg - (Oct 28, 1974)
  Crashed on the lunar surface.
• Helios - USA & West Germany Solar Probe - 370 kg - (Dec 10, 1974 - 1975)
  Solar probe is in a solar orbit.
• Venera 9 - USSR Venus Orbiter and Lander - 4,936 kg (Jun 8, 1975)
  Venera 9 arrived at Venus on October 22, 1975 three days before its sister spacecraft Venera 10. Both orbiters photographed the clouds and looked at the upper atmosphere. Differences in cloud layers was discovered at 57-70 km, 52-57 km and 49-52 km from the surface. The lander arrived on the Venusian surface on November 22, 1975. During a period of about an hour, it transmitted the first black and white images of the planets surface. It showed sharp-edged flat rocks and a basaltic terrain. The probe in now in a Venus orbit.
• Venera 10 - USSR Venus Orbiter and Lander - 5,033 kg - (Jun 14, 1975)
  Venera 10 arrived at Venus on October 25, 1975 three days after its sister spacecraft Venera 9. Both orbiters photographed the clouds and looked at the upper atmosphere. Differences in cloud layers was discovered at 57-70 km, 52-57 km and 49-52 km from the surface. The lander arrived on the Venusian surface on November 25, 1975. During a period of 65 minutes, it transmitted black and white images of the planets surface. The terrian was more eroded than at the Venera 9 landing site.
• Viking 1 - USA Orbiter/Lander - 3,399 kg - (Aug 20, 1975 - August 7, 1980)
  Viking 1 and 2 were designed after the Mariner spacecraft. They consisted of an orbiter and lander. The orbiter weighed 900 kg and the lander 600 kg. Viking 1 went into orbit about Mars on June 19, 1976. The lander touched down on July 20, 1976 on the western slopes of Chryse Planitia. Both landers had expirements to search for Martian micro-organism. The results of these expirements are still being debated. The landers provided detailed color panoramic views of the Martian terrain. They also monitered the Martian weather. The orbiters mapped the planet's surface acquiring over 52,000 images. Viking 1 orbiter was deactivate on August 7, 1980 when it ran out of altitude-control propellant. Viking 1 lander was accidentally shut down on November 13, 1982 and communication was never regained.
• Viking 2 - USA Orbiter/Lander - 3,399 kg - (Sep 9, 1975 - July 25, 1978)
  Viking 1 and 2 were designed after the Mariner spacecraft. They consisted of an orbiter and lander. The orbiter weighed 900 kg and the lander 600 kg. Viking 2 went into orbit about Mars on July 24, 1976. The lander touched down on August 7, 1976 at Utopia Planitia. Both landers had expirements to search for Martian micro-organism. The results of these expirements are still being debated. The landers provided detailed color panoramic views of the Martian terrain. They also monitered the Martian weather. The orbiters mapped the planet's surface acquiring over 52,000 images. Viking 2 orbiter was deactivate on July 25, 1978 when it ran out of altitude-control propellant. Viking 2 lander used Viking 1 orbiter as a communications relay and had to be shut down at the same time as the orbiter on August 7, 1980.
• Luna 24 - USSR Lunar Lander - 4,800 kg - (Aug 9, 1976)
  The landing site was Mare Crisium at latitude 12°45' N and longitude 60°12' E. Samples amounting to 170 gm were returned from the moon.
• Voyager 1 - USA Flyby - 800 kg - (Sep 5, 1977)
  Voyager 1 flew by Jupiter on March 5, 1979 and Saturn on November 12, 1980.
• Voyager 2 - USA Flyby - 800 kg - (Aug 20, 1977)
  Voyager 2 flew by Jupiter on July 9, 1979, Saturn on August 26, 1981, Uranus on January 24, 1986, and Neptune on August 24, 1989.
• Pioneer Venus 1 - USA Orbiter - 582 kg - (May 20, 1978 - 1992)
  Pioneer Venus 1 (also known as Pioneer 12) arrived at Venus on December 4, 1978. It operated continuously from 1978 until October 8, 1992 when contact was lost with the spacecraft. It was expected to burn up in the Venusian atmosphere 6 days later. The orbiter was the first spacecraft to use radar in mapping the planet's surface. The electron field expirement detected radio bursts presumably caused by lightening. No magnetic field was detected. From 1978 to 1988 the amount of sulfur dioxide in the atmosphere decreased by 10%. The reason for this decrease is unknown. Perhaps a large volcano errupted just before the orbiter arrived and the amout of sulfur dioxide slowly declined.
• Pioneer Venus 2 - USA Atmosphere Probe - 904 kg - (Aug 8, 1978)
  Pioneer Venus 2 (also know as Pioneer 13) carried four atmospheric probes. One large and three smaller ones. They arrived at Venus on December 9, 1978 and plunged into the atmosphere. The four probes descended through the atmosphere by parachute while the spacecraft burned up high in the atmosphere. At a height of 70-90 km the probes encountered a fine haze layer. Between 10-50 km there was little atmospheric convection and below 30 km the atmosphere was clear.
• International Sun-Earth Explorer 3 - USA - 479 kg - (Aug 12, 1978)
  The Internation Sun-Earth Explorer was renamed to International Cometary Explorer (ICE). On September 11, 1985 it passed through the plasma tail of comet Giacobini-Zinner.
• Venera 11 - USSR Venus Flyby/Lander - 4,940 kg - (Sep 9, 1978)
  Venera 11 landed on Venus on December 25, 1978 and returned data for 95 minutes. The imaging systems failed.
• Venera 12 - USSR Venus Flyby/Lander - 4,940 kg - (Sep 14, 1978)
  Venera 12 landed on December 21, 1978 and returned data for 110 minutes. Electrical discharges, probably from lightning, were recorded.
• Venera 13 - USSR Venus Flyby/Lander - 5,000 kg - (Oct 30, 1981)
  Venera 13 landed on Venus on March 1, 1982. It returned black and white, and the first color panoramic views of the Venusian surface. It also conducted soil analysis using an x-ray fluorescence spectrometer. The sample was determined to be leucite basalt a rare rock type on the Earth.
• Venera 14 - USSR Venus Flyby/Lander - 5,000 kg - (Nov 4, 1981)
  Venera 14 landed on Venus on March 5, 1982. It returned black and white, and color panoramic views of the Venusian surface. It also conducted soil analysis using an x-ray fluorescence spectrometer. The sample was determined to be tholeiitic basalt similar to that found at mid-ocean ridges on the Earth.
• Venera 15 - USSR Venus Orbiter - 5,000 kg - (Jun 2, 1983)
  Venera 15 arrived at Venus on October 10, 1983. Its high-resolution imaging system produced images of 1-2 km in resolution. Verera 15 and 16 produced a map of the nother hemisphere from the pole to 30°N. They found several hot spots, possibly caused from volcanic activity.
• Venera 16 - USSR Venus Orbiter - 5,000 kg - (Jun 7, 1983)
  Venera 16 arrived at Venus on October 14, 1983. Its high-resolution imaging system produced images of 1-2 km in resolution. Verera 15 and 16 produced a map of the nother hemisphere from the pole to 30°N. They found several hot spots, possibly caused from volcanic activity.
• Vega 1 - USSR Venus/Comet Halley Flyby - 4,000 kg - (Dec 15, 1984)
  Vega 1 flew past Venus on June 11, 1985 on its way for a flyby with comet Halley. It dropped off a Venera style lander and a balloon to investigate the Venusian middle cloud layer. The lander's soil expirement failed. The balloon floated in the atmosphere for about 48 hours at an altitude of 54 km. Between Vega 1 and 2, downward gusts of 1 m/s were encountered and wind velocities of up to 240 km/s. The Comet Halley flyby took place on Mar 6, 1986. The Vega 1 probe is now in a solar orbit.
• Vega 2 - USSR Venus/Comet Halley Probe - 4,000 kg - (Dec 21, 1984)
  Vega 2 flew past Venus on June 15, 1985 on its way for a flyby with comet Halley. It dropped off a Venera style lander and a balloon to investigate the Venusian middle cloud layer. The lander's soil expirement sampled anorthosite-troctolite which is found in the lunar highlands but is rare on Earth. The balloon floated in the atmosphere for about 48 hours at an altitude of 54 km. Between Vega 1 and 2, downward gusts of 1 m/s were encountered and wind velocities of up to 240 km/s. The Comet Halley flyby took place on Mar 9, 1986. The Vega 2 probe is now in a solar orbit.
• Sakigake - Japan - 141 kg - (Jan 7, 1985)
  Comet Halley flyby took place on Mar 1, 1986.
• Giotto - Europe - 512 kg - (Jul 2, 1985)
  Comet Halley flyby took place on Mar 13, 1986. After the Halley fly-by, Giotto was put into hibernation, and re-awoken in 1990. Using a close Earth flyby, its trajectory was changed to allow a close encounter with the Comet Grigg-Skjellerup on July 10th, 1992. The flyby distance was actually less than that at Halley (around 200km from the nucleus).
• Suisei - Japan - 141 kg - (Aug 18, 1985)
  Comet Halley flyby took place on Mar 8, 1986.
• Phobos 1 - USSR Orbiter/Lander - 5,000 kg - (Jul 7, 1988)
  Phobos 1 was sent to investigate the Martian moon Phobos. It was lost en route to Mars through a command error on September 2, 1988.
• Phobos 2 - USSR Orbiter/Lander - 5,000 kg - (Jul 12, 1988)
  Phobos 2 arrived at Mars and was inserted into orbit on January 30, 1989. The orbiter moved within 800 km of Phobos and then failed. The lander never made it to Phobos.
• Magellan - USA Orbiter - 3,545 kg - (May 4, 1989 - 1994)
  Magellan was released into Earth's orbit from a space shuttle and then injected into a transer orbit to Venus by an upper stage. Its primary mission was to map Venus using synthetic aperture radar. The surface of Venus is obscured by thick clouds of carbon dioxide that makes the suface invisible to optical instruments. It arrived at Venus on August 10, 1990. Its radar imaging system was able to produce images at 300 meters resolution.
• Galileo - USA & Europe Flybys - 2,222 kg - (Oct 18, 1989)
  Galileo was designed to study Jupiter's atmosphere, satellites and surrounding magnetosphere for 2 years. In order to get there, it used gravity assist techniques to pick up speed by flying by Venus on February 10, 1990. It then flew by the Earth & Moon twice. The first was on December 8, 1990 and the second December 8, 1992. It has made encounters asteroid 951 Gaspra on October 29, 1991 and asteroid 243 Ida on August 28, 1993.
• Muses-A - Japan Lunar Orbiters - (1990)
  This consisted of two small orbiters but failed to send back data from their orbit around the Moon. This was the first non USA or USSR probe to reach Moon.
• Ulysses - USA & Europe Solar Flyby - 370 kg - (Oct 6, 1990)
  The Ulysses spacecraft is an international project to study the poles of the Sun and interstellar space above and below the poles. It used Jupiter as a gravity assit to swing out of the ecliptic plane and onward to the poles of the Sun. The Jupiter flyby was on February 8, 1992. The first solar polar passage will be in June 1994 and the spacecraft will pass the solar equator in February 1995.
• Mars Observer - USA Mars Orbiter (Sep 25, 1992)
  Communication was lost with Mars Observer on August 21, 1993 just before it was to be inserted into orbit.
• Clementine - USA Lunar Orbiter - (1994)
• Mars Global Surveyor - USA Orbiter (Fall 1996)
  The Mars Global Surveyor is scheduled for launch in the late fall of 1996. It was initiated due to the loss of the Mars Observer. The basic spacecraft design is after the Mars Observer.
• Pluto Express - USA Pluto Flyby - (2001)
  The Pluto Express mission is scheduled for launch around 2001 and arrive at Pluto around 2006-2008. The mission will consist of a pair of small, fast, relatively cheep spacecraft weighing less than 100 kg each. The spacecraft will pass within 15,000 km of Pluto and Charon.

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Copyright © 1995 by Calvin J. Hamilton. All rights reserved.
Last Modified: May 16, 1995