 A family portrait showing (from left to right)Pioneers 6-9, 10 and 11 and the Pioneer Venus Orbiter and Multiprobe series | |
| Program overview | |
|---|---|
| Country | United States |
| Organization | |
| Purpose | Lunar and interplanetary exploration |
| Status | Completed |
| Program history | |
| Duration |
|
| First flight | Pioneer 0 August 17, 1958 |
| Last flight | Pioneer Venus August 1978 |
| Successes | 9 |
| Failures | 10 |
| Partial failures | 1 |
| Launch site | Cape Canaveral Air Force Station |
| Vehicle information | |
| Launch vehicles | |
ThePioneer programs were two series ofUnited States lunar and planetaryspace probes. The first program, which ran from 1958 to 1960, unsuccessfully attempted to send spacecraft to orbit the Moon, successfully sent one spacecraft to fly by the Moon, and successfully sent one spacecraft to investigate interplanetary space between the orbits of Earth and Venus. The second program, which ran from 1965 to 1992, sent four spacecraft to measure interplanetaryspace weather, two to exploreJupiter andSaturn, and two to exploreVenus. The two outer planet probes,Pioneer 10 andPioneer 11, became the first two offive artificial objects to achieve theescape velocity that will allow them toleave the Solar System, and carrieda golden plaque each depicting a man and a woman and information about the origin and the creators of the probes, in case anyextraterrestrials find them someday.
Credit for naming the first probe has been attributed to Stephen A. Saliga, who had been assigned to the Air Force Orientation Group, Wright-Patterson AFB, as chief designer of Air Force exhibits. While he was at a briefing, the spacecraft was described to him, as, a "lunar-orbiting vehicle, with an infrared scanning device." Saliga thought the title too long, and lacked theme for an exhibit design. He suggested, "Pioneer", as the name of the probe, since "the Army had already launched and orbited the Explorer satellite, and their Public Information Office was identifying the Army, as, 'Pioneers in Space,'" and, by adopting the name, the Air Force would "make a 'quantum jump' as to who, really, [were] the 'Pioneers' in space.'"[1]
The earliest missions were attempts to achieve Earth'sescape velocity, simply to show it was feasible and to study theMoon. This included the first launch byNASA which was formed from the oldNACA. These missions were carried out by theAir Force Ballistic Missile Division,Army, and NASA.[2]
| Mission Name | Alternate Names | Type | Outcome | Date |
|---|---|---|---|---|
| Pioneer 0 | Thor-Able 1, Pioneer | Lunar orbiter | Destroyed (Thor failure 77 seconds after launch) | August 17, 1958 |
| Pioneer 1 | Thor-Able 2, Pioneer I | Lunar orbiter, missed Moon | Third stage partial failure | October 11, 1958 |
| Pioneer 2 | Thor-Able 3, Pioneer II | Lunar orbiter, reentry | Third stage failure | November 8, 1958 |
| Pioneer P-1 | Atlas-Able 4A, Pioneer W | Launch vehicle lost | September 24, 1959 | |
| Pioneer P-3 | Atlas-Able 4, Atlas-Able 4B, Pioneer X | Mission failed shortly after launch | November 26, 1959 | |
| Pioneer 5 | Pioneer P-2, Thor-Able 4, Pioneer V | March 11, 1960 | ||
| Pioneer P-30 | Atlas-Able 5A, Pioneer Y | Lunar probe | Failed to achieve lunar orbit | September 25, 1960 |
| Pioneer P-31 | Atlas-Able 5B, Pioneer Z | Lunar probe | Lost in upper stage failure | December 15, 1960 |
Five years after the early Able space probe missions ended,NASA Ames Research Center used the Pioneer name for a new series of missions, initially aimed at theinner Solar System, before the flyby missions toJupiter andSaturn. While successful, the missions returned much poorer images than theVoyager program probes would five years later. In 1978, the end of the program saw a return to the inner Solar System, with thePioneer Venus Orbiter andMultiprobe, this time using orbital insertion rather than flyby missions.
The new missions were numbered beginning with Pioneer 6 (alternate names in parentheses).
The spacecraft in Pioneer missions6, 7, 8, and 9 comprised a new interplanetaryspace weather network:
Pioneer 6 and Pioneer 9 are in solar orbits with 0.8AU distance to the Sun. Their orbital periods are therefore slightly shorter than Earth's. Pioneer 7 and Pioneer 8 are in solar orbits with 1.1 AU distance to the Sun. Their orbital periods are therefore slightly longer than Earth's. Since the probes' orbital periods differ from that of the Earth, from time to time, they face a side of the Sun that cannot be seen from Earth. The probes can sense parts of the Sun several days before the Sun's rotation reveals it to ground-based Earth orbiting observatories.
| Early missions |  | |
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| Later missions | ||
| Venus missions | ||
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| Moons |
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| Astronomy |
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| Exploration, orbital missions |
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