Pioneer program

The US Pioneer program of unmanned space missions was designed for planetary exploration. There were a number of such missions in the program, but the most notable were Pioneer 10 and Pioneer 11, which explored the outer planets and left the solar system. Both carry a golden plaque, depicting a man and a woman and information about the origin and the creators of the probes, should any extraterrestrials 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.'" [cite web
url = http://history.nasa.gov/SP-4402/ch3.htm#88
title = Origins of NASA Names
accessdate = 2006-10-16
work = NASA History
publisher = www.history.nasa.gov]

Early Pioneer missions

The earliest missions were attempts to achieve Earth's escape velocity, simply to show it was feasible and study the Moon. This included the first launch by NASA which was formed from the old NACA. These missions were carried out by the US Air Force and Army.

Able space probes (1958-1960)

:"Most missions here are listed with their most recognised name, and alternate names after in brackets."

*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), probe lost September 1959
*Pioneer P-3 (Atlas-Able 4, Atlas-Able 4B, Pioneer X) - Lunar probe, lost in launcher failure December 1959
*Pioneer 5 (Pioneer P-2, Thor-Able 4, Pioneer V) - interplanetary space between Earth and Venus, launched March 11, 1960 [cite web | url = http://www.hq.nasa.gov/office/pao/History/Timeline/1960.html | title = Aeronautics and Astronautics Chronology, 1960 | publisher = NASA]
*Pioneer P-30 (Atlas-Able 5A, Pioneer Y) - Lunar probe, failed to achieve lunar orbit September 1960
*Pioneer P-31 (Atlas-Able 5B, Pioneer Z) - Lunar probe, lost in upper stage failure December 1960

Juno II lunar probes (1958-1959)

*Pioneer 3 - Lunar flyby, missed Moon due to launcher failure December 1958
*Pioneer 4 - Lunar flyby, achieved Earth escape velocity, launched March 1959

Later Pioneer missions (1965-1978)

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 the inner solar system, before the bold flyby missions to Jupiter and Saturn. While successful, the missions returned much poorer images than the Voyagers five years later. In 1978, the end of the program saw a return to the inner solar system, with the Pioneer Venus Orbiter and Multiprobe, this time using orbital insertion rather than flyby missions.

The new missions were numbered from Pioneer 6 ("Alternate names in brackets").

Pioneer 6, 7, 8 and 9 - interplanetary space "weather network"

*Pioneer 6 (Pioneer A) - launched December 1965
*Pioneer 7 (Pioneer B) - launched August 1966
*Pioneer 8 (Pioneer C) - launched December 1967
*Pioneer 9 (Pioneer D) - launched November 1968 ("defunct. since 1983")
*Pioneer E - lost in launcher failure August 1969Pioneer 6 and Pioneer 9 are in solar orbits with 0.8 AU's 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's distance to the Sun. Their orbital periods are therefore slightly longer than Earth's.
Because they orbit the Sun on either side of the Earth's orbital path, some of them are, from time to time, 180° away from Earth. They can sense parts of the Sun several days before the Sun's rotation reveals it to ground based/earth orbiting observatories. If a powerful solar magnetic storm is born, they can warn Earth in advance.

Outer solar system missions

*Pioneer 10 (Pioneer F) - Jupiter, interstellar space, launched March 1972
*Pioneer 11 (Pioneer G) - Jupiter, Saturn, interstellar space, launched April 1973
*Pioneer H - identical to Pioneers 10 and 11, but never launched

Pioneer Venus project

*Pioneer Venus Orbiter (Pioneer Venus 1, Pioneer 12) - launched December 1978
*Pioneer Venus Multiprobe (Pioneer Venus 2, Pioneer 13) - launched August 1978
**Pioneer Venus Probe Bus - transport vehicle and upper atmosphere probe
**Pioneer Venus Large Probe - 300 kg parachuted probe
**Pioneer Venus North Probe - 75 kg parachuted probe
**Pioneer Venus Night Probe - 75 kg parachuted probe
**Pioneer Venus Day Probe - 75 kg parachuted probe

ee also

*Pioneer anomaly
*Timeline of Planetary Exploration
*Able space probes

External links

* [http://spaceprojects.arc.nasa.gov/Space_Projects/pioneer/PNhome.html Pioneer Program home page]
* [http://solarsystem.nasa.gov/missions/profile.cfm?MCode=Pioneer_Moon Pioneer (Moon) Program Page] by [http://solarsystem.nasa.gov NASA's Solar System Exploration]
* [http://www.nap.edu/books/0309090504/html/ Mark Wolverton's "The Depths of Space" online]
* [http://www.astronautix.com/lvs/thorable.htm Thor Able - Encyclopedia Astronautica]
* [http://www.tsgc.utexas.edu/archive/characterizations/pioneer10.html Pioneer 10 & 11 Abstract]

References