The Pioneer programs were two series of United States lunar and planetary space probes.The two outer planet probes, Pioneer 10 and Pioneer 11, became the first two of five artificial objects to achieve the escape velocity that will allow them to leave the Solar System, and carried a golden plaque each depicting a man and a woman and information about the origin and the creators of the probes, in case any extraterrestrials find them someday.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's escape velocity, simply to show it was feasible and to study the Moon.While successful, the missions returned much poorer images than the Voyager program probes would five years later.
Lunar flyby spacecraft (Pioneer 3, 4)
Pioneer P-1, P-3, 5, P-30, and P-31 probe
Pioneer
10 / 11
Map showing location and trajectories of the
Pioneer 10
(blue),
Pioneer 11
(green),
Voyager 1
(purple) and
Voyager 2
(red) spacecraft, as of April 4, 2007