Pioneer Program

The Pioneer probes were a series of disperate spacecraft in multiple programs visiting the moon, solar orbit, Venus, Jupiter, Saturn and the interstellar medium.

Pioneers 0, 1 and 2, designed by the Space Technology Laboratories (STL), were part of the Thor-Able launched space probes flying from 1958 to 1960. Intended for lunar orbit, all three failed. Pioneers P-1, P-3, P-30 and P-31 built by TRW equally unsuccesfully launched to orbit the moon. Of the Juno II launched JPL built Pioneers 3 and 4, no. 3 failed but no. 4 was the first US probe to escape Earth gravity and fly by the moon. Pioneer 5, or P-2 was the only Thor-Able launched Pioneer to reach its destination between Earth and Venus, altough it missed the window for its originally planned Venus flyby.

The next generation of Pioneer probes flew from 1965 to 1978. Pioneers 6 to 9 (A-E, with E lost in launch) were TRW built space weather probes orbiting between 0.75 and 1.2 AU from the sun. TRW built Pioneers 10 and 11 (F, G) launched in '72 and '73 with both visiting Jupiter, 11 visiting Saturn, and both leaving the heliosphere.

The Pioneer Venus project sent the Hughes built Pioneer Venus Orbiter (12) and the Pioneer Venus Multiprobe (13) to Venus in 1978. They arrived that same year, with the former entering orbit and the later deploying its four small probes and burning up in the atmosphere. The orbiter returned data up to 1992, and disintegrated upon entering the atmosphere.