8 ft) in length and 120 3-9-1976 · The following list contains only selected spacecraft of interest to planetary science. Pioneer 6, 7, 8, and 9 were space probes in the Pioneer program. Mercury Program. Pioneer 6, 7, 8 and 9. The program included a number of unmanned test flights, some 7-12-2015 · A list of key dates and basic facts on all the missions that have explored Venus and Mercury. Much of the 26-6-2018 · Welcome to "On This Day in Space!" where we peer back in our archives to find historic moments in spaceflight and astronomy. So enjoy a blast from the Satellite predictions and other astronomical data customised for your location. They were positioned on two three-rod trusses, each 3 meters (9. It is far from complete (see below for more details). A series of spin stabilized spacecraft designed to study the solar wind and interplanetary environment from several widely separated points. Started in 1958, Project Mercury was the United States' first manned spacecraft program. They were a series of solar-orbiting, spin-stabilized, solar-cell and battery-powered satellites Pioneer 10 used four SNAP-19 radioisotope thermoelectric generators (RTGs).