Pioneer 6

Pioneer 6 was the first in a series of solar-orbiting, spin-stabilized, solar-cell and battery-powered satellites designed to obtain measurements on a continuing basis of interplanetary phenomena from widely separated points in space. Its experiments studied the positive ions and electrons in the solar wind, the interplanetary electron density (radio propagation experiment), solar and galactic cosmic rays, and the interplanetary magnetic field. Its main antenna was a high-gain directional antenna. Although the spacecraft has not been regularly tracked for science data return in recent years, a successful telemetry contact was made on 8 Dec. 2000 to celebrate 35 years of continuous operation since launch.