Pioneer 11

Telecommunications Description

The DSN supported the Pioneer spacecraft deep space tracking, uplink commands, and downlink data acquisition during the mission with 26-m, 34-m, 64-m, and 70-m antennas at Goldstone, Madrid, and Canberra. Overlapping coverage by two stations was used to prevent loss of data. The spacecraft carried three antennas for reception and transmission - low gain (omnidirectional), medium gain, and high gain (beamed) - with pairs of redundant transmitters and receivers, so the ground uplink and downlink DSN antennas could be switched between the different antenna sizes to accommodate telemetry demands from other missions. Downlink telemetry bit rates were at a maximum of 2048 bps enroute to Jupiter and 1024 bps at Jupiter but were maintained at 1024 bps out to Saturn's orbit due to increases in DSN antenna sensitivity. Reduced bit rates were required during superior conjunctions with the Sun. Pioneer 11 could receive uplink commands from 34-m antennas at 36 AU from the Sun in mid-1992, and the downlink could be maintained at 32 bps on the 70-mt antennas.