2 The Pioneer 10 and 11 Project

NASA’s Pioneer program began in 1958, in the earliest days of the space age, with experimental spacecraft that were designed to reach Earth escape velocity and perform explorations of the interplanetary space beyond the Earth’s orbit. Several of these launch attempts ended in failure; the five spacecraft that reached space later became known as Pioneers 1 – 5. These were followed in the second half of the 1960s by Pioneers 6 – 9, a series of significantly more sophisticated spacecraft that were designed to be launched into solar orbit and make solar observations. These spacecraft proved extremely robust1 and paved the way for the most ambitious projects yet in the unmanned space program: Pioneers 10 and 11.

The Pioneer 10 and 11 spacecraft were the first two man-made objects designed to explore the outer solar system (see details in [294291Jump To The Next Citation Point293290292Jump To The Next Citation Point289Jump To The Next Citation Point162Jump To The Next Citation Point295286354285127126Jump To The Next Citation Point143272350Jump To The Next Citation Point296383385Jump To The Next Citation Point386Jump To The Next Citation Point]). Their objectives were to conduct, during the 1972 – 73 Jovian opportunities, exploratory investigation beyond the orbit of Mars of the interplanetary medium, the nature of the asteroid belt, the environmental and atmospheric characteristics of Jupiter and Saturn (for Pioneer 11), and investigate the solar system beyond Jupiter’s orbit.

In this section we review the Pioneer 10 and 11 missions. We present information about the spacecraft design. Our discussion focuses on subsystems that played important roles in the continued functioning of the vehicles and on subsystems that may have affected their dynamical behavior: specifically, we review the propulsion, attitude control, power, communication, and thermal subsystems. We also provide information about the history of these systems throughout the two spacecrafts’ exceptionally lengthy missions.

 2.1 The Pioneer 10 and 11 missions
  2.1.1 Pioneer 10 mission details
  2.1.2 Pioneer 11 mission details
  2.1.3 Pioneer 10 and 11 project documentation
 2.2 The Pioneer spacecraft
  2.2.1 General characteristics
  2.2.2 Science instruments
  2.2.3 Radioisotope thermoelectric generators (RTGs)
  2.2.4 The electrical subsystem
  2.2.5 Propulsion and attitude control
  2.2.6 Navigation
  2.2.7 Communication system
  2.2.8 Telemetry data and its interpretation
  2.2.9 Thermal subsystem
 2.3 Spacecraft operating history
  2.3.1 Spacecraft physical configuration
  2.3.2 Changes in spacecraft mass
  2.3.3 Instrumentation
  2.3.4 Electrical system
  2.3.5 Radioisotope thermoelectrical generators
  2.3.6 Propulsion system
  2.3.7 Attitude control and spin
 2.4 Thermal control subsystem
  2.4.1 Waste heat from the RTGs
  2.4.2 Electrical heat
  2.4.3 Radioisotope heater units
  2.4.4 Waste heat from the propulsion system
  2.4.5 The energy radiated in the radio beam
  2.4.6 Thermal measurements in the telemetry
  2.4.7 Surface radiometric properties and thermal behavior

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