Six Hydrazine thrusters provide velocity, attitude and spin-rate control. Pioneer 10 carries 11 instruments , and Pioneer 11 carries 12. Propellants are liquid oxygen and RP1. The Centaur second stage has two engines having a total thrust of 29,200 pounds. This engine carries insulation panels which are jettisoned just before the vehicle leaves the Earth's atmosphere and are used to prevent heat or air friction from causing boil-off of liquid hydrogen during flight through the atmosphere.
Propellant is liquid hydrogen and liquid oxygen.
This stage also spins the spacecraft up to 60 rpm. For further launch information, see NASA Lewis Pioneer 10 Silver Anniversary. The Pioneer 11 instruments are the same as the Pioneer 10 instruments, except that a Flux-Gate Magnetometer was added. As the spacecraft power continued to decline, instruments had to be turned off. By October 1995, none of the instruments could be operated, and the scientific investigations by Pioneer 11 came to an end.