Galileo robotic probe retro propulsion module check/test assembly, measuring approximately 19″ x 26″ x 18.5″, marked on the faceplate: "Galileo - RPM, Electrical Test Unit (ETU), MBB 9900-1." The front panels have numerous switches and knobs dedicated to testing various aspects of the Galileo's retro propulsion module, with areas labeled "ISO Latch Valves," "400 N REA," "10 N Thrusters," "Automatic Shut-Off," "Resistances," "Pressure Transducers," "Temperature Sensors," and "All Functions." The upper panel has a diagram of the circuit board, with areas marked "PCA-1," "PCA-2," "PIA-1," "PIA-2," "Cluster 2 (-X)," and "Cluster 1 (-X)." Includes several peripherals such as data cables, patch panels, and the original power cord. In overall very good to fine condition. Delivered into Earth orbit by the Space Shuttle Atlantis in 1989, Galileo became the first spacecraft to orbit Jupiter in 1995.