PPCU (Partial Payload Checkout Unit)
P.C. Simons · IEEE Potentials · 1992
A description is given of the PPCU, a system used to verify the data and electrical interfaces of space shuttle payloads before forwarding them to integrated testing and, finally, to the space shuttle orbiter cargo bay. The system, which was built with off-the-shelf hardware and software, accomplishes this by simulating the electrical and data characteristics of the space shuttle's onboard interfaces. The function of each of the PPCU subsystems is explained, and the operation of the overall system is discussed.>