P 11-AS was a polar-orbiting Air Force scientific satellite that carried six experiments. Instrumentation on board included spectrometers and Geiger tubes to measure electrons and protons in various energy ranges (both directional and omnidirectional experiments), a Faraday cup, a VLF experiment, and a magnetometer. The spacecraft spin axis was approximately aligned with the earth's spin axis. Telemetry consisted of two tape-recorded and two real-time data channels. Each of two commutators had one real-time and one tape-recorded channel. Two weeks after launch one of the commutators temporarily stopped and thereafter operated intermittently. Four weeks later, the tape-recorded channel on the other commutator failed. On September 1, 1965, the tape recorder failed, and very little scientific data were obtained after that date.