This is an engineering test model of a device flown aboard the Orbiting Geophysical Observatory (OGO) series of satellites, of which five were flown from 1964 through 1969. The device scanned and locked on to the Earth's horizon, by sensing infra-red radiation. It used that information to keep the satellite always pointing "down" (toward the center of the Earth), which was required for its mission. The devices were built by TRW Space Systems for the NASA Goddard Spaceflight Center, which managed the program.
NASA transferred this object to the Museum in 2007.
Gift of Bill Hibbard