PMU Computer, Iridium Communications Satellite

Radio waves from a mobile phone are received by an Iridium satellite, converted to digital "packets," routed according to destination, and then reconverted to radio signals for transmission. A series of computers perform this work as well as operate the satellite. Four computers like this one, dubbed a "smart modem," manage the flow of signals among the satellite's various antennas. This onboard computing power contrasts with traditional communications satellites, which generally receive and transmit radio signals without digitally processing them.

Motorola Space and Systems Technology Group, Satellites Communications Division, the manufacturer, donated this artifact to the Museum in 1998.