Solar Anomalous and Magnetospheric Particle Explorer

The Solar Anomalous and Magnetospheric Particle Explorer (SAMPEX or Explorer 68) was a NASA solar and magnetospheric observatory and was the first spacecraft in the Small Explorer program. It was launched into low Earth orbit on 3 July 1992 from Vandenberg Air Force Base (Western Test Range) aboard a Scout G-1 launch vehicle. SAMPEX was an international collaboration between NASA and the Max Planck Institute for Extraterrestrial Physics of Germany (which provided the Heavy Ion Large Telescope). The Solar Anomalous and Magnetospheric Particle Explorer (SAMPEX) is the first of a series of spacecraft that was launched under the Small Explorer (SMEX) program for low-cost spacecraft.

Mission

The main objectives of SAMPEX experiments were to obtain data for several continuous years on the anomalous components of cosmic rays, on solar energetic particle emission from the Sun, and on the precipitating magnetospheric relativistic electrons. The orbit of SAMPEX has an altitude of 520 × 670 km (320 × 420 mi) and an 82 deg inclination. The spacecraft uses an onboard 3-axis stabilized solar-pointed/momentum bias system with the pitch axis pointed toward the Sun. Solar panels provide power for operations, including 16.7 watts for science instruments. An on-board Data processing unit (DPU) preprocesses the science and other data and stores them in a Recorder/Processor/Packetizer (RPP) unit of about 65 Mb, before transmitting in the S-band at a rate of 1.5 Mbit/s over Wallops Flight Facility (WFF) (or a back-up) station. The command memory can store at least a thousand commands.