The Solar Anomalous and Magnetospheric Particle Explorer (SAMPEX) satellite was launched in July 1992 into a low earth orbit at an altitude of 520 by 670 km and 82 degrees inclination. The satellite far exceeded its expected three-year lifetime. It has primarily operated in a three-axis stabilized mode but has also been spun for limited periods. The satellite carries four instruments designed to measure the radiation environment of the Earth's magnetosphere.
SAMPEX was an international collaboration between NASA of the United States and Germany. It was part of the Small Explorer program started in 1989.