SAMPEX is the first of SMEX'es (SMall EXplorers). SAMPEX was launched in July 1992 from Western Test Range (Lompoc,CA) at 1419 UT on July 3, 1992. SAMPEX orbits at an altitude 520 by 670 Km and 82 ... degrees inclination and carries four instruments on board. SAMPEX measures energetic electrons as well as ion composition of particle populations from ~0.4 MeV/nucleon to hundreds of MeV/nucleon from a zenith-oriented satellite in a near polar orbit. The Payload combines some of the most sensitive particle sensors ever flown in space.
Information provided by http://lasp.colorado.edu/sampex/sampex.html