Future satellite systems must survive in the space environment for 5 to 10 years to achieve greater cost effectiveness. Characterization of the orbital space environment and effects on spacecraft systems have received considerable attention recently years. Instrumentation has been developed by Physical Sciences Inc., under Ballistic Missile Defense Office (BMDO) sponsorship, for long-term measurement of key physical parameters characterizing the low Earth orbit (LEO) environment and its effects on degradation of spacecraft materials and solar arrays. These measurements enable active, real-time monitoring of the health of spacecraft and payload systems. SAMMES is designed to be autonomous, compact, low power, and lightweight.