Radiation research / VLF plasma wave detection. Development of the octagonal Environmental Research Satellites, designed for piggyback launching from large primary mission vehicles. Ranging in mass from 0.7 to 45 kg, and carrying from 1 to 14 experiments, the ERS spacecraft provided an inexpensive, flexible vehicle capable of making scientific and engineering measurements in space. A major role of the ERS satellites was to act as a test bed to determine the reliability of improved components and subsystems destined for use in later generations of spacecraft. A unique feature of the system was its capability to function without a battery. The key to this advantage was the design which permited solar cells, fastened to all exterior surfaces of the vehicle, to maintain constant exposure of about 15 percent of the sun. The ERS was a small satellite, measuring in one version only 22 cm on a side and weighing 680 g; the larger version weighed 45 kg and was a 51 cm diameter cylinder. The 8-sided version was designated the OV-5 and became a part of a program conducted by the Air Force Office of Aerospace Research. Prime Contractor was TRW Systems Group of TRW Inc.

Materials research; deployed ERS 27. Space craft engaged in investigation of spaceflight techniques and technology (US Cat A).

Particle radiation data. Space craft engaged in investigation of spaceflight techniques and technology (US Cat A).

Space craft engaged in investigation of spaceflight techniques and technology (US Cat A).

• 2 - McDowell, Jonathan, The United Nations Registry of Space Objects, Harvard University, 1997. HTML when accessed: http://hea-www.harvard.edu/QEDT/jcm/space/un/un.html
• 6 - JPL Mission and Spacecraft Library, Jet Propulsion Laboratory, 1997. HTML when accessed: http://msl.jpl.nasa.gov/home.html
• 405 - Aerospace Yearbook, 1966, .