Subsatellite studies of wave, plasma, and chemical injections from Spacelab

Three classes of Orbiter subsatellites have been identified to support Spacelab active plasma investigations: 1) small, throw-away detectors which are not reusable; 2) medium-sized, recoverable subsatellites, and 3) large, maneuverable subsatellites with a significant orbit-adjust capability. A class 1 subsatellite—the Plasma Diagnostics Package (POP)—was utilized attached to the Remote Manipulator System on the STS-3 flight to diagnose effects of the fast pulse electron generator electron beam and of Orbiter-produced plasma wakes. On the Spacelab-2 mission, the PDP will be released as a subsatellite to examine Orbiter wakes out to 20 km and the ionospheric plasma depletion effects resulting from planned Orbiter engine-burns. Class 1 Magnetospheric Multiprobes and a class 2 Recoverable Plasma Diagnostics Package are under development for the follow-on Spacelab missions. In addition, a study has been completed on a class 3 Solar-Terrestrial Subsatellite. All of these planned subsatellites provide measurements of plasma composition, wave fields, particle spectra, and optical emissions.