Propulsive Small Expendable Deployer System experiment

Relatively short electrodynamic tethers can extract orbital energy to "push " against a planetary magnetic field to achieve propulsion without the expe nditure of propellant. The Propulsive Small Expendable Deployer System expe riment will use the flight-proven Small Expendable Deployer System to deplo y a 5-km bare aluminum tether from a Delta II upper stage to achieve approx imate to 0.4-N drag thrust, thus lowering the altitude of the stage. The ex periment will use a predominantly bare tether for current collection in lie n of the endmass collector and insulated tether used on previous missions. The flight experiment is a precursor to a more ambitious electrodynamic tet her upper-stage demonstration mission that will be capable of orbit-raising , -lowering, and inclination changes, all using electrodynamic thrust. The expected performance of the tether propulsion system during the experiment is described.