Propulsive Small Expendable Deployer System Experiment

Relatively short electrodynamic tethers can extract orbital energy to “ push” against a planetary magnetic e eld to achieve propulsion without the expenditure of propellant. The Propulsive Small Expendable Deployer System experiment will use the e ight-proven Small Expendable Deployer System to deploy a 5-km bare aluminum tether from a Delta II upper stage to achieve o 0.4-N drag thrust, thus lowering the altitude of the stage. The experiment willuseapredominantly baretetherforcurrentcollection in lieuoftheendmasscollectorandinsulated tetherused on previous missions. The e ight experiment is a precursor to a more ambitious electrodynamic tether 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.