E-sail test payload of the ESTCube-1 nanosatellite

The scientific mission of ESTCube-1, launched in May 2013, is to measure the electric solar wind sail (E-sail) force in orbit. The experiment is planned to push forward the development of the E-sail, a propulsion method recently invented at the Finnish Meteorological Institute. The E-sail is based on extracting momentum from the solar wind plasma flow by using long thin electrically charged tethers. ESTCube-1 is equipped with one such tether, together with hardware capable of deploying and charging it. At the orbital altitude of ESTCube-1 there is no solar wind present. Instead, ESTCube-1 shall observe the interaction between the charged tether and the ionospheric plasma. The ESTCube-1 payload uses a 10-m, partly two-filament E-sail tether and a motorized reel on which it is stored. The tether shall be deployed from a spinning satellite with the help of centrifugal force.During the E-sail experiment the tether shall be charged to 500 V potential. Both positive and negative voltages shall be experimented with.