Status report of the electric sail in 2009

The electric sail is a new propulsion concept which uses charged tethers to extract momentum from the solar wind by Coulomb interaction. We give a status report of the electric sail as of October 13, 2009. We report progress during the last two years in plasma physical thrust estimation, tether manufacture methods, navigability, test mission planning and applications. The thrust estimates have gone up recently by a factor of about five, samples of final-type tether have been manufactured, accurate navigability of the sail in variable solar wind has been shown numerically, a CubeSat test mission for measuring the electric sail force in orbit is in Phase-A study and trajectory calculations for many classes of missions have been made. Using existing technology, it seems possible to build an electric sail of ∼1N thrust, ∼100kg mass and ∼10 year lifetime. In terms of lifetime produced impulse per unit propulsion system mass, such a near-term and general-purpose device would be about 1000 times more efficient than a chemical rocket and about 100 times more efficient than a contemporary ion engine. This level of performance is enough to enable a host of important applications, such as in situ measurements in interstellar space, sample return from most solar system targets, non-Keplerian orbit probes for space weather forecasting and helioseismology and economical utilisation of asteroid resources.