Add to ORKGThe Electric Solar Wind Sail (E-sail) is a novel propulsion concept that enables faster space travel to many solar system targets. E-sail uses charged solar wind particles as the source of its propulsion. This is achieved by deploying long, conducting and charged tethers, which get pushed by the solar wind by Coulomb drag [1]. E-sail technology is being developed to technical readiness level (TRL) 4-5 by the European Union's Seventh Framework Programme for Research and Technological Development, EU FP7, in a project named ESAIL (http://www.electric-sailing.fi/fp7). Prototypes of the key parts are to be produced. The design will be scalable so that a real solar wind demonstration mission could be scaled up from them. We review here the lates...