One of the biggest constraints on exploration of the solar system is fuel. Spacecraft need fuel to get where they’re going, and they need even more fuel in order to do what they’re supposed to do once they arrive. Though energy (electricity) can be replenished for years (or even decades) with solar panels or RTGs, once you run out of reaction mass, your spacecraft is through. (If you’re smart, you’ll have suicided it into something well before then.)

Propulsion systems like ion engines and electrospray engines can use small amounts of fuel very efficiently, but only postpones the problem of limited reaction mass as opposed to solving it. Fortunately, some very smart people are working on alternative means of fuel-free propulsion; one of the least crazy ones has been funded NASA as part of its Innovative Advanced Concepts Program. It’s called E-Glider, and it uses electrostatic fields to surf through the charged dust found around asteroids, comets, and moons.

Around airless bodies, the objects in space that range in size from asteroids to either small moons or large space stations, you can reliably find a sort of haze of dust, caused by the solar wind as well as solar illumination imparting energy to the surface which results in dust particles “fountaining” up. This energy transfer also causes the dust to become electrically charged, with the illuminated side of the body exhibiting a positive surface potential and the dark side of the body accumulating electrons which results in a negative surface potential. The terminator (the area between the dark side and illuminated side) can have an electrical potential of several hundred kilovolts per meter,…[Read more]