Scientist Sells the Electric Sail for Space Propulsion

Whisper-thin charged wires form a low-power sail for the solar wind

3 min read

13 May 2008—Next week, scientists will gather at the European Space Research and Technology Centre (ESTEC) in Noordwijk, the Netherlands, to discuss a radical idea in spacecraft propulsion. A Finnish invention known as an electric sail has been designed to propel a space probe through the solar system by repelling the protons contained in the solar wind. If successful, the electric sail would reduce the cost of launching deep-space probes that must carry heavy fuel tanks.

Invented by Pekka Janhunen, a research fellow at the Finnish Meteorological Institute, the electric sail produces thrust from the solar wind, comprising high-energy electrons and protons streaming from the sun. The electric sail is similar in some ways to the more conventional solar-sail idea. The solar sail requires a ultrathin aluminized Mylar sail 250 meters in diameter to catch the solar wind, which blows out from the sun at speeds between 400 and 800 kilometers per second. However, no one has ever deployed and tested the solar sail in space, and because of its extreme size, the sail presents a number of engineering problems. But, says Janhunen, the electric sail has many advantages over the solar sail—notably, not having to deploy a gigantic sheet of Mylar in space.

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Top Tech 2023: A Special Report

These two dozen technical projects should make significant advances in the coming year

2 min read
Top Tech 2023: A Special Report
Edmon DeHaro

Each January, the editors of IEEE Spectrum offer up some predictions about technical developments we expect to be in the news over the coming year. You’ll find a couple dozen of those described in the following special report. Of course, the number of things we could have written about is far higher, so we had to be selective in picking which projects to feature. And we’re not ashamed to admit, gee-whiz appeal often shaped our choices.

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