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.

Keep Reading ↓Show less

This article is for IEEE members only. Join IEEE to access our full archive.

Join the world’s largest professional organization devoted to engineering and applied sciences and get access to all of Spectrum’s articles, podcasts, and special reports. Learn more →

If you're already an IEEE member, please sign in to continue reading.

Membership includes:

  • Get unlimited access to IEEE Spectrum content
  • Follow your favorite topics to create a personalized feed of IEEE Spectrum content
  • Save Spectrum articles to read later
  • Network with other technology professionals
  • Establish a professional profile
  • Create a group to share and collaborate on projects
  • Discover IEEE events and activities
  • Join and participate in discussions
Two men fix metal rods to a gold-foiled satellite component in a warehouse/clean room environment

Technicians at Northrop Grumman Aerospace Systems facilities in Redondo Beach, Calif., work on a mockup of the JWST spacecraft bus—home of the observatory’s power, flight, data, and communications systems.


For a deep dive into the engineering behind the James Webb Space Telescope, see our collection of posts here.

When the James Webb Space Telescope (JWST) reveals its first images on 12 July, they will be the by-product of carefully crafted mirrors and scientific instruments. But all of its data-collecting prowess would be moot without the spacecraft’s communications subsystem.

The Webb’s comms aren’t flashy. Rather, the data and communication systems are designed to be incredibly, unquestionably dependable and reliable. And while some aspects of them are relatively new—it’s the first mission to use Ka-band frequencies for such high data rates so far from Earth, for example—above all else, JWST’s comms provide the foundation upon which JWST’s scientific endeavors sit.

Keep Reading ↓Show less