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Finnish Electric Solar Sail Nears Implementation

Posted by Soulskill on from the fly-me-to-the-moon dept.

eldavojohn writes "A recent meeting held by the Finnish Meteorological Institute has resulted in plans to build an electric solar sail that will circle the Earth, gaining speed to test its acceleration. The purpose? 'A flight out of the solar system to measure the gas, dust, plasma and magnetic field in the undisturbed interstellar space would perhaps be the "flagship" thing to do,' said Pekka Janhunen, a researcher developing the sail at the FMI. The details and papers of this project (over two years in the making) are also available. I certainly hope it will show more success than the launch of the similar U.S.-Russian venture and its subsequent complete failure."

4 of 66 comments (clear)

  1. They could pull it off. by blind+biker · · Score: 3, Interesting

    I have known Finland and Finns for almost 10 years - though I don't know the specifics of this project, I have a strong faith in the finnish high-tech (did you know atomic layer deposition was developed in Finland? And then there's Nokia, and a lot of nanotech research, and their contribution to the ESA and...) plus Finns are quite pedantic, and I mean this in the best possible way. Part of Nokia's success is definitely down to this scholarly approach to technological projects.

    --
    "The agriculture ministry is not in charge of Gundam" - Japanese ministry official.
  2. Making a better solar sail by Kim0 · · Score: 4, Interesting

    This should make the solar sail about 100 times lighter,
    and therefore faster:

    http://kim.oyhus.no/Solar_sail.html

    Kim Øyhus, the inventor.

  3. Re:Not quite the same thing really by Anonymous Coward · · Score: 3, Interesting

    Correction: As someone pointed out, the membrane type sails gather momentum from photons rather than ionized solar wind particles. The point still stands that the Finnish sail is a momentum-gathering device that requires no reaction mass. (Unlike a solar-electric ion drive or whatever the GP was thinking about)

    The low volume and speed of solar wind particles in comparison to sunlight does limit the performance. For example, you obviously can't go any faster than the solar wind, approx 500km/s near Earth. This is still a lot faster than previous deep space probes (the record is ~15km/s) so if they can get it to approach even 10% of the theoretical limit it'll be great for outer solar system studies.

  4. Re:Not quite the same thing really by Chrontius · · Score: 3, Interesting
    The solar system is in the middle of something called the "local bubble" - this region was created by an ancient supernova, and is defined by low-density interstellar medium. Also, the ram field generates drag - consider that this is going to look a lot like a giant parachute of magnetic force in front of the ship, that's not very aerodynamic. The drag and the thrust for a conventional Bussard fusion ramjet limit top speed to about 12-14% of lightspeed, which is just about as doable using a conventional fusion rocket design without the ram field. Also, the minimum operating speed of a ramjet is 1-6% of c.

    A proton-proton fusion drive has an exhaust velocity of 12% c, so a proton-proton fusion Bussard Ramjet would have a maximum speed of 12% c. You may remember that a spacecraft with a mass ratio that equals e (that is, 2.71828...) will have a total deltaV is exactly equal to the exhaust velocity. So if a conventional fusion rocket with a mass ratio of 3 or more has a better deltaV than a Bussard Ramjet, what's the point of using a ramjet?
    Some good reading for you over at Atomic Rocket Ship.