Blast off for solar-sail test craft

Sun blows

By Lucy Sherriff • Get more from this author

Posted in Science, 21st June 2005 14:22 GMT

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A privately-funded spacecraft powered by a solar sail is set for launch this evening. The Cosmos-1 mission will be launched into orbit from a Russian submarine in the Barents Sea, in the Arctic Ocean, this evening at 8:46pm, UK time.

The craft will power its way to a 500 mile-high orbit atop a modified Volna intercontinental ballistic missile (ICBM). The missile, which would not normally have enough power to reach orbit, has an additional rocket attached, similar to those used to de-orbit satellites. This should provide enough of an extra kick to get the craft to the necessary altitude.

Once in orbit, the experimental craft will wait four days before extending its solar sails, and will use this time to take pictures of Earth. Once unfurled, the sails will form a 30m circle that uses the momentum of solar photons to generate a very small, but constant, acceleration away from the sun. This acceleration is so small, in fact, that the craft will stay in orbit for several weeks, gradually gaining speed and altitude until it reaches escape velocity.

Solar sails have long been touted as the most realistic way of powering interstellar exploration, because although the acceleration is small, over a long enough time, a craft could achieve a very high velocity.

The $4m project has been funded by a TV station, and the Planetary Society in California. NASA is reportedly keen to get its hands on the experimental data from the expedition.

"Cosmos-1 is a short-term, modest mission that simply intends to prove the concept - that solar sailing is possible," The Planetary Society's Amir Alexander told the BBC.

"[It] is really the only known technology that could potentially take us to the stars one day, because it does not have to carry fuel with it and because it can keep accelerating - even at incredible distances," he added. ®