June 19, 2005. Copyright 2005. Graphic News. All rights reserved.

Solar sail to revolutionise space travel

LONDON, June 19, Graphic News: The first launch of a solar sail spacecraft will be made from a Russian atomic submarine in the Barents Sea on Tuesday (June 21).

The private U.S.-Russian consortium sponsoring the flight of Cosmos 1 say the large, lightweight reflective sheet will revolutionize space propulsion by using the gentle push of sunlight rather than costly fuel.

ÒItÕs the only known technology that can lead us to interstellar flight, to the stars,Ó said Louis Friedman, the president of the Planetary Society, which has funded the US$4 million experiment. The Planetary Society, which was co-founded by astronomer Carl Sagan, Bruce Murray and Friedman in 1980 to promote space exploration, is working with the Lavochkin Association, one of RussiaÕs largest aerospace companies, and the Space Research Institute in Russia.

When the Cosmos 1 blasts off on a converted Soviet-era intercontinental ballistic missile, it will carry into Earth orbit a CD containing the names of over 75,000 members of The Planetary Society and the Japan Planetary Society, along with the works of early visionaries -- such as the 1920Õs Russian rocket pioneer Fridrikh Tsander -- who inspired solar sailing.

Scientists describe light as little packets of energy called photons. It is the energy from these photons of light -- that can run a solar-powered calculator or watch -- which will propel the spacecraft, explained Friedman.

Once in Earth orbit Cosmos 1 will unfurl eight triangular panels to form a 100-feet wide (30-metre-wide) solar sail. Each panel is a very thin sheet of reflective Mylar. This ultra-thin plastic sheet -- about a quarter of the thickness of a trash bag -- will harness the miniscule force exerted by photons in a beam of sunlight in the same way that a sailboat is pushed along the water by the force of the wind.

The great advantage of solar sails over conventional propulsion systems is that they do not require huge loads of rocket fuel. In fact, NASA is studying the use of solar sails to propel the Interstellar Probe, a mission tentatively scheduled for launch in 2010. 

Although a solar sail is at first slower than a conventional rocket, it continues to accelerate over time. Designers say a spacecraft with solar sails could accelerate to speeds as high as 55 miles per second (90 kilometers per second), allowing it to travel far beyond the solar system in just a few years. 

ÒCosmos 1 could serve as a stepping-stone for such efforts,Ó says Friedman, who compares it to the first flight of an aircraft by the Wright brothers in 1903. ÒI hope this will be the beginning of something grand.Ó

/ENDS

Source: Planetary Society