Intention to launch a spacecraft that will run on solar energy
Andrew Bridges
Launching the solar sail into space. chart
Pasadena, Calif. (AP). Forget bulky missiles and expensive fuel. An American-Russian partnership plans to launch a spacecraft that will float in space on pressure exerted by the sun's rays. The group hopes that the solar sails can be used to direct the trajectories of spacecraft, move between planets, and perhaps even transport humans to other planets in the future.
The people behind the project hope that a suborbital test flight scheduled for spring will prove that the tightly packed solar sail can unfold in space, like a giant kite. A more ambitious operation will take place in October, when the team will send a larger version of the sail, for what is supposed to be a flight around the Earth.
"We will feel that we have succeeded even if we fly for a short time," said Louis Friedman, the director of the project "Cosmos."1
The sail uses solar pressure in the same way that a sailboat uses wind. It is made of a large sheet of reflective material, and a skeleton made of inflatable beams that maintain its taut shape. The advantage of the sail is similar to that of a sailboat - there is no need to carry a lot of fuel, and air currents help its movement. When the sun's energy hits the surface of the solar sail, the particles (photons), moving at the speed of light, provide a constant boost that can be increased or decreased depending on the relationship of the sail to the sun.
In both cases, an intercontinental ballistic missile will launch the sail from a Russian nuclear submarine in the Barents Sea - a relatively inexpensive option, which helped keep the project budget below four million dollars. The project is funded by "Cosmos Studios" - a communications company specializing in scientific projects. The spacecraft is built by the "Babkin" space center in Russia, while the launch vehicle is built by the "Makiv" rocket design company. The Space Research Institute of the Russian Academy of Sciences serves as one of the project's subcontractors.
The advantages of the solar sail can be enormous. According to Cosmos Studios, the sails can, theoretically, reach ten times the speed of NASA's Voyager 1 and 2 spacecraft, which reach a speed of 61,142 km/h. The American and European space agencies, and at least one private company, hope that in the future they will be able to rely on the new technology, since it is sophisticated but relatively cheap.
Last year, NASA stated that by 2010, an interstellar research satellite would be sent using spacecraft. The sail, which is 400 meters wide, will be the largest spacecraft ever built. The solar-powered spacecraft will increase its speed slowly but after a while it will be able to reach speeds that will allow travel over great distances.
The launch to be held in April will test the retirement of two petal-like propellers. At the end of the short flight, the sail, which is about a fifth as thick as a trash bag, will fall back to Earth.
In the orbital flight that will take place later this year, a larger eight-petaled sail will be launched. Inflatable support beams will pull the sail out of a tank and stiffen to support it. Each of the triple petals is able to rotate to steer the spacecraft, allowing it to change direction like a sailing ship.
{Appeared in Haaretz newspaper, 28/2/2001{
