* Astronomy

A solar sail that scientists believe could power missions into deep space has passed its first major test.
A 20-metre square sail was deployed and its orientation controlled in a vacuum chamber designed to mimic space at NASA's Glenn Research Centre in Ohio, by developers ATK Space Systems who are Supplier of aerospace and defence products to US Government.
NASA has described the tests as a "crucial milestone" in the development of a unique propulsion technology that could be used to send probes to study the sun and the rest of the solar system.



Solar sail propulsion uses energy from the sun in the same way that a sailing boat is powered by the wind, reducing the need for a spacecraft to carry heavy fuel reserves.
A stream of solar energy particles bounce off giant reflective sails made of lightweight material 100 times thinner than a piece of writing paper, providing sufficient momentum to send a spacecraft speeding through space.
A spacecraft powered by a solar sail would require no onboard propellant, increasing its range of mobility and enabling it to hover at a fixed point in space for longer periods of time.
"A spacecraft utilizing solar sail propulsion can deploy a large, lightweight reflector -- up to tens of meters long, but very, very lightweight -- that can reflect sunlight. As it reflects the Sun's energy, the sail will move and carry a small payload or a spacecraft along with it. As long as there's sunlight, there can be propulsion." - Les Johnson of NASA's In-Space Propulsion Technology Office.
The first deployment of the solar sail, which weighs just 23 kilograms, had gone "flawlessly." The series of tests continue until July.
A solar sail spacecraft would need a wingspan of 80 to 160 metres to gain sufficient momentum from the sun, depending on the mass of the craft.
Since the spacecraft would continue to accelerate, reaching speeds of tens of thousands of miles an hour, it could theoretically reach the edge of the solar system faster than a conventionally fuelled craft.
NASA is not alone in recognizing the potential of solar sail propulsion.
Japan has already deployed two solar sails in space, while the Planetary Society, a non-profit U.S. group dedicated to promoting space exploration, hopes to launch its first solar sail from a Russian submarine in the next few weeks.

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