2004
First Solar Sail
The Planetary Society and sponsor Cosmos Studios are launching a SOLAR SAIL!
Cosmos 1 will be the first solar sail EVER! It’s the first time a NONPROFIT ORGANIZATION is paying for a spacecraft.
Cosmos 1 is a 30 meter diameter sail, configured in 8 triangular blades. The sails are made of 5-micron-thin aluminized reinforced Mylar, so the entire spacecraft only weighs 40 kilograms. It will be launched by Volna, a submarine launched converted ICBM. That’s right, an InterContinental Ballistic Missile launched from a SUBMARINE will propel Cosmos 1 into a 850 kilometer near polar orbit!
The submarine launch will be from the Barents Sea north of Murmansk.
A test of the solar sail deployment was conducted in a Volna-launched, suborbital flight in July 2001.
How does a solar sail work? The solar sail will use the pressure of sunlight to increase its orbital energy and raise its orbital altitude. The sail is controlled by pitching the blades, thus turning the direction of the solar force. The inflatable tubes keep the sail rigid.
The great advantage of a solar sail is that it REQUIRES NO FUEL. Standard chemical rockets give spacecrafts a quick boost into Earth orbit. The spacecraft then coasts most of the way to its destination, with some small blasts from thrusters to adjust its trajectory. This requires a lot of fuel. Solar sails give a very low thrust, but they can work continuously, pushing spacecraft faster and faster. A solar sail spacecraft can, in time, move the spacecraft even faster than a chemical rocket.
When the light from the Sun hits the surface of the solar sail the energy, or momentum, of photons (light particles) is transferred to the sail – as the light is reflected away, it gives the sail a slight “push.” The force is controlled by the angle of the sail with respect to the Sun, adding to or subtracting from the orbital velocity.
WHY a solar sail? To demonstrate the technique for traveling between planets — and someday, to the stars!
To the stars? Sure, once you get much beyond the orbit of Jupiter, energy from sunlight is too weak. But lasers can be directed at the sails. Lasers stay in a tight beam so that most of their energy can be imparted to the sail, and not diffuses into space. Very large lasers could be used to help us travel to other stars. In the future, people may travel to distant stars using laser powered solar sails.
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