Hoist Up the LightSail-1: New Solar Sailing Project Underway

As if solar energy wasn’t already useful enough, it turns out solar radiation exerts a small amount of thrust on objects in its path. It won’t send your solar panels flying south for the winter, but it could one day revolutionize interstellar travel. The idea is solar sailing, and it’s not a new one. Attempts have been made over several decades to literally sail through outer space, but none as of yet have been especially successful. However, one organization, the Planetary Society, is not giving up – and for good reason, as the potential benefits of a successful solar sail are staggering.

What are Solar Sails?

Solar sails are made up of super thin metal, plastic or composite materials that, upon reflecting solar radiation, experience a tiny amount of thrust from each photon of light. This force is imperceptibly small on earth, but in the vacuum of space, its effect is cumulative and can provide enough thrust to propel a sail at speeds reaching a high fraction of the speed of light. Much like sailboats, solar sails are steerable. Adjustments to the sails change the way the solar radiation is reflected and thus the direction in which the craft moves.

Solar sailing is based in Einsteinian physics and was first proposed in the 1920s by a Russian space engineer. Since then, generations of scientists have been working to design, deploy and propel solar sails. To date, “solar sailors” have only been successful in design and deployment. Two recent attempts, one by NASA, were unsuccessful due to failures in the rockets attempting to carry sails into orbit. The second most recent attempt in 2005 was a joint venture between the Planetary Society and the Russian Academy of Sciences. It never reached orbit.

The First Flight of LightSail-1

But the Planetary Society is not giving up. The group has announced a new three-phase plan to deploy and test solar sails in and beyond earth’s orbit. LightSail-1 will be first. It’s a smaller test sail that will deploy roughly 500 miles above earth, just beyond the earth’s atmosphere and the inhibiting friction that it creates. The $2-million project will be a test of the steering capability of a solar sail.

LightSail-1 will hopefully be deployed by the end of 2010. If successful and future funding arrives, LightSails-2 and -3 will take off in the years to come. LightSail-1 will deploy just beyond the earth’s atmosphere but remain in orbit. LightSail-2 will go higher and remain longer. LightSail-3 will leave the earth’s orbit and position itself between the sun and earth about one million miles away.

What Can Be Gained From Solar Sailing?

There is a point between a planet and the sun at which the the gravitational pull of both objects cancel each other out. By positioning itself carefully at this point, a solar sail can actually hover above a planet for a long time with only minor corrections to its position. This could allow scientists to get a rare, lengthy glimpse at the sun and its interaction over time on a certain point on earth, namely over its magnetic poles.

In addition to speed and hover ability, a big advantage for solar sails is fuel savings. The more we use solar radiation to sail through space, the less conventional fuel is needed, resulting in longer, cheaper space flights with potential for sending probes well beyond our own galaxy on controlled flight paths.

Someday, much like Magellan, Columbus and Captain Cook, humankind will sail on to new horizons. Only this time, it won’t be new continents, but new galaxies to which we set our sails.

Sources: Christian Science Monitor, Wikipedia

Photo Credits: Spaceports & NASA

Posted on November 18th in Solar Research by Dan.