The Planetary Society announced plans on Monday to test a new means of space travel using beams of sunlight. The aptly-named "LightSail" spacecraft would be launched for a test flight aboard an Atlas V rocket in May -- paving the way for a full-fledged flight in 2016 -- according to a statement released by the U.S.-based space advocacy and exploration group.
The proposed propulsion system, which uses large, reflective surfaces called solar sails, aims to utilize the energy stored in photons -- elementary particles that transmit light -- to set sail on sunlight. Although photons do not have any mass, the momentum transferred when a photon collides with the solar sail could, in theory, propel the spacecraft forward, providing a continuous, albeit small, acceleration.
“The idea ultimately is to be able to tack like a sailboat on each orbit,” Executive Director of the society William Sanford Nye -- popularly known as “Bill Nye the Science Guy” -- told The New York Times, adding that both LightSails were built for less than $4 million.
In order to harness the energy stored in photons, the LightSail, which, during the launch, will be about the size of a loaf of bread -- 4 inches by 4 inches by 1 foot -- will unfurl four triangular pieces of Mylar, less than 1/5,000th of an inch thick, after it has spent a month in orbit, according to the statement. These solar sails will form a square reflective surface spanning nearly 345 square feet.
“We strongly believe this could be a big part of the future of interplanetary missions … it will ultimately eventually take a lot of missions a long, long way,” Nye told the Times.