NASA is going to test a new solar sail system to determine if it's a viable alternative to propellant-based thrusters for maneuvering small satellites, and potentially for low-cost transportation of spacecraft set on deep-space missions. The agency has selected Illinois-based NanoAvionics to provide the spacecraft that will be used to test the solar sail system, the company announced today.
The mission, called NASA's Advanced Composite Solar Sail System or ACS3, is headed by NASA's Ames Research System, and will see a small satellite deployed to low Earth orbit equipped with a solar sail that unfurls to cover around 800 square feet – the size of a pretty large one bedroom apartment. The sail will work by actually propelling the spacecraft using not solar power, but the energy generated by photons from the sun striking the sail. This method results in very little force generated, but the accumulated power in a vacuum without the interference of friction means that eventually, a spacecraft using this method of propulsion can build up quite a head of steam.
NASA wants to develop this kind of propulsion system because they don't require any propellant at all, which greatly decreases the cost of launch and operation. They could undertake long-duration missions like traveling the solar system as scientific scouts, and eventually take on even more complicated tasks like deep-space asteroid mining, where conventional fuel systems make the costs and logistics unfeasible.
Solar sail technology is not new, and NASA has flown a test solar sail before, in 2011, though a second demonstration flight called Sunjammer was cancelled prior to a flight test in 2014. Non-profit scientific organization The Planetary Society flew its own crowd-funded solar sail spacecraft last year, and demonstrated that it was able to raise the orbit of a small satellite using only the power of the sun.