May 27, 2013
Space Exploration Technologies (SpaceX) is slated to fly NASA's $27 million Sunjammer solar-sail demonstration next year as a secondary payload with the National Oceanic and Atmospheric Organization's (NOAA) revived Deep Space Climate Observatory (Dscovr) satellite.
Named after Arthur C. Clarke's 1964 short story, Sunjammer aims to be the largest solar sail ever constructed and deployed in space, and could prove the feasibility of an advanced space warning system for more timely and accurate predictions of solar-flare activity.
Led by L'Garde Inc. of Tustin, Calif., with ground-station support provided by NOAA, Sunjammer's propellantless solar sail could demonstrate the potential for other practical applications as well, including space-debris removal and de-orbiting of spent satellites.
NASA says the mission builds on two successful ground-deployment experiments L'Garde conducted in 2005-06, quadrupling the area of the largest sail ever deployed on the ground, a 20 x 20-meter (4,300-sq.-ft.) behemoth tested by L'Garde at NASA's Plumbrook facility in Ohio. It also leverages the successful deployment of the NanoSail-D sail, a 100-sq.-ft. test article NASA launched in early 2011 to validate sail-deployment techniques.
“We're making a very high-performance sail and flying it in interplanetary space 300 million kilometers [186 million miles]—10 light seconds—from Earth,” says L'Garde Chief Operating Officer Nathan Barnes. “It's a point where we'll be far enough from the influence of the Earth's atmosphere that we'll get to do some really sporty things with the sail.”
Barnes says ultra-thin solar sails hold the potential to mitigate the Sun's force on spacecraft positioned at “pseudo” Lagrangian points close to the giant star—closer to the Sun than NOAA's Advanced Composition Explorer (ACE), which is currently monitoring coronal mass—where solar-weather satellites could provide more timely forecasts. NASA says the capability could improve space-weather warning time by up to 45 min.
Made of 5-micron-thick Kapton—the same material used to construct the giant sunshade on NASA's James Webb Space Telescope—the Sunjammer solar sail measures 1,200 sq. meters when fully deployed. When collapsed, however, it is the size of a dishwasher, weighs 70 lb. and is easily packed into a secondary payload on Falcon 9.