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NASA solar sail lost in space

BY STEPHEN CLARK

SPACEFLIGHT NOW

Posted: December 11, 2010



NASA has not heard from the experimental NanoSail-D miniature solar sail in nearly a week, prompting officials to wonder if the craft actually deployed from a larger mother satellite despite initial indications it ejected as designed.

Artist's concept of NanoSail-D. Credit: NASA



The agency announced Monday the NanoSail-D ejected from the its mothership, the Fast, Affordable, Science and Technology Satellite, or FASTSAT. The deployment was supposed to trigger a three-day timer before issuing an automatic command to unfurl a 100 square foot ultra-thin polymer sail from NanoSail-D, which is about the size of a loaf of bread. NanoSail-D's spring-ejection was indicated at 1:31 a.m. EST Monday, leading to a predicted release of the spacecraft's sail membrane around 1:30 a.m. EST Thursday. But officials fear something went wrong with NanoSail-D. Engineers have been unable to contact the spacecraft since its suspected release early Monday, according to Kim Newton, a spokesperson at NASA's Marshall Space Flight Center in Huntsville, Ala. NASA posted an update on the mission website late Friday saying "it is not clear" that the small spacecraft was deployed from FASTSAT. "At the time of ejection, spacecraft telemetry data showed a positive ejection as reflected by confirmation of several of the planned on orbit ejection sequence events," the statement said. "The FASTSAT spacecraft ejection system data was also indicative of an ejection event." NanoSail-D was mounted in a P-POD ejection apparatus inside FASTSAT. P-PODs are typically positioned to release CubeSat spacecraft from launch vehicles, but NanoSail-D was expected to become the first CubeSat to separate from a microsatellite. Containing the small solar sail experiment and five other technology investigations, the 300-pound FASTSAT spacecraft launched Nov. 19 on a Minotaur 4 rocket from the Kodiak Launch Complex in Alaska. NASA still has not confirmed the sail deployment event, which was programmed to occur this week. Four spring-loaded guide booms were expected to pop out of the compact spacecraft, then the polymer membrane was designed to stretch tight in a diamond shape within about five seconds. "The FASTSAT team is continuing to troubleshoot the inability to make contact with NanoSail-D," NASA's statement said. "The FASTSAT microsatellite and all remaining five onboard experiments continue to operate as planned."

Artist's concept of FASTSAT. Credit: NASA



NanoSail-D's primary objectives were to eject the 8.5-pound satellite from FASTSAT and deploy the solar sail. NASA launched an identical NanoSail-D spacecraft in 2008, but the satellite was destroyed in a rocket mishap. Engineers spent the last two years preparing a backup spacecraft for blastoff. Both NanoSail-D vehicles were assembled on a budget of $500,000, according to Dean Alhorn, the NanoSail-D project manager at Marshall. The craft's solar sail is designed to harness light pressure from the sun to change its orbit, eventually slowing the craft's speed enough to drop from orbit and burn up in Earth's atmosphere. Solar sails don't generate much thrust, but they can propel lightweight spacecraft long distances into the solar system on timescales of months and years. A Japanese solar sail mission, named Ikaros, successfully demonstrated solar sailing on the way from Earth to Venus this summer. NanoSail-D's potential applications are closer to home. NASA and the U.S. military are interested in inexpensive methods of removing retired satellites from clogged traffic lanes in orbit. The military tracks nearly 16,000 objects larger than 4 inches circling Earth, and even small debris moving at high speeds pose serious threats to active spacecraft. DARPA, the Pentagon's research and development agency, is studying concepts to pull debris and old satellites out of operational orbits. Such a job is technically challenging, but legal and political hurdles loom even taller, according to experts. Low-cost CubeSat spacecraft like NanoSail-D could prove solar sails can be packed inside canisters like parachutes, providing a disposal system when satellites are finished with their missions. Over time, sails could slow satellite velocities enough to move the craft to graveyard orbits or into the atmosphere for a destructive reentry. NanoSail-D was designed to stay in orbit between 70 and 120 days, depending on atmospheric conditions.





