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Privately funded solar sail test flight runs into trouble

Irene Klotz, Spaceflight Correspondent
May 27, 2015, 21:43 UTC

Sen—A software glitch is threatening to end the test run of an innovative, privately funded space experiment intended to lay the foundation for an operational solar-sailing spacecraft.

The privately funded Planetary Society, a California-based space exploration advocacy group, has not been in communication with its LightSail since Friday, two days after it hitched a ride to orbit aboard an Atlas 5 rocket carrying the U.S. Air Force’s X-37B robotic mini shuttle.

LightSail, a CubeSat that is about the size of a loaf of bread, had been sending automated signals back to Earth every 15 seconds as teams prepared to test a prototype sail deployment mechanism next month.

But the electronic chirping came to an abrupt halt on Friday. Troubleshooting efforts over the long Memorial Day holiday weekend were not successful, the Planetary Society said in a blog post on its website.

“It is now believed that a vulnerability in the software controlling the main avionics board halted spacecraft operations, leaving a reboot as the only remedy to continue the mission. When that occurs, the team will likely initiate a manual sail deployment as soon as possible,” wrote the Planetary Society’s digital editor Jason Davis.

Since software uploads have failed, rebooting the computer may now require a helping hand from Mother Nature.

“Spacecraft are susceptible to charged particles zipping through deep space, many of which get trapped inside Earth’s magnetic field. If one of these particles strikes an electronics component in just the right way, it can cause a reboot,” Davis said.

“This is not an uncommon occurrence,” he said, adding that most CubeSats experience a reboot in the first three weeks. If successful, that would put LightSail close its baseline timeline of sail deployment 28 days after launch.

Tucked inside the CubeSat, LightSail should be able to remain in orbit for about six months.

Solar sailing is an experimental in-space propulsion system that uses the pressure of photons from the Sun to generate a gentle but increasing push on a thin film, similar to how a sailboat moves by the force of wind.

The Planetary Society has long been interested in the technology and raised funds for an orbital test run to assess how a 32-square meter sail would deploy. The organization plans a full-fledged demonstration of solar sailing in 2016.