LightSail Finally Deploys Solar Sail

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WASHINGTON — After overcoming a battery problem that kept the spacecraft silent for several days, the Planetary Society’s LightSail spacecraft unfurled its solar sail June 7, the organization reported.

Controllers reading the spacecraft’s telemetry said that the deployment was going smoothly. Data showed the sail deployment motors had reached the halfway point as the spacecraft passed out of range of a ground station with no signs of problems.

“All indications are that the solar sail deployment was proceeding nominally,” LightSail’s Mission Manager David Spencer wrote in a June 7 update.

For such a nerve-wracking mission, filled with software glitches, computer crashes, and malfunctioning batteries, news of a nominal sail deployment came with great relief and great joy.

“We’ve learned a lot about perseverance on this test mission,” the Planetary Society’s Chief Executive, Bill Nye, said in a press release. “Although it’s in inertial space, LightSail has had me on a rollercoaster.”

The successful solar sail deployment marks an important milestone for the Pasadena, California-based Planetary Society, which has had a long-term interest in solar sail propulsion. Carl Sagan, a co-founder of the Planetary Society, was a big proponent of the idea.

LightSail’s journey began on May 20 aboard an Atlas 5 rocket that was also carrying the Air Force’s X-37B spaceplane. After two days in orbit, LightSail went silent when a software glitch crashed the onboard computers. On May 31, ground stations reestablished contact with LightSail after a cosmic ray hit the spacecraft’s circuit boards and initiated a reboot.

The team proceeded with the mission and commanded the craft to pop open its hinged side panels, making room for the solar sail to deploy. But problems with the spacecraft’s battery led to another shutdown on June 4.

Controllers restored contact with LightSail for the second time on Saturday. The analysis into the battery glitch was ongoing, but engineers suspected the spacecraft was stuck in a loop where the spacecraft was generating either too little or too much power, preventing the spacecraft’s batteries from charging.

Now, with its sail deployed, it is only a matter of days before atmospheric drag pushes LightSail from low Earth orbit into this chaotic test mission’s fiery finale. The Planetary Society’s next spacecraft, planned for a 2016 launch, will be placed in a higher orbit, allowing the craft to make full use its solar sail for propulsion unencumbered by drag.

When the LightSail project began in 2009, San Luis Obispo, California-based Stellar Exploration, Inc. was in charge of building the craft. But in 2014 Ecliptic Enterprises Corp. took over the integration and testing of LightSail, working out of Cal Poly San Luis Obispo. Borealis Space also worked on LightSail as a subcontractor to Ecliptic.