LightSail loses contact with Earth

Chuck Bednar for redOrbit.com – @BednarChuck

A computer problem during the test flight of the Planetary Society’s LightSail spacecraft has left the prototype satellite unable to communicate with mission control, preventing (at least for now) the scheduled deployment of its solar sails to ensure that they work as planned.

What went wrong? According to Engadget and Popular Science, LightSail’s hardware launched with an older version of its Linux-based operating system, and as it turns out, this version of the OS shipped with a major glitch. It was to transmit a series of data packets back to Earth, sending detailed information about its position and other relevant data.

After the first two days, however, the transmissions went silent. The Planetary Society believes that with each packet it sent, it created a file too big for the software to handle, causing the OS to crash. Specifically, once its file reached 32 megabytes in size, the flight system locked up. While the issue was fixed in later versions of the OS, it persists on LightSail’s system.

Fixing the likely frozen LightSail

For the time being, the Planetary Society has put the spacecraft’s primary mission on hold so that they can deal with the software issue. They believe that the system is frozen, and while the flight control team has been attempting to send commands to LightSail in order to get it to reboot, thus far their attempts have been to no avail.

“The team is looking into other possible ways to reboot the system, but there’s also the chance that charged particles in space may strike an electrical component of the system and zap it awake (no, seriously),” Popular Science said. “If that happens, the Planetary Society won’t waste any time and will deploy the solar sail immediately, lest the software freeze again.”

In a blog entry posted earlier this week, the Planetary Society said that personnel at both the Cal Poly San Luis Obispo and Georgia Tech ground stations would continue to be on the lookout for the probe as it passed by. The Cal Poly team would be automating the reboot command so that it would be sent to Light Sail on every few ground station passes, with the hope that one of the commands would find its way to the spacecraft and fix the issue.

Mission control personnel are also reportedly evaluating a series of fixes that could allow them to work around software vulnerability, if and when contact is reestablished. One, they explained, is a Linux file redirect that would send the contents of the problematic file to a null location – “a sort-of software black hole,” they explained. Early tests using this technique have been called “promising,” the organization said.

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