Software problem "pauses" LightSail mission
The Planetary Society says that its LightSail solar sail mission has been "paused" due to a software glitch, which has frozen the onboard computer in a fashion all too familiar to terrestrial technology users. Launched on May 20, the satellite, which is about the size of a loaf of bread, ceased transmitting at 5:31 EDT (21:31 GMT) on May 22 due to what engineers believe is a design flaw in the avionics software.
The LightSail CubeSat reportedly operated as planned after its launch atop an Atlas V rocket from Cape Canaveral Air Force Station as a piggyback payload along with the US Air Force's X-37B unmanned spaceplane. As it passed over ground stations operated by Cal Poly San Luis Obispo and Georgia Tech, its power and temperature levels indicated nominal operations as data packets were transmitted back to Earth every 15 seconds.
The Society says that the problem was that every time LightSail transmitted a packet, it stored a copy in a datafile file called beacon.csv. This continued until the file reached 32 megabytes and crashed the system. This was a shortcoming that was already known to the manufacturer of the avionics board and the Society had planned to transmit a fix, but the computer froze before this could be carried out.
The flight team compares the problem to that of an ordinary Earthside computer that fails to respond and needs to be restarted. As anyone who has used a computer for any length of time knows, simply giving the machine an order to reboot won't work if the computer isn't responding, which means manually turning it off and on. This appears to be the case with the LightSail, which has failed to respond to restart commands. The LightSail has a power switch installed, but that isn't of much use.
"There’s nobody in outer space to push that reset button," says Planetary CEO Bill Nye.
The team is now hoping that either the satellite will respond to repeated commands that are being sent automatically, or the electronics will be struck by cosmic rays – an event that often causes satellites to reboot themselves.
The LightSail was built by the nonprofit Planetary Society as a technology demonstrator for a non-rocket propulsion system that uses a Mylar sail to turn the light of the Sun into thrust in a similar way to a sail boat catching the wind. The Society says that if it does manage to reboot the spacecraft, it will be ordered to deploy its solar sails as soon as possible to begin the test program and move it to a higher orbit. Failing this, the satellite will be able to continue in orbit for another six months.
Source: The Planetary Society
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This is good learning - recovery/backup systems need to be more robust than this, which this expensive slap-in-the-face has taught them now.