The Planetary Society's brief yet successful LightSail mission came to a fiery end on Sunday. The non-profit Society announced today that after 25 days in orbit, the CubeSat designed to test a solar sail propulsion system burned up after reentering the Earth’s atmosphere somewhere over the South Atlantic.
About the size of a loaf of bread, LightSail was launched on May 20 from Cape Canaveral Air Force Station in Florida as a piggyback cargo atop an Atlas V rocket for the US Air Force's AFSPC-5 mission. Its purpose was to test critical systems for a solar sail system that uses the pressure of sunlight to propel a spacecraft, similar to the way wind propels a sailing ship.
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From the start, the mission suffered from difficulties. After entering low-Earth orbit, the spacecraft lost contact with mission control twice and had problems with its battery system. At one point, its computer froze and only rebooted because the electronics were struck by cosmic rays.
Despite these setbacks, the satellite was able to successfully deploy its Mylar sail and send back telemetry and image confirmation, fulfilling the main mission objective. Unfortunately, the Society says that soon after this, LightSail started sending a "continuous, nonsensical signal" and failed to respond to commands.
Final radio contact was on June 10 at 11:29 pm EDT, when telemetry indicated that the spacecraft was in a very slow tumble that accelerated as LightSail sank deeper into the atmosphere, spinning once every 21 seconds on the day before reentry.
The Society says that the LightSail signal was last heard by Justin Foley of Cal Poly on June 14 at 12:52 pm EDT. Based on orbital models, the Society estimates that it burned up at about 1:23 pm EDT (17:23 GMT) that day. However, there is a report from Germany that the spacecraft’s signal was still transmitting hours later, raising speculation that it might be from the avionics and radio systems breaking away from the main craft and continuing to transmit for a few more orbits before a final burn up.
A second mission is set for 2016. It will be launched to an altitude of 450 mi (720 km) as part of the payload of Georgia Tech's Prox-1 mission, where it will act as a rendezvous target for the Georgia Tech craft for two weeks before carrying out a full demonstration of the light-sail system by using the sail for actual propulsion.
Source: The Planetary Society