Solar sail mission might help clean up low-Earth orbit

NASA announced on November 29, 2011 that its Nanosail-D solar sail mission is complete. It’s possible this tiny satellite and its beautiful solar sail will herald a new era in cleaning up space junk in low-Earth orbit.

Nanosail-D is just cool, for many reasons. It’s the satellite that carried NASA’s first-ever solar sail in low-Earth orbit. After some nail-biting weeks in late 2010 and early 2011, when NanoSail-D remained stuck inside its mothership (the Fast, Affordable, Science and Technology SATellite, or FASTSAT), the satellite successfully left its mothership on January 17, 2011. Its solar sail unfurled a few days later, on January 20. It went on to spend 240 days sailing around Earth. Then it burned up after re-entering Earth’s atmosphere on September 17, 2011.

The re-entry was precisely the point. The mission successfully demonstrated a way of using solar sails to bring down decommissioned satellites and space debris, letting them re-enter and totally burn up in the Earth’s atmosphere. Nanosail-D’s science team continues to analyze the orbital data to determine how future satellites can use this new technology. If you’ll remember some more recent nail-biting moments – caused by the uncontrolled reentry NASA’s UARS satellite on September 24, 2011 – you’ll definitely see why Nanosail-D served a purpose.

While the scientists crunch the data, you can enjoy the slideshow below, made possible by a collaboration between NASA and Spacweather.com

NASA formed a partnership with Spaceweather.com to engage the amateur astronomy community to submit images of the orbiting NanoSail-D solar sail during the flight phase of the mission. NanoSail-D was a very elusive target to spot in the night sky – at times very bright and other times difficult to see at all. Many ground observations were made over the course of the mission. The imaging challenge concluded with NanoSail-D’s deorbit. Winners of the photo contest will be announced in early 2012.

By the way, initial assessment indicates NanoSail-D exhibited the predicted cyclical deorbit rate behavior that was only previously theorized by researchers. Dean Alhorn, principal investigator for NanoSail-D at Marshall Space Flight Center, said:

The final rate of descent depended on the nature of solar activity, the density of the atmosphere surrounding NanoSail-D and the angle of the sail to the orbital track. It is astounding to see how the satellite reacted to the sun’s solar pressure. The recent solar flares increased the drag and brought the nanosatellite back home quickly.

Bottom line: NASA called an official end to its Nanosail-D mission today (November 29, 2011). The satellite reentered Earth’s atmosphere on September 17, 2011, after carrying NASA’s first-ever solar sail in low-Earth orbit for 240 days. The reentry of the satellite is also important and might pave the way for safe reentry into Earth’s atmosphere of decommissioned satellites and space debris.

From early 2011: Flash of light brighter than Venus? Could be first solar sail to orbit Earth