The LightSail 2 spacecraft will trip on sunshine no extra.
The Planetary Society’s crowdfunded solar crusing craft re-entered Earth’s atmosphere on Thursday morning (Nov.17) after practically 3.5 years in orbit — greater than thrice longer than its designed mission life.
The LightSail 2 staff has obtained no communications from the spacecraft since that date, main them to conclude that the shoebox-sized craft had lastly given up the ghost after finishing 18,000 orbits and touring about 5 million miles (8 million kilometers) round our planet.
“LightSail 2 is gone after more than three glorious years in the sky, blazing a trail of lift with light, and proving that we could defy gravity by tacking a sail in space,” science communicator Bill Nye, CEO of The Planetary Society, mentioned in a statement (opens in new tab). “The mission was funded by tens of thousands of Planetary Society members, who want to advance space technology.”
LightSail 2 was the primary small spacecraft to reveal managed solar crusing, harnessing photons from the sun to regulate its orbit. (LightSail 2 wasn’t the primary craft of any kind to solar sail in space, nevertheless; Japan’s Ikaros probe did so in 2010.)
While gentle lacks mass, its particular person particles — photons — carry momentum that may be transferred to a reflective floor to offer it a tiny quantity of push.
LightSail 2 has proven that solar crusing is an efficient and viable propulsion methodology for small spacecraft, together with tiny satellites generally known as cubesats, staff members mentioned.
LightSail Program Manager and Chief Scientist Bruce Betts wrote in a Planetary Society statement (opens in new tab) that deorbiting was at all times going to be LightSail 2’s destiny, although the fiery finish to the mission took longer to manifest than predicted.
The finish of LightSail 2 was a drag
LightSail 2 launched in June 2019 aboard a SpaceX Falcon Heavy rocket, tasked with a one-year mission to demonstrated managed solar crusing in orbit. It started its operations at an altitude of about 450 miles (720 kilometers) above Earth — barely greater than the orbit of the International Space Station (ISS).
At this altitude, Earth’s ambiance continues to be dense sufficient to exert a slight drag on a spacecraft, and it’s this impact that finally sealed the destiny of LightSail 2.
Because of the massive floor space of the craft’s solar sail, which measured 244 sq. ft (32 sq. meters) — in regards to the dimension of a boxing ring — it skilled a bigger drag impact than different spacecraft of its mass.
“Imagine throwing a rock compared to throwing a piece of paper. Atmospheric drag will stop the paper much faster than the rock. In our case, LightSail 2 is the paper,” Betts wrote. “A spacecraft like the ISS is huge but also massive, more like the rock. But even the ISS has to be boosted higher every few weeks using rockets to compensate for drag.”
During its third yr of operations, by which it demonstrated its best solar crusing, LightSail 2 skilled elevated atmospheric drag resulting from a lift in solar exercise. This exercise from the sun heated the ambiance, making the realm LightSail 2 handed by way of denser.
“That marked the beginning of the end,” Betts wrote. “As solar activity increased even more, solar sailing was unable to compete with the increased drag due to atmospheric density increase.”
Over the final a number of weeks, LightSail 2 had been dropping deeper and deeper into Earth’s ambiance, experiencing increasingly drag, which, in flip, dramatically elevated the speed of its drop.
“The spacecraft was caught in an ever-increasing snowball effect: as the spacecraft got lower, the density increased, which caused the spacecraft to get lower even more quickly,” Betts wrote.
While LightSail 2’s mission could also be over, there’s nonetheless scientific work to be performed. The staff behind the mission is continuous to research knowledge collected by the craft, which remained operational till its ultimate moments.
This knowledge may even be shared with future space missions that additionally make use of solar sails, equivalent to NASA’s NEA Scout, which launched on the company’s Artemis 1 mission on Nov. 16 and can hitch a trip on daylight to journey to the moon after which on to a near-Earth asteroid.
“Despite the sadness at seeing it go, all those who worked on this project and the 50,000 individual donors who completely funded the LightSail program should reflect on this as a moment of pride,” Betts wrote.