The Planetary Society’s LightSail 2 spacecraft has reentered Earth’s atmosphere, successfully completing its mission to demonstrate flight by light for small spacecraft. LightSail 2 reentered sometime on Nov. 17, according to orbital predictions.
The reentry completes a mission of nearly three-and-a-half years, during which LightSail 2 showed that it could change its orbit using the gentle push of sunlight, a technique known as solar sailing. LightSail 2 demonstrated that small spacecraft can carry, deploy, and utilize relatively large solar sails for propulsion.
“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,” said Bill Nye, CEO of The Planetary Society. “The mission was funded by tens of thousands of Planetary Society members and backers, who want to advance space technology. And, take a look at these pictures! With this small spacecraft, we provided citizens of Earth with awe-inspiring overviews of our home world.”
LightSail 2 hitched a ride to space in June 2019 aboard a SpaceX Falcon Heavy rocket. It began operations at an altitude of about 720 kilometers (450 miles), where Earth’s atmosphere is still thick enough to create drag and slow down a spacecraft. For reference, the International Space Station orbits at an altitude of roughly 400 kilometers (250 miles).
As atmospheric drag slowly pulled LightSail 2 back towards Earth, the spacecraft successfully used solar sailing to lower its decay rate and on occasion overcome drag completely. After 18,000 orbits and 8 million kilometers (5 million miles) traveled, drag finally won out, bringing the mission to a close.
“During its extended mission LightSail 2 continued to teach us more about solar sailing and achieved its most effective solar sailing, but that was followed by an increase in atmospheric drag in part from increasing solar activity,” said Bruce Betts, LightSail program manager and chief scientist for The Planetary Society. “The spacecraft is gone, but data analyses and sharing of results will continue.”
Greetings, LightSail fans!
In our last report, we talked about our scale-model LightSail ending its run at the Smithsonian's FUTURES Exhibit. Our CEO Bill Nye and members of our Development staff and volunteers flew to Washington, D.C. toward the end of June - our first Planetary Society travel since before the pandemic!
Planetary Society members in the area were invited to see LightSail at the FUTURES Exhibit before its closing. Members heard remarks from our CEO and from our Chief Development Officer, Richard Chute about LightSail's mission. Afterward, we traipsed down to the National Mall for Hofstra University's "Astronomy on the Mall", a public outreach event that was part of the Smithsonian's Solstice Saturday celebration. Bill obligingly took selfies with our members and we had hundreds of visitors to our table, where we shared information about The Planetary Society and our LightSail mission.
As for LightSail itself, the Smithsonian has sent it safely back to our headquarters in Pasadena, California. Our actual solar sail is still out there, providing the Mission team with important data and - just as importantly - the breathtaking photos we have been sharing since its launch in 2019. The atmosphere is expanding due to recent solar activity, which is increasing the atmospheric drag on LightSail. We don't how much longer it will stay up there, but you can be certain that we will be planning activities to mark the end of the mission that Popular Science gave the Grand Award for the most impressive aerospace innovation of 2019!
Thanks to all of you for your support of LightSail!
Our scale model of LightSail, that is...
Since November of 2021, our LightSail model has been in Washington, D.C. as part of the FUTURES exhibit at the Smithsonian Institution's Art + Industries Building. FUTURES is an incredible collection of art and technology representing the future of humanity, and it's been a great honor for The Planetary Society to be a part of it. Our CEO Bill Nye was at the opening of the exhibit, as seen in the photo above.
Before the FUTURES exhibit closes later this month, Bill and Planetary Society staff members are traveling to Washington, D.C. for the Smithsonian Solstice Saturday. Several of the museums there will be open until midnight, and the Astronomy Festival on the National Mall will run from 6:00 to 11:00 pm.
It's going to be a wonderful event, and if you're in the D.C. area, do try to see LightSail before the exhibit ends. If you find yourself at the Astronomy Festival on the National Mall, be sure to stop by The Planetary Society's table on the Mall and say hello. Planetary Society members wearing their membership tee or pin, or carrying their membership card, will get swag!
Your support and enthusiasm for solar sailing are making a mark on the future of space exploration. Thank you for your support of LightSail.
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Nearly two-and-a-half years after launching into Earth orbit, The Planetary Society's LightSail 2 solar sail mission is still going strong.
The spacecraft is currently operating in an extended mission to further advance solar sailing technology. The LightSail 2 team is gathering vital data about the performance of the solar sail and using imagery to track its condition over time.
Ten new processed pictures from space have been added to the mission's image library, which you can access here.
The Planetary Society shares mission data with NASA to assist three upcoming solar sail missions: NEA Scout, Solar Cruiser and ACS3. NEA Scout is scheduled to hitch a ride to lunar space as early as this month on NASA's Space Launch System rocker during the Artemis 1 test flight.
At LightSail's altitude above Earth - currently about 687 kilometers - there is still enough atmosphere to counteract the thrust gained from solar sailing and slowly pull it back to Earth. The spacecraft will eventually succumb to drag and reenter Earth's atmosphere.
There are signs that the spacecraft's solar sail may be starting to degrade, although the extent is under study. The mission team will continue to track and analyze the sail's condition, as the data could prove valuable to other solar missions.LightSail 2 monitors its sails condition using two fish-eye cameras mounted at the end of two solar panels.
Almost 30 months after liftoff, the mission continues to impress. For now, LightSail 2 will continue to teach the world about solar sailing, returning inspiring images and helping prepare for the next generation of solar sail mission.
Since launching LightSail 2 in 2019, all of us at The Planetary Society, along with our donors and members, continue to be surprised and enchanted by all things LightSail. Whether it's the stunning photographs of our world taken by LightSail's cameras or the contributions LightSail is making towards the future of solar sailing, LightSail's "flight by light" continues to inspire!
LightSail is now officially in an "extended mission" phase. We recently celebrated by holding an online auction for one-of-a-kind LightSail swag to help raise funds to keep the mission going and also premiered "Sailing The Light", a 35-minute documentary about the game-changing LightSail 2 mission.
We plan to operate LightSail 2 as long as possible in order to learn more about solar sailing and solar sail spacecraft operations. We also want to continue raising the profile of solar sailing by sharing the excitement of the mission with the public, while documenting our results to ensure the strongest possible legacy for the LightSail program.
NASA's Advanced Composite Solar Sail System, or ACS3, is slated to launch in 2022 and will build on the groundwork we have established with LightSail 2. Carl Sagan's long-held dream of sailing the solar winds has come true, and you have helped make this citizen-funded project a reality. Thank you for your support!
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