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upstart writes:

LightSail 2 has been flying for 30 months now, paving the way for future solar sail missions:

Even after 30 months in space, The Planetary Society's LightSail 2 mission continues to successfully "sail on sunbeams," demonstrating solar sail technology in Earth orbit. The mission is providing hard data for future missions that hope to employ solar sails to explore the cosmos.

LightSail 2, a small cubesat, launched in June 2019 on a SpaceX Falcon Heavy, as a demonstration mission to test how well a solar sail could change the orbit of a spacecraft. A month after launch, when LightSail 2 unfurled its ultra-thin 32-square-meter Mylar sail, the mission was declared a success because the sail raised the orbit of the small, loaf-of-bread-sized spacecraft.

"We're going to a higher orbital altitude without rocket fuel, just with the push of sunlight," The Planetary Society's (TPS) CEO Bill Nye said at a press conference following the deployment. "This idea that you could fly a spacecraft and could get propulsion in space form nothing but photons, it's surprising, and for me, it's very romantic that you'd be sailing on sunbeams."

LightSail 2 Has Been Flying in Space for 30 Months – Paving the Way for Future Solar Sail Missions:

[...] Solar sails use the power of photons from the Sun to propel spacecraft. While photons have no mass, they can still transfer a small amount of momentum. So, when photons hit the solar sail, the craft is pushed very slightly away from the Sun. Over time, if a spacecraft is out in space without any atmosphere to encumber it, it could potentially accelerate to incredibly high speeds.

A spacecraft with a solar sail wouldn't need to carry fuel and so could theoretically travel for longer periods of time, as it wouldn't need to refuel.

But LightSail 2 is in orbit around the Earth. As the spacecraft swings its sails into the sunlight, it raises its orbit by as much as a few hundred meters a day. But the small spacecraft doesn't have the means to tilt the sails precisely enough to prevent lowering its orbit on the other side of the planet. Eventually, LightSail 2 will dip far into the Earth's atmosphere to succumb to atmospheric drag. It will deorbit and burn up.

Previously:
LightSail 2 Spacecraft Successfully Demonstrates Flight by Light
Drama in Low-Earth Orbit as LightSail 2 Deploys its Sails
Planetary Society Receiving Data From LightSail 2
One Legacy of Carl Sagan May Take Flight Next Week—a Working Solar Sail

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