Bill Nye-Backed LightSail 2 Successfully Demonstrates Light-Powered Space Flight

A new spacecraft is circling around Earth. But LightSail 2 doesn't have rockets or even solar panels. Instead, the fuel-free vehicle is soaring through space using the power of the sun's light.

LightSail 2 was launched June 22 on a Falcon Heavy Rocket from SpaceX, Elon Musk's space exploration company. It was developed by The Planetary Society, a non-profit headed by Bill Nye that's devoted to space exploration. The LightSail project was crowdfunded on Kickstarter, raising an impressive $1.24 million.

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In this photo taken in 2005 at the 25th anniversary gala for The Planetary Society, current CEO Bill Nye (far left), poses with Star Trek star Nichelle Nichols, astronaut Buzz Aldrin and legendary science fiction author Ray Bradbury. Albert L. Ortega/Getty

Weighing a mere 11 pounds, LightSail 2 is relatively small for a spacecraft. And has just two major components: A solar sail and a CubeSat, a module designed at Cal Poly that's about the size of a loaf of bread. It's powered by photons from the sun hitting the sail—much like a sailboat uses the wind.

"Light from the sun—or possibly lasers in the future—propels the spacecraft," LightSail program manager Bruce Betts told Newsweek in May. "Particles of light carry momentum so they push on things. In our everyday life, we never notice this because the push is so small. Even subtle air currents will overwhelm the effect."

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The LightSail 2 took this photo on its flight, showing the craft's aluminized Mylar sail with the sun peeking through. Light from the sun literally pushes the craft through space, much like wind powering a sailboat. The Planetary Society

"The push on the entire LightSail 2 sail is only the equivalent of the weight of a housefly on Earth," he added. "But if you put a spacecraft in the vacuum of space, the light pressure effect becomes significant, particularly if you deploy a shiny sail and keep your spacecraft mass as low as possible."

LightSail 2's sail—which is 350 square feet, or about the size of a boxing ring—was unfurled last week. Since then, Planetary Society engineers have been steering the spacecraft on its journey through the heavens. The mission team confirmed LightSail 2 hit the highest point of its orbit—about 1.2 miles above the Earth—in the past four days, something that could only be done via solar sailing.

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This animation shows how the LightSail 2 raises its orbit. Josh Spradling/The Planetary Society

Twice each orbit, the sail rotates 90 degrees: When LightSail 2 approaches the sun, the sail is turned on-edge to avoid being pushed by photons. As it moves away from the sun, the sail turn perpendicular to the light, getting an extra push.

"For me, it's very romantic that you'll be sailing on sunbeams," Nye told The New York Times.

Over the next month, engineers will try to get the craft to orbit even higher above the Earth. After that, LightSail 2 will begin to deorbit, and burn up on reentry to the atmosphere in about a year.