NASA looks to solar sails as a way to power future missions

A NASA-funded project is developing new technologies that would allow a spacecraft to fly through the cosmos propelled entirely with solar sails that “bend” light.

The agency announced Tuesday that it will provide $2 million over two years to the Diffractive Solar Sailing project, which is investigating ways to use energy from the sun to steer and power vehicles in space.

The project is part of the NASA Innovative Advanced Concepts program, which funds ideas that could be used on future missions through multiple phases of research and testing.

“As we venture farther out into the cosmos than ever before, we’ll need innovative, cutting-edge technologies to drive our missions,” NASA Administrator Bill Nelson said in a statement.

NASA has long been interested in solar sail technology because it offers a cost-effective alternative to traditional propulsion systems, without requiring a spacecraft to carry heavy and expensive fuel onboard. Rather, vehicles equipped with solar sails could be powered with a resource that is both abundant and virtually inexhaustible: sunlight.

Solar sails use momentum from sunlight to travel through space — similar to the way sailboats use wind to carry them across the sea.

Previous solar sail projects largely used mirror-like surfaces reflect particles of light, called photons. As photons hit the sail, they transfer their energy and propel the spacecraft along. While effective, this technique has its drawbacks because the vehicle’s mobility is limited by the direction of the sunlight.

To get around this, the Diffractive Solar Sailing project is developing sails that essentially “bend” light to boost both power and maneuverability. Small gratings embedded in the thin material of the sails would capture photons and spread the light as it passes through the openings. This would allow a vehicle to take advantage of momentum from photons regardless of the natural direction of the sunlight.

The technology could be used to navigate to positions that would be tricky using conventional propulsion systems, including missions to orbit around the sun’s poles, said Amber Dubill, a mechanical engineer at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, who is leading the project.

“Diffractive solar sailing is a modern take on the decades old vision of lights,” Dubill said in a statement. “With our team’s combined expertise in optics, aerospace, traditional solar sailing, and metamaterials, we hope to allow scientists to see the sun as never before.”

NASA said the new round of funding will be used to further develop the solar sail technology in preparation for a possible demonstration mission in the future.

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