Johns Hopkins APL Engineer Takes Helm of NASA Solar Sail Concept

May 27, 2022

Johns Hopkins APL Engineer Takes Helm of NASA Solar Sail Concept

NASA is further investing in the development of a new concept for a sail that uses sunlight to propel spacecraft through space, the agency announced May 24. Called the Diffractive Solar Sailing project, the concept now enters Phase III under the NASA Innovative Advanced Concepts (NIAC) program, which will provide the project with $2 million over the next two years.

Amber Dubill, a mechanical engineer at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, will lead the Diffractive Solar Sailing team, which includes experts in optics, aerospace, traditional solar sailing and metamaterials.

"I am beyond excited to be joining the imaginative and creative group of people that make up the NIAC fellows," Dubill said. "I have actually participated in different NIAC projects since 2017 in various capacities, but being able to lead one is an honor that I could have only dreamed of."

The researchers will continue developing the technology in preparation for a potential demonstration mission orbiting the Sun's poles - a region that has never been seen before.

Much like sails capture the wind to propel boats or ships across the sea, solar sails use pressure exerted by sunlight to push spacecraft through space. Essentially giant mirrors, these solar sails use the tiny bit of momentum that photons of light impart as they bounce off the sail's reflective surface, providing a low-cost way to accelerate spacecraft to speeds that wouldn't be possible with just rockets and a stash of fuel.

Reflective solar sail designs, however, tend to run large and thin and are limited by the direction of sunlight, creating trade-offs between power and navigation. Diffractive Solar Sailing instead takes advantage of a different property of light called diffraction - the spreading or bending of light around obstacles.

Using small gratings embedded within thin films, the sail diffracts light to provide a force that will be more efficient for making orbital maneuvers without having to move a large, flimsy structure, Dubill explained.

"Diffraction essentially lets you tailor the angle at which the incoming light is redirected," she said, resulting is a spacecraft that can take better advantage of sunlight without sacrificing maneuverability. It also produces a notable visual difference from the shiny tinfoil look of solar sails: It creates a rainbow holographic effect similar to what you see when holding a CD up to the Sun.

Under its previous awards, the team designed, created and tested various types of diffractive sail materials. During this new phase, however, the team aims to actually develop the diffractive sail itself as well as design a future solar polar orbiter constellation mission that will use the diffractive sails.

"While this technology can improve a multitude of mission architectures, it is poised to significantly impact the heliophysics community's need for unique solar observation capabilities," Dubill said. "Through expanding the diffractive sail design and developing the overall sailcraft concept, the goal is to lay the groundwork for a future demonstration mission using diffractive lightsail technology."

NIAC is funded by NASA's Space Technology Mission Directorate, which is responsible for developing new cross-cutting technologies and capabilities needed to achieve the agency's current and future missions.

Media contact: Michael Buckley, 240-228-7536, [email protected]

The Applied Physics Laboratory, a not-for-profit division of The Johns Hopkins University, meets critical national challenges through the innovative application of science and technology. For more information, visit www.jhuapl.edu.