NASA is developing new deployable structures and materials technologies for solar sail propulsion systems for future low-cost deep space missions. Just as a sailboat is propelled by the wind in a sail, solar sails use the pressure of sunlight for propulsion, eliminating the need for conventional rocket fuel.
NASA’s Advanced Composite Solar Sail System (ACS3) technology demonstration uses composite materials (or a combination of materials with different properties) in its novel and light arms that are deployed from a CubeSat. Data obtained from ACS3 will guide the design of future larger-scale composite solar sail systems that could be used for space weather early warning satellites, near-Earth asteroid reconnaissance missions, or communications relays for manned exploration missions.
The primary objective of the ACS3 technology demonstration is the successful deployment of the compound boom solar sail in low Earth orbit. Currently deployed, the four arms of the sail span the diagonals of the square and measure about seven meters long. The square-shaped solar sail measures approximately nine meters per side, or about the size of a small apartment. A set of onboard digital cameras continues to obtain images of the sail to evaluate its shape and alignment and to better understand how the boom technology demonstration worked.
Currently orbiting the Earth, ACS3 can be seen at night from many locations around the world. NASA’s SpotTheSail campaign is available through the NASA app on mobile platforms and can be used to find out when the spacecraft will be visible at a user’s location.
The ACS3’s sails are attached and connected to the spacecraft by booms, which function much like the boom on a sailboat, which connects to its mast and keeps the sail taut. Composite booms are made from a polymeric material that is flexible and reinforced with carbon fiber. This composite material can be rolled up for compact storage, but remains strong and lightweight when unrolled. It is also very rigid and resistant to bending and warping due to temperature changes.
Solar sails can work indefinitelylimited only by the durability of the solar sail materials and the spacecraft’s electronic systems in the space environment. The ACS3 technology demonstration will also test an innovative ribbon reel boom removal system designed to minimize jamming of furled booms during deployment.
Interest in solar navigation as an alternative to chemical and electric propulsion systems continues to increase. Using sunlight to power small spacecraft instead of expendable fuels will be advantageous for many mission profiles and offers flexibility in spacecraft design to help NASA meet its mission objectives in the most efficient manner.
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