Spacecraft are propelled without fuel using solar sails

NASA is currently testing a sail system that harnesses solar energy to propel spacecraft through space. The Advanced Composite Solar Sail System (ACS3), which is the world’s most advanced solar sail spacecraft, was launched on April 24 at 6:32 a.m. using Rocket Lab’s Electron booster from Launch Complex 1 in Mahia, New Zealand. The ACS3 is part of NASA’s Beginning Of The Swarm mission and, despite being the size of a microwave, it can deploy its thin plastic sail in about 25 minutes to cover 80 square meters with a 7-meter stretchable pole. This system marks an important advancement in making solar sails lighter and more stable.

Currently positioned in a sun-synchronous orbit 966 meters above Earth, the ACS3 will deploy in the coming weeks to demonstrate technology that could power deep space missions without the need for rocket fuel. By utilizing the pressure from solar energy, the thin sail can propel the spacecraft at high speeds, similar to a sailboat. The ACS3 project is specifically testing a design made of flexible polymer composite materials reinforced with carbon fiber.

Once deployed, the tensioning poles of the solar sail act like sailboat masts, keeping the sails taut to collect solar energy. The tension poles are designed to fold compactly for stowage and are built to withstand temperature fluctuations and endure extended missions. NASA is also planning to design a larger solar sail equivalent to the size of a basketball court, which would require an extensive extension pole system.

To address this challenge, NASA has rolled the stretch pole made from the new composite material into a large, envelope-sized package. The pole will be opened using a pulling system similar to a tape roll to minimize the risk of getting stuck. After setting up the tensioning pole, onboard cameras will record the process to evaluate the new solar sail design and measure its thrust on the spacecraft’s orbit.

Following the subsystem testing period, the ACS3 will conduct tests to raise and lower its orbit. If successful, NASA plans to scale up the design for interplanetary travel within the solar system.