Space exploration is driven by technology – sometimes literally in the case of propulsion technologies. Solar sails are one of those propulsion technologies that has been getting a lot of attention lately. They have some obvious advantages, such as not requiring fuel, and their ability to last almost indefinitely. But they have some disadvantages too, not the least of which is how difficult they are to deploy in space. Now, a team from NASA’s Langley Research Center has developed a novel time of composite boom that they believe can help solve that weakness of solar sails, and they have a technology demonstration mission coming up next year to prove it.
The mission, known as the “Advanced Composite Solar Sail System” (ACS3) mission is designed around a 12U CubeSat, which measures in at a tiny 23cm x 23 cm x 34 cm (9 in x 9 in x 13 in). The solar sail it hopes to deploy will come in at almost 200 square meters (527 sq ft), and both it and its composite booms will fit inside the CubeSat enclosure, which is not much larger than a toaster oven.
The booms themselves are made out of a novel composite that is 75% lighter than previous deployable booms, while also suffering from only 1% of the thermal distortion that previous metallic booms were subjected to. They also conveniently roll into a 18 cm (7”) diameter spool that can be easily stored and easily deployed once the CubeSat is in space.
Its deployment mechanism still requires power, however, so the ACS3 mission will use a small solar panel to collect enough power to enable that deployment. But once it is fully unfurled, the mission will switch to a technology demonstration of actually adjusting the CubeSat’s orbit using only solar radiation pressure – the driving force of solar sails.
Solar sails themselves are only as effective as their size allows them to be – larger sizes means more radiation pressure and faster acceleration. Therefore, the team behind the composite booms are also developing a larger boom system that would allow them to deploy solar sails that will come in at a whopping half an acre (2,000 sq meters). Its spools would need to be slightly longer, but the cost to benefit ratio is huge.
These booms could also be used outside of the world of solar sails as well. Other obvious uses include structural components for lunar bases of communication towers, as scaffolding for space construction sites, or as ladders on space stations. Materials underpin so many aspects of human endeavor that a novel, light, thermally resilient material can find myriad uses both on and off Earth.
But before those uses are realized, it must prove itself in its first use case – the ACS3 mission. The mission will also carry cameras on board to observe the boom’s deployment process, as well as the quality of the sail in space. With luck, there will be some pretty pictures of a large solar sail surrounding a CubeSat when the mission launches, hopefully sometime next year.
NASA – Advanced Composite Solar Sail System: Using Sunlight to Power Deep Space Exploration
NASA Techport – Advanced Composite Solar Sail 3 (ACS3)
Space.com – NASA to test new solar sail technology with launch in 2022
Popular Mechanics – NASA’s New Solar Sail Is Unlike Any Other