On-orbit demonstrations and ground tests push technology forward
By Manan Arya |December 2024
The Spacecraft Structures Technical Committee focuses on the unique challenges associated with the design, analysis, fabrication and testing of spacecraft structures.
From small satellites to envisioned kilometer-
scale systems, the development of deployable structures and in-space manufacturing concepts help lay the foundation for next-generation civil, defense and commercial capabilities in space. This year, several technology demonstrations were conducted, both in space and on the ground, to validate and advance novel concepts.
In April, an Electron rocket launched NASA’s Advanced Composite Solar Sail System, ACS3, to Earth orbit. The goal of the mission is to demonstrate the unfurling of a solar sail via lightweight and thermally stable carbon composite booms. Mission operators confirmed successful deployment of the four 7-meter-long composite booms and the 80-square-meter solar sail in August. Solar sails can generate thrust indefinitely by reflecting sunlight — without needing consumable propellants — and are therefore advantageous for many mission profiles. In previous on-orbit demonstrations, the deployable booms that keep the sail taut have been metallic, and thus susceptible to bending and warping from solar heating. For ACS3, researchers at NASA’s Langley Research Center in Virginia built the booms from carbon composite materials, which are expected to have much lower deflections than metal booms. If successful, ACS3 could lead larger solar sails to be developed and launched in the future.
Ground-based testing of an even larger solar sail system was completed in January, achieving technology readiness level 6. Engineers from NASA’s Marshall Space Flight Center in Alabama, Redwire of Florida and NeXolve of Alabama unfurled one quadrant of a solar sail that when fully deployed will measure 1,650 square meters, the equivalent of four basketball courts. The sail was made of a durable polymer film 2.5 microns thick to save weight and allow for the sail to be accelerated to higher speeds when operating in orbit. Reaching TRL6 means the technology is available to be incorporated into future science mission proposals.
In January, Caltech announced the conclusion of its Space Solar Power Demonstrator mission, comprised of three payloads launched in January 2023 aboard the Momentus Vigoride-5 space tug to test technologies of an envisioned constellation that would collect solar power in space and beam the energy back to Earth. Among the payloads was the Deployable on-Orbit ultraLight Composite Experiment, or DOLCE. For the future power stations, these frames would unfurl on orbit to hold photovoltaic films integrated with radio frequency phased arrays. DOLCE deployment began several months after launch, but the frame jammed on release — an effect addressed during ground testing but exacerbated in space. The Caltech flight team unjammed the structure through remote operation, an activity that underscored the importance of real-world testing while pushing the boundaries of current deployable structures technologies. Caltech said that the mission’s lessons will guide design of the next-generation structure.
In March, Dcubed of Germany secured funding from the European Space Agency and the European Commission to develop and launch in-space manufactured solar arrays. Dcubed focuses on in-space manufacturing of large structures in addition to traditional methods of building such structures on the ground and unfolding them on orbit. The company said this funding will accelerate the development of next-generation solar arrays with support structures that are manufactured directly in space.
