Innovators at NASA’s Glenn Research Center have developed lightweight and reliable mechanisms based on shape memory alloys (SMAs) for small satellites such as CubeSats. SMAs have a unique ability to effect a reversible phase transformation, so that they can withstand being severely deformed and recovered repeatedly. Glenn’s innovation, flown in a successful space mission, uses SMA components in actuators and hinging elements to improve retention, release, and deployment of crucial structures such as solar arrays.
Compared to standard devices, the SMA-based mechanisms are much smaller and lighter, do not produce debris, and require minimal power to operate, meeting the rigorous power budget for CubeSats. These SMA-based components are a key breakthrough for CubeSats and other small satellites, where their small size and weight, reusability, and reliability are mission-critical. In addition, these mechanisms can be scaled up, so their benefits can be realized in larger spacecraft as well.
Most spacecraft feature release, retention, and deployment devices as key components, because these devices achieve on-demand configurability of solar panels, probes, antennas, scientific instruments, fairings, etc. Until now, designing and using such devices in small spacecraft has been a challenge because their mass, volume, and power requirements are significant and can impose design constraints. CubeSats, in particular, often need to deploy several structures (such as solar arrays) simultaneously, which prior-art deployment devices have not been able to manage effectively.
Glenn’s innovation embeds SMAs within the components so the structures can be retained during launch, then released and deployed in orbit. The release and retention device is controlled by an SMA activated pin puller to disengage the release plate from the hooks holding the solar arrays. Once released, the SMA hinge is passively enabled to the deployed state. When ready on orbit, the mechanism is commanded to release and electrical power is sent to the SMA actuator, releasing the component to its deployed state. The component is deployed to its final position through the use of hinges that are activated passively with SMA spring strips. The retention and release device and hinge are substantially smaller and lighter than deployment mechanisms have ever been and can deploy simultaneously with great reliability.