Session
Session VI: FJR Student Competition
Location
Utah State University, Logan, UT
Abstract
Deployable structures increase mission capabilities and this applies particularly to microspace missions which are subjected to tight volume constraints. Nonetheless, these deployable structures come at an increase in risk and financial costs. In fact, problems associated to deployable solar wings are one of the main contributors to early mission failure. This paper presents the development of a reliable low-cost hold-down and release mechanism for a two-segment small satellite solar wing. This mechanism was valuable in the effort of bringing the overall solar wing cost down by 30% to 60% in comparison to what is commercially available. Its main components are the ejector release mechanism, the cups and cones, and the hold-down bracket. The ejector mechanism is a commercial off-the-shelf component with flight heritage. The cups and cones lock the panels together in-plane and support the in-plane loads. They were sized to support the launch loads while placing careful consideration on preventing them from impeding deployment. The bracket houses a spring-loaded bolt which is preloaded to keep the panels stowed. Its arched profile reduces shear forces on the inserts it mounts to, ultimately enabling a greater preload to be applied. Finite element analysis was performed to ensure positive strength margins. A thermal strain analysis verified that the coefficient of thermal expansion mismatch that is present within the mechanism does not damage the neighbouring solar cells. Thermal tests were executed and successfully verified that there were no risks associated to thermal strains on the cells and that the wing can fully deploy at operational temperature extremes. Finally, vibration tests were performed with the mechanism mounted to the satellite. The wing remained stowed for the entirety of the test with negligible shift in its stowed and deployed natural frequencies, proving that the components were sized properly. The wing was successfully deployed after the tests and inspections of the cups and cones showed minimal wear on the contact surfaces.
Low-Cost Hold-Down and Release Mechanism for Small Satellite Deployable Solar Wings
Utah State University, Logan, UT
Deployable structures increase mission capabilities and this applies particularly to microspace missions which are subjected to tight volume constraints. Nonetheless, these deployable structures come at an increase in risk and financial costs. In fact, problems associated to deployable solar wings are one of the main contributors to early mission failure. This paper presents the development of a reliable low-cost hold-down and release mechanism for a two-segment small satellite solar wing. This mechanism was valuable in the effort of bringing the overall solar wing cost down by 30% to 60% in comparison to what is commercially available. Its main components are the ejector release mechanism, the cups and cones, and the hold-down bracket. The ejector mechanism is a commercial off-the-shelf component with flight heritage. The cups and cones lock the panels together in-plane and support the in-plane loads. They were sized to support the launch loads while placing careful consideration on preventing them from impeding deployment. The bracket houses a spring-loaded bolt which is preloaded to keep the panels stowed. Its arched profile reduces shear forces on the inserts it mounts to, ultimately enabling a greater preload to be applied. Finite element analysis was performed to ensure positive strength margins. A thermal strain analysis verified that the coefficient of thermal expansion mismatch that is present within the mechanism does not damage the neighbouring solar cells. Thermal tests were executed and successfully verified that there were no risks associated to thermal strains on the cells and that the wing can fully deploy at operational temperature extremes. Finally, vibration tests were performed with the mechanism mounted to the satellite. The wing remained stowed for the entirety of the test with negligible shift in its stowed and deployed natural frequencies, proving that the components were sized properly. The wing was successfully deployed after the tests and inspections of the cups and cones showed minimal wear on the contact surfaces.
