Environmental Testing and Analysis of a Boom Deployment Mechanism for Gossamer-2

DLR is currently developing several mechanisms for boom and membrane deploying spacecrafts. Two of the related projects are dedicated to solar sailing technology to investigate this promising alternative space propulsion technology. One supports the Gossamer-1 mission in which a 5 m by 5 m solar sail technology demonstrator is developed; the second is the planned, up scaled successor Gossamer-2 with a size of 20 m x 20 m. One goal of the development process in these missions is to achieve a deployment mechanism, that can be scaled up and used in future missions with larger sail areas (Gossamer-2: 20 m x 20 m, Gossamer-3: 50 m x 50 m) spanned out by larger booms. Within the EU funded DEPLOYTECH project the well matured Gossamer-1 boom deployment mechanism has been adapted for the Gossamer-2 size. Therefore, DLR scaled up and redesigned the deployment mechanism to work with the larger 14 m CFRP boom dedicated for the Gossamer-2 size spacecraft. In this paper the concept and design of the up-scaled boom deployment mechanism are described, followed by the main part that addresses the environmental testing performed on the prototype of the up-scaled boom deployment unit. The objectives, the test procedure and the results from thermal-vacuum, vibration and functional deployment tests are presented in detail. Furthermore, FE-Analyses for simulating the vibration tests are performed. In this regard the used FE-model is described and the obtained results are shown in detail. Consequently, the simulated and measured results are compared and discussed.