Staged microgravity deployment of a pressurizing scale model spacecraft

The experiment described in this paper was conducted with the goal of obtaining quantitative pressure and motion data for inflation of an unfolding scale-model spacecraft structure in an environment free of gravity. The experiment included a series of staged deployments of two identical unfolding, inflating scale-model solar concentrators, each consisting of three struts and a torus. The experiment was conducted aboard NASA's KC-135 aircraft. Internal pressure was simultaneously measured at six locations in the deploying structure, at the bottom and top of each strut. Deployment motions tracked in video sequences were compared to measured pressures. Common characteristics of pressurization and motion were seen in eleven staged deployments, including phases of near-constant pressure as the internal volume increased and of increasing pressure as volume remained constant. Also, pressurization of the struts shows equalization of pressure occurs at different times for different struts, possibly explaining asymmetric motions during deployment.