Abstract
The space industry has long benefited from the engineering innovations of deployable structures. Deployable structures are incrementally being used and proposed as the main structure for higher risk missions owing to the potential cost savings made in launching smaller spacecraft. To increase the revisit time of Earth observation satellites it is proposed that multiple small satellites with on-board deployable telescopes can be used in a constellation. The structure separating the primary and secondary mirrors of any deployable telescope must be sufficiently stiff so as to avoid distorted images from on-board micro-vibrations. In this paper the stiffness characteristics of three types of tape spring deployer are investigated using analytical, finite element and experimental methods. A deployer that clamps the root of a tape spring performs well in terms of the stiffness, but suffers due to larger stowed volume necessary. Partially restraining the root allows a smaller stowed volume to be used, but compromises the stiffness. An analytical resilient beam model is employed to predict the stiffness of tape springs deployed in this manner, and is shown to be in good agreement with experiment. A novel deployer is presented that aims to combine the benefits of the two previous deployers. The partially restrained deployer is identified as the most promising design via a trade matrix.