Comparison of candidate mechanism concepts for a deployable space telescope

The future of spaceborne observations is strongly oriented toward miniaturization of payloads without reducing their performances. In this framework telescopes equipped with deployable structures would guarantee either an improvement of the performances or a considerable volume reduction which, due to the limitations on the launcher, translates into a lower cost of in-orbit commissioning. This paper aims at comparing possible mechanism layouts for a deployable space telescope designed for Earth observation in the infrared spectrum. The design considers a classical Cassegrain telescope and aims at packaging the secondary mirror as close as possible to the primary; the trade-off analyses among different technological solutions and configurations are presented. This is a preliminary study performed in the framework of DORA (Deployable Optics for Remote sensing Applications), a project aiming at developing a deployable telescope for minisatellites, and concludes with the assessment of the most feasible layouts which are going to be considered in the next phases of the project.