Design and Development of Deployable Mechanism for Prime Focal Antenna

Abstract

Deep space exploration, radio astronomy interplanetary missions and next generation telecommunication require high bandwidth data transmission for effective and un-interruptive communication. This caters to need of launching of large size antenna systems of the order of 3m and above. In satellite system, large antennas are limited due to launch vehicle size which is in range of 2-4 m diameter. Therefore deployable mechanisms are developed to enable large aperture antenna. After the launch vehicle reaches to orbit in the space, the antenna needs to be deployed / unfurled, which consists of transition from mechanism to structure. After deployment, the geometric position of points of antenna surface must be within close tolerance limit, which demands lot of precision and accuracy for achieving perfect reflective surface. Domain study has been undertaken for deployable antennas of satellite. Various types of deployable antennas are explored under this work. Typically prime focal types of deployable antennas are focused in this dissertation. A six bar planner mechanism and seven bar spatial mechanism is presented as a various option of the deployment mechanism. Detail study is carried out for kinematics of mechanism used for prime focal antenna. Design for manufacturing (DFM) and design for assembly (DFA) are taken into consideration. Prototype for six bar mechanism and seven bar spatial mechanism are developed. Deployment process of six bar mechanism and seven bar spatial mechanism are tested. Torsion spring release mechanism is presented. Prototype for torsion spring release mechanism for two ribs is developed. Deployment process of torsion spring release mechanism is tested using two rib fixtures.