Design and performance of Astromesh reflector onboard Soil Moisture Active Passive spacecraft

The Soil Moisture Active Passive¹ (SMAP) instrument includes a conically scanning 6-m diameter deployable Astromesh reflector and feedhorn that rotates relative to a de-spun spacecraft at 14.6 RPM. This is the first application of a spinning Astromesh reflector. This paper describes the design and performance of the Reflector/Boom Assembly (RBA) under multiple constraints and requirements that are inherent to a spinning large flexible reflector/structure. The deployed RBA has stringent mass property control and knowledge requirements, structural natural frequency separation requirements, and all other typical ones including the antenna performance. Finally the validation of the design on the ground by analysis/test and its difficulties due to gravity are discussed.