Ground verification of deployment dynamics of large mdeployable space structures

This paper describes a precise verification procedure for antenna-deployment mechanisms using ground-deployment test data. Ground-deployment tests are carried out for a communication antenna reflector for the Engineering Test Satellite VI (ETS-VI). The antenna-deployment mechanism studied consisted of a bearing, a helical spring, a chassis, and a latch mechanism. The characteristics of individual parts were measured under, space and ground conditions. Then the initial characteristic of a deployment mechanism is statistically predicted. Ground verification of a deployment mechanism is usually difficult because of atmospheric and gravitational effects especially at the system level. Therefore, a new verification procedure is employed. Two kinds of suspending system are developed to compensate for gravity effects. The characteristics of a deployment mechanism can be estimated by identifying system parameters for the equation of deployment motion. This estimation procedure covers all development stages, so that a characteristic history of a deployment mechanism can be easily obtained. Atmospheric and gravitational effects on deployment motion are taken into account as system parameters. It is clarified that all mechanical parts retain their initial characteristics during assembly and environmental testing.