Data Analysis of a Tethered SpaceMail Experiment

摘要

The Second Young Engineers' Satellite is a 36 kg student-built experiment that piggybacked on the Foton-M3 microgravity platform in September 2007. Its mission was tethered SpaceMail: a propellantless sample return from an orbital platform. The experiment included a two-stage tether deployment, leading to a swing of the tether toward the local vertical, in which finally a capsule was released from the bottom of the tethered system into a reentry trajectory. The first deployment stage of 3.4 km was completed within about 20 m accuracy. The second stage started on time and the end mass initially accelerated nominally. Then, due to an electrical problem, the tether was deployed to its full length of 31.7 km, rather than to the target length of 30 km. It was nevertheless released at the proper time and at a near-nominal in-plane angle. Data analysis shows that the Second Young Engineers' Satellite scientific objectives were achieved. The two-stage deployment trajectory could be reconstructed and the capsule trajectory could be estimated. The proper performance of the deployer hardware and controller was demonstrated, and tether physical properties were also determined. Finally, simulation and test results could be matched to flight data, providing both confidence and recommendations for preparation of future tether missions.