Satellite Docking System

HTR approach to satellite docking

The proposed system relates to a service satellite having a docking unit consisting of a telescopic arm mounted on a 6-DOF parallel manipulator and two additional gripping arms. The telescopic arm deploys from the end effector plate of the 6-DOF manipulator and is equipped with a rapid closure pair of digits at its free extremity. The telescopic arm provides a large work space for capturing the launch adaptor ring of a client spacecraft even in the presence of client tumbling. The 6-DOF parallel manipulator is equipped with force sensors and can accommodate post capturing relative motion through active compliance control and controlled de-tumbling avoiding the generation of high forces in the telescopic arm and between the vessels. After relative rate annihilation, the telescopic arm retracts and the client ring is secured on the end effector plate of the 6-DOF manipulator with the help of a pair of clamps. When the ring is secured and clamped on the end effector plate, the two additional fixing arms deploy and secure a rigid connection on the launcher ring on two, equally spaced locations on the ring. In that way the docking connection between the service satellite and the client finally comprises three equally spaced locations on the launcher ring, guaranteeing the stack rigidity needed for either station keeping, servicing operations or de-orbiting thruster burns.

Safe distance approach using a 1.5m deployable arm, with a fast grasping tool at its end

Soft capturing, de-tumbling and collapse of the arm

Deployment of clamping grippers and secondary fixture for rigid capturing and stabilization

HTR Test and validation infrastructure

The proposed system is tested on a zero-gravity simulator multi-DOF table, backed by and end-to-end dynamic simulator platform. Over 3000 tests verify and validate all approach, capturing, relative rate and tumbling scenarios.