A significant number of satellites in orbit are presently unused because some of their components are not functional. In many cases, a good solution would be to use an unmanned on-orbit servicing satellite in order to repair the existing satellite at a fraction of the cost of a new satellite. In order to perform the automated tasks, new tools must be developed. One of the tools must be able to remove and reinstall the thermal blankets that cover the satellites in order to provide access to the components underneath. In this context, the development of a Blanket Manipulation Tool (BMT) has been proposed by MacDonald Dettwiler and Associates Ltd (MDA) in cooperation with the Canadian Space Agency (CSA).
Fig. 1 : Satellite.
The BMT should be able to slide under a thermal blanket attached with velcro and grasp it in order to pull it off and put it back. In this project, a plastic prototype of the BMT, illustrated in Figure 2, was developed, built and tested. In order to confirm the correct grasp of the thermal blanket and provide information on the external contacts, the jaws of the grasping device include sensors. Also, in order to be able to apply a controlled force and prevent damage to the tool, even if the robotic arm that will handle the BMT will have a limited precision and no Force Moment Accomodation (FMA), compliant mechanisms are included. The plastic prototype demonstrated the functionality of the features developed, mainly: grasping, compliance and sensing. The next task will be the development of a metal prototype.
Fig. 2: Prototype of the Blanket Manipulation Tool.
Video clip
The following video segment shows the Blanket Manipulation Tool in operation.