Satellite refuelling system and method

Abstract

The present invention provides a method, system and apparatus for robotic refuelling of satellites. The system may include a dedicated refuelling satellite launched directly from either earth, or alternatively it could be launched from another larger mother spacecraft or space station in which the refuelling satellite is ferried into space in the case of the larger space craft or it may be stored on the space station until needed from which it can be launched. The system includes a robotic arm, suitable tools which can be affixed to the end effector of the robotic arm required for accessing, opening and closing the fuel fill valve on the satellite being serviced, storage and retrieval stations on a tool caddy on which the tools and various fuel fill valve caps are stored. The system is under teleoperation by a remotely located operator, for example located on earth, in the mother station or in the space station. Cameras are included focussed on the robotic arm and end effector and images are transmitted to the operator to allow the operator to direct and control the refuelling procedure. The system may also be configured to be operated autonomously under computer control.

Description

CROSS REFERENCE TO RELATED U.S PATENT APPLICATION[0001]This patent application is a continuation of application Ser. No. 12 / 073,795, which claims priority benefit from U.S. provisional patent application No. 60 / 905,827 filed on Mar. 9, 2007 entitled ROBOTIC SATELLITE REFUELLING METHOD AND SYSTEM, filed in English, which is incorporated herein in its entirety by reference.FIELD OF THE INVENTION[0002]The present invention relates to a satellite refuelling system and method for refuelling satellites.BACKGROUND OF THE INVENTION[0003]Many geosynchronous orbit communication satellites currently in operation were designed with a finite amount of fuel and were not designed for the possibility of being refuelled. The design philosophy relied upon replacement of the satellites after they had exhausted the on-board fuel supply. In view of the expense of replacing satellites, it would be very advantageous to be able to refuel communication satellites which are either near their end of life, or ...

AI Technical Summary

Benefits of technology

[0015]In another embodiment, the refuelling system may be equipped with an artificial vision function which is used to register the worksite in the vicinity of the fill-drain valve, providing relative positions between the servicing arm / tool combination with the valves. The refuelling system is then controlled in a supervised autonomous manner using an updated model of the worksite derived from the artificial vision function registration information. The system disclosed herein may also be used for fuelling for the first time satellites prior to launch, thereby eliminating or at least reducing the risk of a refuelling technician being exposed to the toxic fuel in the event of a mishap.

Problems solved by technology

Many geosynchronous orbit communication satellites currently in operation were designed with a finite amount of fuel and were not designed for the possibility of being refuelled.

Some satellites suffer from primary propulsion system failures soon after they are launched.

The key technical difficulty is that these satellites were not designed for robotic servicing, and it is not generally accepted that such missions are technically possible.

Thus, accessing these fill and drain valves remotely presents several major challenges and would involve several operations, each of which is difficult to accomplish robotically including: cutting and removal of the protective thermal blankets, removal of several lockwires hand wrapped around the valves, unthreading and removing outer and inner valve caps, mating the fuel fill line to the valve nozzle, mechanically actuating the valve, and when refuelling is complete, replacing the inner valve cap.

Robotic capture and servicing of existing geostationary spacecraft has never been demonstrated.

However a gap exists in the technologies required to service or re-fuel an un-prepared satellite in orbit.

To date there have been no technologies disclosed that can solve the problem of accessing the fuel system of an unprepared satellite for the purpose of replenishing station keeping fuel.

The technologies required to access the target spacecraft's fuel system for the purposes of refuelling still have a very low technology readiness level, and are generally considered to be the main obstacle to a successful servicing mission.

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