Robotic satellite refueling tool

1. A tool for fuelling an unprepared or partially prepared client satellite which includes a fuel tank, a fuel fill valve and a valve actuation nut on said fuel fill valve used to open and close said fuel fill valve and an access valve cap on said access valve, and optionally includes an oxidizer port on an oxidizer tank having an oxidizer fill valve and a valve actuation nut on said oxidizer fill valve used to open and close said oxidizer fill valve and an access valve cap on said oxidizer fill valve, and wherein said tool comprises;

interchangeable socket modules, a first socket module for removing and replacing said access valve cap on said fuel fill valve, a second socket module connected to said fuel fill line for engaging the fuel fill valve for coupling said fuel fill line to said fuel tank, a third socket module for engaging said access valve cap on said oxidizer fill valve on the oxidizer tank, and a fourth socket module for engaging said oxidizer fill valve for coupling said oxidizer fill line to said oxidizer tank,

a support frame, socket module holder mechanism mounted on said support frame configured to accept said interchangeable socket modules;

a socket drive mechanism mounted on said support frame for actuating said first, second, third and fourth socket modules when seated in said socket module holder mechanism;

a clamping mechanism mounted on said support frame to secure a valve tool to a reaction area on the fuel fill valve and oxidizer fill valve, said clamping mechanism being configured to localize torque generated by said valve tool for ensuring that any reaction torques from the socket drive mechanism are reacted locally to prevent damage to the valve; and

a valve actuation mechanism mounted on said support frame to engage and actuate said valve actuation nut on the fuel fill valve and oxidizer fill valve.

2. The tool according to claim 1 wherein said clamping mechanism is a double four-bar linkage having an elongate clamp-shaft, first and second clamp-links each connected to the clamp shaft, two clamp-fingers pivotally connected together at first ends thereof and a second end of one clamp-finger being connected to said first clamp link, and a second end of the other clamp-finger being connected to said second clamp link, including a gear-motor connected to an end of said elongate clamp-shaft through a flexible coupling for rotating said clamp-shaft about a drive axis of said clamp-shaft, wherein when said gear-motor is actuated, clamp-shaft rotates about ½ turn for the clamp to go from open position to closed position, and wherein the clamp links push and pull respectively the clamp-fingers closed or open in a plane substantially perpendicular to said drive axis, wherein the two clamp-fingers have opposed surfaces for gripping a fuel or oxidizer fill valve stem, and wherein the geometry of said four-bar linkage is selected so that in a fully closed position the clamp links are over the drive axis centre whereby forces applied to the opposed clamp surfaces do not result in torque transmitted to the clamp shaft.

3. The tool according to claim 2 wherein the tool includes a tool caddy which is mountable on the servicing spacecraft, said tool caddy including storage stations for storing and holding the first, second, third and fourth socket modules, and wherein said storage stations for storing and holding the first, second, third and fourth socket modules each include a socket module retaining plate and a tab mounted thereon, and wherein said socket module retaining plate includes a spring ball detent and wherein each of said first, second, third and fourth socket modules include a groove extending around a periphery of said socket module, and wherein said groove on each socket modules is configured to mate with said spring ball detent to hold the socket modules in place in each of the four socket module holder storage stations.

4. The tool according to claim 3 wherein said socket module holder mechanism includes a socket module holder and a module retaining bar rotationally mounted to said socket module holder, and wherein said module retaining bar includes a detent mechanism that holds the retaining bar in either an “open” or “closed” position, and wherein said grooves in said first, second, third and fourth socket modules each have a size sufficient to receive therein said retaining bar, and wherein when said valve tool is fully engaged to the module caddy said module retaining bar is activated by said tab on the socket module retaining plate, and wherein said tab has a portion with a diameter slightly larger than an outer diameter of the socket module holder, and wherein when said valve tool is fully engaged to the module caddy for either retrieving a given socket module from the storage station or returning said given socket module to the storage station, the module retaining bar protrudes outside of this diameter of said tab, and when the socket drive mechanism is activated the module retaining bar will eventually come in contact with the tab on the socket module retaining plate and be toggled to the opposite position, and wherein driving the socket in one direction will lock the socket module in the module holder, and conversely, driving the socket module in the opposite direction will unlock the socket module.