System and tool for accessing satellite fill/drain valves during propellant resupply

Patent metadata

Field	Value
Publication number	US-9688422-B2
Application number	US-201514826444-A
Country	US
Kind code	B2
Filing date	Aug 14, 2015
Priority date	Dec 5, 2011
Publication date	Jun 27, 2017
Grant date	Jun 27, 2017

Abstract

Herein is disclosed a tool, system and method for refueling on-orbit spacecraft. The tool and system are configured to allow for resupply of spacecraft configured to be propelled by either a bipropellant (oxidizer and fuel) or a monopropellant (typically hydrazine). The refueling tool is particularly suited for resupply of satellites not originally prepared for refueling but the system may also be used for satellites specifically designed for refueling.

First claim

Therefore what is claimed is:

1. A system mounted on a servicing spacecraft for transferring fluid between one or more selected fluid storage tanks on the servicing spacecraft and a client satellite, the client satellite including one or more fluid storage tanks and a fill/drain valve associated with each of the one or more fluid storage tanks, each fill/drain valve having rotatable features and static features coaxially aligned along a first axis, comprising:
a) a positioning mechanism, an end effector mounted on the positioning mechanism, the end effector being coupled to the one or more selected fluid storage tanks;
b) a tool including
a housing,
a grapple fixture mounted on said housing configured to be grasped by said end effector,
a fluid selection and coupling mechanism mounted in said housing and configured to be coupled to the end effector for coupling the one or more fluid storage tanks on the client satellite to the one or more selected fluid storage tanks mounted on the servicing spacecraft,
a wrench permanently fixed within said housing including at least first and second adjustable wrench mechanisms coaxially aligned one on top of the other along a second axis, one of said first and second adjustable wrench mechanisms being configured to engage the rotatable feature and the other being configured to engage the static feature while simultaneously and adjustably conforming to a size of the rotatable and static features for opening and closing each fill/drain valve on the one or more tanks and mating the fluid selection and coupling mechanism to the at least one fill/drain valve on the client satellite;
an actuator mounted in said housing coupled to the fluid selection and coupling mechanism and the wrench;

c) a sensor system for at least determining a relative displacement between said tool and each fill/drain valve on the one or more fluid storage tanks; and
d) a control system in communication with said sensor system, said positioning mechanism, said end effector and said actuator for controlling operation of said positioning mechanism, said end effector and said tool based on feedback from said sensor system.

2. The system according to claim 1 wherein said actuator includes
a motor,
a gear shifter, the motor being coupled to the gear shifter,
a differential gearbox mounted in said housing coupled to said gear shifter and at least first and second output shafts, the gear shifter being configured to transmit torque from said motor to said differential gearbox, said differential gearbox being configured to transmit said torque received from said gear shifter to said at least first and second output shafts, the gear shifter being configured to be engaged to said fluid selection and coupling mechanism for moving said fluid selection and coupling mechanism between at least two positions in said housing,
said first adjustable wrench mechanism being coupled to said first output shaft for transmitting torque received by said first output shaft from said gearbox to a first object engaged by the first adjustable wrench mechanism, said second adjustable wrench mechanism being coupled to said second output shaft for transmitting torque received by said second output shaft from said gearbox to a second object engaged by the second adjustable wrench mechanism, the gearbox being configured to split the torque received by the gear shifter evenly between the first and second adjustable wrench mechanisms to apply equal and opposite forces to said first and second objects; and
wherein said first object is the rotatable feature of a fill/drain valve such that the first adjustable wrench mechanism configured to engage the rotatable features of the fill/drain valve of the second satellite to apply bi-directional torque to the rotatable features, and the second object is the static feature of the fill/drain valve such that the second adjustable wrench mechanism reacts the torque on the static features on the fill/drain valve.

3. The system according to claim 2 wherein the at least one fill/drain valve includes a secondary seal fitting with associated rotatable features, wherein said wrench includes at least a third adjustable wrench mechanism being aligned coaxially with the first and second adjustable wrench mechanisms, said gearbox including a third output shaft, said third output shaft being coupled to said third adjustable wrench mechanism, said third adjustable wrench mechanism being configured to engage the associated rotatable features of the secondary seal fitting to apply bi-directional torque thereto while the second of the adjustable wrench mechanisms reacts this bi-directional torque on the static features on the fill/drain valve.

4. The system according to claim 3 wherein said differential gearbox is a shifting differential gearbox in which an operator can selectively shift between differentially paired output shafts.

5. The system according to claim 3 wherein said differential gearbox is a shifting differential gearbox in which an operator can selectively shift between said first and second output shafts and said second and third output shafts.

6. The system according to claim 3 wherein each adjustable wrench mechanism includes a housing having a rotational axis, a pair of opposed nut cams pivotally mounted each to a toothed cam lock, said nut cams each including a pawl member, said cam locks being translationally mounted to a cam ring, said cam ring coaxially mounted in said housing and being rotationally movable with respect to said housing, a detent spring mounted between said cam ring and said housing to restrict movement of said cam ring, a toothed drive ring having inner and outer toothed surfaces mounted in said housing and being rotatable with respect to said housing, said pawl member being engaged with said toothed drive ring so that when said toothed drive ring is rotated by an output shaft from said differential gearbox, said nut cams are rotationally driven until they contact opposing outer surfaces of a faceted rotatable element, at which point said toothed cam locks slide radially outward to engage a toothed inner surface of said toothed drive ring thereby locking the drive ring and the cam ring together to permit torque applied by said output shaft to be transmitted to said faceted surface.

7. The system according to claim 6 wherein said each nut cam includes a cam face, and wherein when said adjustable wrench mechanism is rotated within said housing over a fill/drain valve the cam faces on the two nut cams move towards each other until they contact the features on the fill/drain valve.

8. The system according to claim 1 wherein the positioning mechanism is configured to carry one or more fluid lines which are coupled to the one or more selected fluid storage tanks, and wherein the end effector is coupled to the one or more fluid lines on the positioning mechanism.

9. The system according to claim 8 wherein the end effector includes at least one fluid coupling and a coupling actuator for moving the at least one fluid coupling, and said fluid selection and coupling mechanism includes at least one fluid coupling attached on an exterior of the housing, and wherein the end effector and the housing are configured such that when the end effector grips the grapple fixture and the actuator is activated the at least one fluid coupling on the end effector mates with at least one fluid coupling on the exterior of the housing.

10. The system according to claim 9 wherein the end effector includes at least one electrical connector connected to a power source on the servicer satellite, and wherein said housing includes at least one electrical connector located on an exterior of the housing, and wherein th

Assignees

• Macdonald Dettwiler & Associates Inc

Inventors

• Roberts Paul
• Hay Gavin
• White Jason
• Sprawson Geoffrey

Classifications

• B64G4/00 Primary

  Tools specially adapted for use in space · CPC title

• B64G1/1078 Primary

  Maintenance satellites (refuelling in space B64G1/4024) · CPC title

• B64G1/402

  Propellant tanks; Feeding propellants · CPC title

• B64G1/4021

  Tank construction; Details thereof · CPC title