Patent Application
20090001221
The present invention relates generally to spacecraft docking systems, and, more particularly, to a spacecraft grapple assembly that may be detachably coupled to a target object and a spacecraft docking system employing the grapple assembly.
Spacecraft are commonly equipped with a docking system that permits the spacecraft to be mechanically connected to an in-space object, such as a satellite, a space station, a second spacecraft, a module, and so on. The mechanical connection may permit the spacecraft's passengers to travel between the spacecraft and the object (e.g., a space station or spacecraft) or to perform maintenance on the object (e.g., a satellite or spacecraft). Docking may also enable spacecraft to exchange data and exhaustible supplies (e.g., power, water, and oxygen storages). In addition, the ability to form a mechanical connection between an appendage of the spacecraft and one or more modules (e.g., propulsion modules, habitat modules, electric power modules, storage modules, etc.) permits the assembly of in space structures.
To dock a spacecraft to a target object, the spacecraft is typically piloted to a desired location and docking procedures are commenced. In manual docking procedures, one or more passengers of the spacecraft may perform several steps to form a relatively stable connection between the spacecraft and the object. The docking systems supporting manual docking are generally complex and cumbersome, often including a retractable tunnel and a number of latching devices and seals. Automated docking systems requiring substantially less human guidance have been developed; however, such docking systems also tend to be complex and cumbersome. In addition, automated docking systems may require that the spacecraft is maneuvered to a precise location relative to the object before the docking process may commence. As a result, such processes may be relatively time consuming and, therefore, costly. Another limitation is that the automated docking system may use a semi-permanent docking means (e.g., electro-welding), which renders the undocking process more difficult. This may be especially undesirable when, for example, the docking and undocking process is continually repeated as during the assembly of a space structure.
Considering the foregoing, it should be appreciated that it is desirable to provide a spacecraft docking system that does not require precise maneuvering of a spacecraft relative to the target object and that produces a relatively stable spacecraft-to-object connection. Preferably, such a spacecraft docking system is relatively inexpensive to produce and amenable to automation. Ideally, the spacecraft docking system is scalable and utilizes a mechanical docking means that may easily and reliably disengage from the target object. Other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.
A spacecraft docking system configured to permit the docking of a spacecraft to a target object is provided. The docking system includes a grapple and docking interface, which is mounted on the target object. The grapple includes a body coupled to the spacecraft and at least one latching wing coupled to the body. The at least one latching wing is movable between a retracted position and an extended position, and configured to move into the extended position and latch onto the docking interface when the grapple is inserted therein.
A grapple assembly suitable for deploying on a spacecraft is also provided. The grapple assembly comprises a grapple, which includes: (i) an elongated body mounted through a wall of the spacecraft; and (ii) a plurality of latching wings pivotally coupled to the elongated body, which are movable between an extended position and a retracted position. The grapple also includes a latching wing retraction device, which is coupled to the body and configured to selectively move the plurality of latching wings into the retracted position. A grapple retraction device is coupled to the elongated body and configured to selectively retract the grapple such the plurality of latching wings move toward the wall of the spacecraft.
The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and:
The following detailed description of the invention is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding background of the invention or the following detailed description of the invention.
The docking interface may comprise any number of structures that cooperate to form a plurality of rail portions onto which grapple 16 may latch. For example, the docking interface may take the form of one or more elongated bodies having a generally helical or sinusoidal shape.
Wall 37 of spacecraft 10 includes an aperture 44 through which body 30 extends. To facilitate the mounting of grapple 16 through wall 37, a mounting structure 46 may be fixedly coupled (e.g., welded or soldered) thereto. In addition, a bearing assembly 48, which includes a plurality of rolling elements (e.g., ball bearings) 50, may be fixedly coupled to (e.g., bolted to) mounting structure 46 to facilitate the movement of grapple 16 with respect to wall 37.
As stated above, grapple assembly 14 includes a grapple retraction device 18, which is preferably disposed within spacecraft 10. Grapple retraction device 18 may be mounted to internal spacecraft structure 52 and coupled to distal end portion 34 of body 30 by way of a translatable shaft 54. In one option, the outer surface of shaft 54 is toothed, and grapple retraction device 18 includes at least one motor 56 having toothed gearings 58, which engage the teeth of shaft 54. Motor 56 selectively rotates toothed gearings 58, which causes toothed shaft 54, and thus grapple 16, to extend or retract with respect to wall 37 of spacecraft 10. In the illustrated exemplary embodiment, grapple retraction device 18 is equipped with two such motors 56, which engage opposite surface of shaft 54 to provide smooth operation and redundancy. This example notwithstanding, it should be appreciated that grapple retraction device 18 may assume any form suitable for extending and retracting grapple 16.
One or more biasing members may be disposed within body 30 to bias latching wings 36 toward their extended position. For example, a plurality of torsion springs 60 may be disposed around the pivot shafts of latching wings 36 and bias latching wings 36 toward their extended position. As a result, latching wings 36 will normally reside in the extended position until a force is exerted thereon sufficient to overcome the bias force supplied by torsion springs 60. This may occur as spacecraft 10 is maneuvered toward target object 12 when one or more latching wings 36 contact a cross-bar 24 of docking interface 22. Alternatively, latching wings 36 may be remotely retracted by a latching wing retraction device 62 disposed at least partially within body 30 of grapple 16. Wing retraction device 62 may include any device suitable for selectively retracting latching wings 36. In the exemplary embodiment shown in
Grapple controller 20 is operatively coupled to grapple retraction device 18 and wing retraction device 62. For example, grapple controller 20 may be coupled to motors 56 and 68 by way of electrical connections 72 and 74, respectively. Grapple controller 20 commands motors 56 to extend or retract grapple 16 and motor 68 to retract latching wings 36 as appropriate. Grapple controller 20 may include a user input that may be manually controlled by a passenger of spacecraft 10; however, grapple controller 20 preferably includes a processor incorporated into an automated docking system. Indeed, as explained in more below in conjunction with
It should be noted that grapple 16 may be inserted between any two rail portions of cross-bars 24. As a result, grapple 16 may dock with nearly any portion of docking interface 22 presented to grapple 16. The geometric dimensions of docking interface 22 may be varied as desired (e.g., the number and/or length of cross-bars 28 may be increased or decreased). By providing a docking interface that is relatively large (as compared to grapple 16), the spacecraft docking system may improve system tolerances and readily accommodate positional or navigational errors that may occur during the docking process. In addition, the distal end portion 32 (i.e., the nose) of grapple 16 may be tapered as indicated in
Grapple assembly 14 may readily undock from target object 12 by reversing the docking process. To commence the undocking procedure, grapple retraction device 18 first extends grapple 16 away from wall 37 of spacecraft 10 such that wings 36 move away from rail portions 28 of cross-bars 24 (
Advantageously, the above-described spacecraft docking system may be configured such that the docking process does not require the precise maneuvering of spacecraft 10 relative to target object 12. For example, docking interface 22 may be formed such that the distance between adjacent rail portions 28 is greater than the outer diameter of grapple 16 when latching wings 36 are in the retracted position, but less than the outer diameter of grapple 16 when wings 36 are in the expanded position (i.e., less than the wingspan of wings 36 in their extended position). Configuring the spacecraft docking system in the manner permits the insertion of grapple 16 between rail portions 28 of cross-bars 24 even when spacecraft 10 is not properly aligned with target object 12 (i.e., the path of travel of grapple 16 is not orthogonal to the plane of wall 37). To further illustrate this point,
It should thus be appreciated that there has been provided a spacecraft docking system that does not require precise maneuvering of a spacecraft relative to the docking object and is consequently amenable to an automated docking procedure. The spacecraft docking system is scalable, relatively inexpensive to produce, and produces a stable spacecraft-to-object connection. Furthermore, the spacecraft docking system employs a grapple assembly that may easily and reliably be disengaged from the docking object.
While at least one exemplary embodiment has been presented in the foregoing detailed description of the invention, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment of the invention. It being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the invention as set forth in the appended claims.
