Abstract:
An in-space spacecraft servicing system ( 10 ) includes a servicing spacecraft ( 22 ) and a propellant module ( 24 ). The servicing spacecraft includes a client servicing system ( 136 ), as well as navigation avionics ( 108 ) for independent flight operation and a servicing propellant tank ( 170 ). The propellant module moves the servicing module from an upper stage drop off location and releases it in proximity to a client spacecraft ( 16 ) for a servicing mission. It has a propellant tank ( 172 ) with capacity for multiple missions and is used to refill the servicing spacecraft&#39;s propellant tanks between missions. Either or both the servicing spacecraft and the propellant module may have navigation avionics. The servicing spacecraft also has a universal docking adaptor ( 70 ) for different client spacecraft, and can convert a client spacecraft from non-cooperative to cooperative.

Description:
RELATED PATENT APPLICATION 
     This application is a divisional of and claims priority from U.S. patent application Ser. No. 11/394,743 filed on Mar. 31, 2006. 
    
    
     TECHNICAL FIELD 
     The present invention relates generally to spacecraft and the in-space servicing thereof. More particularly, the present invention is related to the approaching, docking, coupling, and servicing of cooperative and non-cooperative spacecraft while in orbit. 
     BACKGROUND OF THE INVENTION 
     A significant portion of the spacecraft currently in orbit around the Earth are currently in need of servicing, or will be in the near future. The servicing needed may include propellant resupply, cleaning of solar panels, replacement or repair of various onboard equipment, or other servicing known in the art. These spacecraft are non-cooperative systems, which means that they are not designed to facilitate the servicing, docking or coupling with other space vehicles once on orbit. 
     There currently exists a technique of docking an extension spacecraft to a non-cooperative satellite for extending the life of that satellite. The extension spacecraft is designed specifically for that particular satellite, is permanently attached to that satellite, and has guidance, navigation, and controls for controlling all proximity operations with the satellite, as well as station keeping the resulting spacecraft-satellite combination. The extension spacecraft contains onboard propellant that is used by the extension spacecraft in performing all of the stated maneuvers. As such, the extension spacecraft concept is limited to one satellite and has limited use beyond this. The extension spacecraft is limited to controlling and adjusting the attitude and position of the spacecraft-satellite combination. Also, note that the satellite, the extension spacecraft, and the spacecraft-satellite combination remain in the satellites orbital position and are non-cooperative. 
     Another technique currently exists for launching into orbit a mothership vehicle that contains multiple operational service vehicles. Each of the operational service vehicles has a service module and a command module, which is attached and fixed to the service module. The service module has propellant, thrusters, and attitude control. The command module has target location/tracking/inspection sensors and robotic arms and grippers for performing service tasks. The operational service vehicles perform intricate tasks such as extending solar array panels or reorienting antennas. The stated vehicles are also limited in their use. The stated vehicles are limited in the amount of time they can operate away from the mothership, in their ability to replace spacecraft propellant and in their ability to provide a reliable or fixed connection with a spacecraft being repaired. 
     The above-stated extension spacecraft and service vehicles are also limited to single satellite service missions. Thus, for each spacecraft to be repaired a service vehicle must be launched into space. The associated costs, time, and efforts associated with each launch are substantial. 
     A significant portion of the satellites currently in orbit are spin-stabilized satellites. Docking with spinning satellites can be technically problematic. It is difficult to accurately position and adjust attitude angles and speed and angular velocity of servicing vehicles to align with the spin-stabilized satellites. A mismatch in alignment can cause a collision-like reaction. Thus, the spin-stabilized satellites are non-cooperative by their spinning nature alone. The remaining satellites are body stabilized satellites. Although easier to dock with, body stabilized satellites may also be non-cooperative. 
     Thus, there exists a need for a spacecraft that is capable of performing in-space service techniques, that overcomes the above-stated limitations, and that can be adjusted to safely and reliably dock with and service a variety of non-cooperative, cooperative, spin-stabilized, and body stabilized spacecraft. 
     SUMMARY OF THE INVENTION 
     One embodiment of the present invention provides an in-space servicing vehicle system that includes a servicing spacecraft and a propellant module. The servicing spacecraft includes a client servicing system for servicing a client spacecraft in space. The servicing spacecraft also includes navigation sensors and avionics for independent flight operation and propellant tanks for servicing. The propellant module moves the servicing spacecraft from an upper stage drop off location to a proximate location of the client spacecraft. The propellant module includes propellant tanks that contain propellant for multiple spacecraft-servicing missions. The servicing spacecraft separates from the propellant module and operatively approaches and docks with the client spacecraft. 
     Another embodiment of the present invention provides a similar in-space servicing vehicle system as stated in which the navigation control of the servicing spacecraft serves both the servicing spacecraft and the propellant module while the propulsive control of the propellant module serves both the propellant module and servicing spacecraft. 
     Another embodiment of the present invention provides a similar in-space servicing vehicle system as stated in which the navigation control and propulsive control of the servicing spacecraft serve both the servicing spacecraft and propellant module. 
     Still another embodiment of the present invention also provides a similar in-space servicing vehicle system as stated where the servicing spacecraft has a universal docking adaptor that couples to and converts the client spacecraft from non-cooperative to cooperative. 
     The embodiments of the present invention provide several advantages. One such advantage is the provision of an in-space servicing vehicle that is capable of performing multiple in-space missions and in doing so has the versatility and ability to accommodate and service multiple spacecraft using a minimal number of distinct mechanisms. 
     Furthermore, another advantage provided by an embodiment of the present invention is the provision of an in-space servicing vehicle that is capable of adjusting itself to the dynamic characteristics of servicing non-cooperative, cooperative, spin-stabilized, and body stabilized spacecraft. 
     Yet another advantage provided by an embodiment of the present invention is the provision of an in-space servicing vehicle that is capable of approaching, docking, and coupling to a client spacecraft without the manipulation or reconfiguration of the client spacecraft. Thus, the stated embodiment avoids the altering of the dynamic properties of the client spacecraft, minimizes disturbance to the client spacecraft, and minimizes the requirement for a realignment procedure at the completion of servicing the client spacecraft. 
     Still another advantage provided by an embodiment of the present invention, is the ability to achieve a soft, non-impact, sturdy, and reliable in-space connection to a variety of client spacecraft for servicing thereof. 
     The present invention itself, together with further objects and attendant advantages, will be best understood by reference to the following detailed description, taken in conjunction with the accompanying drawing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a multi-mission diagram incorporating an in-space servicing vehicle system in accordance with an embodiment of the present invention; 
         FIG. 2  is a single mission diagram illustrating communication between a servicing spacecraft, a propellant module, and a remote ground tracking and control system in accordance with an embodiment of the present invention; 
         FIG. 3A  is an external perspective view of the in-space servicing vehicle system of  FIG. 1 ; 
         FIG. 3B  is a perspective view of the in-space servicing vehicle system of  FIG. 1  illustrating internal propellant tanks thereof; 
         FIG. 4  is a perspective view of a propellant module in accordance with an embodiment of the present invention; 
         FIG. 5A  is a block diagrammatic view of the in-space servicing vehicle system of  FIG. 1 ; 
         FIG. 5B  is the block diagrammatic view of  FIG. 5A  continued; 
         FIG. 6  is a perspective view of a servicing spacecraft in accordance with an embodiment of the present invention; 
         FIG. 7A  is a perspective view of an adjustable spacecraft coupling adaptor in a non-deployed orientation and in accordance with an embodiment of the present invention; 
         FIG. 7B  is a perspective view of an adjustable spacecraft coupling adaptor in a fully deployed orientation and in accordance with an embodiment of the present invention; 
         FIG. 8  is a side perspective view of a servicing spacecraft with a telescoping and rotating boom in relation to a client spacecraft and in accordance with an embodiment of the present invention; 
         FIG. 9  is a perspective approaching and coupling diagram of universal docking adaptor coupling to a client spacecraft in accordance with another embodiment of the present invention; 
         FIG. 10  is a side perspective view of a dual servicing coupling adaptor system in accordance with another embodiment of the present invention; 
         FIG. 11  is a close-up perspective view of a portion of the universal docking adaptor of  FIG. 9 ; 
         FIG. 12  is a close-up perspective view of a propellant transfer coupling and transfer servicing system in accordance with an embodiment of the present invention; 
         FIG. 13  is a close-up view of a propellant transfer system self-aligning tool in accordance with an embodiment of the present invention; 
         FIG. 14  is a close-up perspective view of a client spacecraft propellant transfer coupling assembly; and 
         FIG. 15  is a close-up view of a propellant transfer line-bracing tool in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     In each of the following Figures, the same reference numerals are used to refer to the same components. The present invention may be applied to various in-space servicing applications. The present invention may be used to service non-cooperative, cooperative, spin-stabilized, and body stabilized spacecraft, as well as other spacecraft known in the art. The present invention may also be used to perform various servicing tasks. 
     In the following description, various operating parameters and components are described for one constructed embodiment. These specific parameters and components are included as examples and are not meant to be limiting. 
     In the following description the terms “servicing” and “servicing tasks” may refer to any task performed by a spacecraft to clean, adjust, replace, repair, update, salvage, recommission, decommission, reposition, reorient, or align another spacecraft or components or systems thereof or to perform some other task on another spacecraft known in the art. Some example service tasks are the resupplying of spacecraft propellant, the cleaning, adjusting, replacement, and deployment assistance of solar arrays and panels, the updating and repairing of onboard electronics and software, the delivery of batteries, the delivery of attitude control devices, spacecraft inspection, and the orbital relocation of a spacecraft. 
     Also, in the following description the term “servicing mission” may refer to one or more servicing tasks performed on a particular spacecraft. The term “spacecraft-servicing mission” refers to a planned group of servicing tasks, which may be scheduled, and that are performed upon a particular spacecraft by a servicing vehicle prior to separation of the servicing vehicle from that spacecraft. As an example, a servicing vehicle may service multiple spacecraft and travel to each spacecraft between performing respective spacecraft-servicing missions. 
     Referring now to  FIG. 1 , a multi-mission diagram incorporating one or more in-space servicing vehicle systems  10  (only one is shown) in accordance with an embodiment of the present invention is shown. The in-space system  10  is capable of performing multiple spacecraft-servicing missions. The in-space system  10  is launched from earth  12  via a launch vehicle (not shown), such as a rocket, to a low earth orbit or to a geosynchronous orbit. The in-space system may be utilized for other types of missions as well, such as servicing spacecraft in sun synchronous or polar orbit. In this example, the in-space system  10  is shown in a geosynchronous orbit  14 . The launch vehicle may consist of multiple stages and include one or more vehicles. For example, the launch vehicle may include an orbit transitory vehicle, which transfers the in-space system  10  from a low earth orbit to a geosynchronous orbit. The launch vehicle or the in-space system  10  itself may have the capabilities to transfer the in-space system  10  from a low earth orbit to a geosynchronous orbit. The launch of the in-space system  10  and the transition from a low earth orbit to a geosynchronous orbit is generally indicated by numerical designator  1 . 
     In the diagram provided, three client spacecrafts  16   18 , and  20 , which are in the form of satellites, are shown. The in-space system  10  travels to each of the satellites for servicing thereof. Once in a geosynchronous orbit the in-space system  10  begins operations, as generally indicated by numerical designator  2 . The in-space system  10  moves to a proximate location of a first client spacecraft, such as the proximate location  21  of the client satellite  16 , for preparation and proximate servicing of that client spacecraft, as generally indicated by numerical designator  3 . The in-space system  10  may travel along the elliptical orbit  14  of the client spacecrafts  16 ,  18 , and  20 , as shown, or in some other trajectory, one such trajectory  23  being shown. 
     The in-space system  10  includes a servicing spacecraft  22  and a propellant module  24 . The servicing spacecraft  22  separates from the propellant module  24  and travels to, approaches, docks, and couples with the client spacecraft. This is generally indicated by numerical designator  4 . 
     Once docked, the servicing spacecraft  22  performs servicing tasks associated with the spacecraft-servicing mission designated for the first client spacecraft, as generally indicated by numerical designator  5 . Upon completion of the first spacecraft-servicing mission, the servicing spacecraft  22  separates from the first client spacecraft and returns to the propellant module  24 , as represented by numerical designator  6 . The servicing spacecraft  22  when coupled to the propellant module  24  may prepare for the next spacecraft-servicing mission. The servicing spacecraft  22  may refill its propellant tanks or perform some other tasks in preparation for the next servicing mission. After returning to the propellant module  24 , the servicing spacecraft  22  docks and couples with the propellant module  24 . The in-space system  10  then travels to the next client spacecraft to be serviced, such as the spacecraft  18 . This is generally indicated by numerical designator  7 . Trajectory paths  26  between spacecraft  16 ,  18 , and  20  are shown. 
     The above-stated process, as represented by numerical designators  1 - 7 , is for example purposes only. The process may be altered and steps therein may be performed simultaneously or in a different order depending upon the application. The circles  28  represent locations of the in-space system  10  during servicing of the spacecraft  16 ,  18 , and  20 . 
     Referring now to  FIG. 2 , a single mission diagram illustrating communication between the servicing spacecraft  22 , the propellant module  24 , and a remote ground tracking and control system  40  in accordance with an embodiment of the present invention is shown. The in-space system  10  may operate autonomously or may be remotely controlled via the ground station  40 . The in-space system  10  is capable of communicating with the ground station  40 , as represented by signal line  42 . The servicing spacecraft  22  and/or the propellant module  24  may have communication electronics for communicating with the ground station  40 . In the example embodiment shown, the servicing spacecraft  22  has an omni-directional antenna  44  and is capable of communicating with the propellant module  24 , but not with the ground station  40 . This is indicated by communication signal line  46 . The propellant module  24  has a high gain antenna  48  for communicating with the ground station  40 , as is indicated by communication signal line  49 . In another embodiment the servicing spacecraft  22  communicates directly with the ground station  40 , as indicated by communication signal line  42 . 
     The ground station  40  includes communication antennas  50 , signal processors  52 , a guidance and navigation controller  54 , and may include a remote controller  56 . The guidance and navigation controller  54  contains systems for monitoring, tracking, and controlling the attitude, position, location, orbit and operation of one or more spacecraft including the in-space system  10 . The remote controller  56  provides the systems and controls to remotely and manually adjust, alter, or control the attitude, position, location, orbit, and operation of one or more spacecraft including the in-space system  10 . The remote controller  56  may include items, such as a remote cockpit  58 , pilot input devices  60 , hand controls  62 , inspection devices  64 , displays  66 , engine controls  68 , and other controls known in the art. 
     Referring now to  FIGS. 3A ,  3 B and  4 , perspective views of the in-space system  10  and a perspective view of the propellant module  24  are shown in accordance with an embodiment of the present invention.  FIG. 3A  provides an external perspective view, whereas  FIG. 3B  provides an internal perspective view. The servicing spacecraft  22  is coupled to the propellant module  24  via a universal docking adaptor  70  and a corresponding docking and coupling interface  72 . The universal docking adaptor  70  is adjustable and reconfigurable to couple to various different spacecraft and to the docking interface  72 . This is described in greater detail below. 
     The servicing spacecraft  22  includes a main body or servicing utility unit  74  and a solar array  76  which in this embodiment encircles at least a portion of the servicing unit  74 . Alternate embodiments may include alternate solar array configurations or other means of power generation. The universal docking adaptor  70  is coupled to the servicing unit  74  and extends therefrom. 
     In a preferred embodiment, the propellant module  24  includes a main body or propellant utility box  78  from which solar arrays  80  and the main high gain antenna  48  are coupled and extend therefrom. Alternate embodiments may include alternate solar array configurations and antenna configurations. The docking interface  72  is attached to a front side  82  of the utility box  78 . 
     The universal docking adaptor  70  has multiple adjustable and reconfigurable outward swinging arms  84  and coupling members  86 . The coupling members  86  extend within channels  88  in the docking interface  72  and attach to the docking interface  72 , as shown. Propellant is transferred from the propellant module  24  through the docking interface  72  and universal docking adaptor  70  to the servicing spacecraft  22 . Propellant lines (not shown) may be connected between the servicing spacecraft  22  and the propellant module  24  via space rated quick disconnect devices known in the art. 
     In one embodiment, while docked with the propellant module  24 , the servicing spacecraft  22  is in a power save mode and the propellant module provides the propulsion and navigation to transfer from client-to-client. In another embodiment, the servicing spacecraft  22  provides the navigation control for the in-space vehicle  10  while the propellant module  24  provides the propulsion. In still another embodiment, the servicing spacecraft  22  provides both the navigation control and propulsion for the in-space vehicle  10 . With the servicing spacecraft  22  providing navigation control, the propellant module may be used solely as a set of propellant tanks, which the servicing module moves from client-to-client. The servicing spacecraft  22  may fill its own propellant tanks from propellant on the propellant module  24 . When the servicing spacecraft  22  separates from the propellant module  24  to service a client spacecraft, the propellant module may be placed in some stable spinning orientation and left to drift in a predictable manner until the servicing spacecraft  22  returns. 
     Referring now also to  FIGS. 5A-B , a block diagrammatic view of the in-space system  10  is shown. The servicing spacecraft  22  and the propellant module  24  may have a number of components including communication systems  100 ,  102 , command and data handling systems  108 ,  110 , guidance navigation and control systems  151 ,  153 , propulsion systems  116 ,  118 , servicing spacecraft resupply systems  120 ,  122 , client servicing system  136  (servicing spacecraft only), electrical supply systems  124 ,  126 , docking systems  128 ,  130 , thermal control systems  132 ,  134 , and other space related systems housed in their utility units/boxes  74 ,  78 . The stated systems may include sensors, cameras, robotic systems, tools, and various other systems, components, and tools for performing various tasks associated therewith. The client servicing system  136  of the servicing spacecraft  22  may include a number of components, such as the propellant sensors  140 , the robotic arm  142 , propellant couplers  182 , and the servicing tools  144 . 
     Note that many of the systems and devices of the propellant module  24  are shown with dashed boxes to suggest that they may or may not be included. An example of this is when the propellant module  24  is being used solely as a set of propellant tanks. Although none of the systems and devices of the servicing spacecraft  22  are shown with dashed boxes, this does not suggest that all of the shown systems and devices of the servicing spacecraft  22  are required or used. 
     Each of the communication systems  100  and  102  may include main controllers  104  and  106 , encoder/decoders  105 ,  107 , memory devices  222 ,  224 , as well as communication antennas, transmitters/receivers, and other communication equipment known in the art. The communication systems  100  and  102  may be in communication with each other, with a ground-based system, and/or with other spacecraft. 
     The main controllers  104  and  106  may be microprocessor based such as a computer having a central processing unit, memory (RAM and/or ROM), and associated input and output buses. The main controllers  104  and  106  may be application-specific integrated circuits or may be formed of other logic devices known in the art. The main controllers  104  and  106  may be portions of a central vehicle main control unit, may be control circuits having power supplies, may be combined into a single integrated controller, or may be stand-alone controllers as shown. 
     In a preferred embodiment, each spacecraft subsystem on the servicing spacecraft  22  and propellant module  24  is a separate entity. They communicate with each other, but operate independently. Alternate embodiments of the servicing spacecraft  22  and/or propellant module  24  could combine any subsystem with a combination of one or some or all of the other spacecraft subsystems. For example, the command and data handling systems  108  and  110  and the propulsion systems  116  and  118  may include the communication systems  100  and  102  and any other command or flight operation systems and devices known in the art. The command and data handling systems  108  and  110  and the propulsion systems  116  and  118  may include equipment typically found on a spacecraft with regards to flight operations, navigation, guidance, communication, etc. 
     The guidance navigation and control systems  151  and  153  may include star trackers/sun sensors  150 ,  152 , IMUs  154 ,  156 , and reaction wheels  158 ,  160 . 
     The propulsion systems  116  and  118  may include main thrusters  162 ,  164 , reaction control systems  112 ,  114 , onboard mono propellant tanks  170 ,  172 , helium or other pressurant tanks  174 ,  176  (shown in  FIGS. 4 and 6 ) and/or fuel and oxidizer tanks  178 ,  180 , and other propellant related tanks known in the art. The pressurant tanks  174 ,  176  may be used to pressurize the propellant tanks  170 ,  172   178 ,  180 . The propulsion systems  116  and  118  provide propellant for flight by the servicing spacecraft  22  and/or the propellant module  24 . The propulsion systems  116  and  118  supply propellant to the thrusters  162  and  164 , which are controlled by the command and data handling systems  108  and  110  and the main controllers  104  and  106 . The propellant tanks  170 ,  172 ,  178 ,  180  are pressurized and thus propellant contained therein is transferred through the use of valves (not shown). 
     In a preferred embodiment, the propellant tanks  172  and  180 , on the propellant module  24 , act as storage tanks and contain enough propellant for both units to perform multiple spacecraft-servicing missions. The propellant tanks  172  and  180  contain enough propellant to allow the servicing spacecraft  22  to perform multiple spacecraft-servicing missions, for the propellant module  24  to travel between multiple spacecraft, and/or for propellant resupply of multiple client spacecraft. In another embodiment, there could be separate sets of propellant tanks on the propellant module  24 , one set for storing client propellant and one set for storing propellant for the propellant module  24  and/or the servicing spacecraft  22  to use to travel between multiple client spacecraft. The propellant tanks  170  and  178  on the servicing spacecraft  22  contain enough propellant to perform one or more spacecraft-servicing missions. 
     The servicing spacecraft resupply systems  120  and  122  and the client servicing system  136  may include the main controllers  104  and  106  that control the transfer of propellant from the propellant module  24  to the servicing spacecraft  22  and/or from the servicing spacecraft  22  to a client spacecraft being serviced. Propellant couplers in the form of quick disconnects  184  and  186  within or on the servicing spacecraft  22  and the propellant module  24  are used to couple the propellant supply and return lines (not shown). Propellant may be transferred from propellant tanks through propellant lines on the propellant module  24  to the servicing spacecraft  22 , either through docking ports in the universal docking adaptor  70  and the docking interface  72  between the propellant module  24  and servicing spacecraft  22 , and/or through a robotic arm for coupling propellant lines to propellant tanks on the servicing spacecraft  22 . Propellant may also be transferred from the propellant tanks and propellant lines on the servicing spacecraft  22  to propellant tanks located on a client spacecraft being serviced. Example of client spacecraft propellant lines and couplings and techniques for attaching thereto are shown in and described with respect to FIGS.  9  and  12 - 13 . 
     The electrical supply systems  124  and  126  may include generator/alternators  190 ,  192 , batteries  194 ,  196 , solar arrays  198 ,  200 , power busses  206 ,  208 , power control equipment  226 ,  228 , and various electrical connections, lines, and couplers between the utility unit/boxes  74  and  78  and any spacecraft docked therewith, which are designated as spacecraft electrical couplers  202 ,  204 . Upon docking of the servicing spacecraft  22  to the propellant module  24 , electrical connections may be made between the electrical supply system  124  and the electrical supply system  126  using the electrical quick disconnects  187  and  185 . Electrical power may be supplied between power buses  206 ,  208  and/or the batteries  194  and  196 . The electrical supply systems may include or be connected to the main controllers  104  and  106  which monitor and adjust the supply of electrical power. 
     The docking systems  128  and  130  may include docking sensors  210  and  212 . The docking sensors  210  and  212  may be used to assure that the servicing spacecraft  22 , the propellant module  24 , and various client spacecraft are docked and coupled to each other properly, especially prior to any propellant transfer. The docking sensors  210  and  212  may be of various types and styles. The docking sensors  210  and  212  may be in the form of contact sensors, infrared sensors, resistive sensors, cameras, or other similar sensors known in the art. 
     The servicing spacecraft docking system  128  may contain one or more docking adapters  209  and coupling members  213  used to dock the servicing spacecraft  22  to the propellant module  24  or to various client spacecraft. The docking adaptor  209  may include the universal docking adaptors  70  and  300 , which are described above and also further below. The coupling members  213  may include the coupling members  86 ,  320 , and  370  described above and below. The propellant module docking system  130  may include coupling channels/locks  215 , such as the channels  88  described above. The docking system  130  also may include a docking interface  217 , similar to the above-described docking interface  72  which couples to the universal docking adaptor  70 . 
     The thermal control systems  132  and  134  provide the utility unit/boxes  74  and  78  with the systems to control the temperatures of the subsystem hardware and propellant system elements located within the utility unit/boxes  74  and  78 . The thermal control systems  132  and  134  as embodied may include cold plates  214 ,  216 , and heaters, thermostats and blankets  219 ,  221 , which may be coupled to the communication systems  100  and  102 , the command and data handling systems  108  and  110 , and the electrical power supply systems  124  and  126 . The cold plates  214  and  216  are coupled to heat rejection systems  218  and  220  as typically found and utilized in the art. 
     The client servicing system  136  may include the main controller  104  and any other devices, systems, and tools in the above-stated systems and others known in the art. The client servicing system  136  is used in general to perform servicing tasks on client spacecraft, but may be used to perform servicing tasks on the servicing spacecraft  22  or the propellant module  24 . The servicing spacecraft resupply system  122  in general is not used to perform servicing tasks other than to resupply propellant to the servicing spacecraft  22 , but may be used to perform servicing tasks on the servicing spacecraft  22  or the propellant module  24 . 
     The utility unit/boxes  74  and  78  and the above-identified systems contained therein may include additional housings (not shown) for other standard bus box sub systems that are normally found on a spacecraft. The utility unit/boxes  74  and  78  may include memory or data storage devices  222 ,  224 , power control boxes and equipment  226 ,  228 , encoders/decoders  105 ,  107  and other flight equipment, some of which may be part of one or more of the above-stated systems, as shown. The utility unit/boxes  74  and  78  include standard satellite bus functions, such as communication, power generation and distribution, and command and data handling. 
     Referring now to  FIGS. 6 ,  7 A and  7 B, a perspective view of the servicing spacecraft  22  incorporating the universal docking adaptor  70  and a perspective close-up view of the universal docking adaptor  70  are shown in accordance with an embodiment of the present invention.  FIG. 7A  shows the universal docking adaptor  70  non-deployed and  FIG. 7B  shows the universal docking adaptor  70  fully deployed. The servicing vehicle  22 , as shown, includes the universal docking adaptor  70 , the robotic arm  142 , and the thruster probe  240 . Note that the servicing spacecraft  22  is typically smaller in size than the client spacecraft it services, and can be configured and shaped to approach various client spacecraft while minimizing interference and without causing damage to the client spacecraft. 
     In  FIG. 6 , the universal docking adaptor  70  is coupled to a front end  242  of the servicing spacecraft  22  and includes the outward swinging arms  84  and the coupling members  86 . The arms  84  swivel via pins  244  and linkages  246 , which couple adjacent arms  84 . The arms  84  are supported by support elements  248 , which are coupled to a base  250 . The coupling members  86  extend axially from the arm ends  252  of each arm  84  and are used to couple to the docking interface  72  and to other spacecraft. An adaptor motor  254  is coupled within the base  250 , may be activated by the main controller  104 , and is used to adjust the orientations of the arms  84 . Additional motors and linkages may be used to allow the coupling members  86  to be rotated, retracted, or placed in different orientations. The configuration provided allows the arms  84  to be evenly swiveled outward in a uniform manner and at a multiple number of increments. This allows the universal docking adaptor  70  to couple to many client spacecraft having different configurations. For example, the universal docking adaptor  70  may be adjusted to align with, contact, and couple to different sized launch adaptor rings of different client spacecraft. 
     As shown in  FIGS. 7A and 7B , the coupling members  86  are shown swiveled radially outwardly to different circumferential positions for coupling to different diameter adaptor rings of client spacecraft, as represented by dashed circles  256 . The configuration of the arms  84  and the coupling members  86  is shown for example purposes only; various other configurations may be utilized. 
     The coupling members  86  may be of various types, styles, and may be in various configurations. In the example embodiment shown, each of the coupling members  86  has a main member  260  and an engagement member  262  attached thereto. For example, the engagement member can have a “Y”-shape for engaging an adaptor ring of a client spacecraft. The coupling members  86  may have pads, dampening materials attached, or other items to provide a soft contact of the servicing spacecraft  22  and client spacecraft. Sample pads  264  are shown with respect to the embodiment of  FIG. 10 . The coupling members  86  may also have inflatable airbags  266  (only one is shown) or the like that extend therefrom, as shown in  FIG. 11 , which dampen the interaction between the servicing spacecraft  22  and a client spacecraft. 
     The thruster probe  240  is aligned with the center axis and used in the approach and alignment of the servicing vehicle  22  with a client spacecraft. The thruster probe  240  extends from the center  268  of the base  250  and is aligned with a thruster of a client spacecraft. Multiple thruster probe designs known in the art can be utilized for attachment to the thruster cone of the client satellite. For example, the tip  270  of the thruster probe  240  can have an expandable element  272 , which expands in the client spacecraft thruster. In a preferred embodiment, during the approach process and with respect to a spin-stabilized spacecraft, the entire servicing vehicle  22  is spun through propulsion or other means to rotate at the same rate and about the same axis as the client spacecraft. The base  250  is projected towards the spinning spacecraft to allow for insertion of the probe  240  into the respective thruster. The base  250  is projected, via the adaptor motor  254 , the telescoping boom motor  274 , and the telescoping boom  276 , which is shown in  FIGS. 8 and 10 . The telescoping boom  276  is adaptable to a specific depth of a client spacecraft being serviced. In an alternate embodiment, only the base  250  is rotated, at the same rate and about the same axis as the client, and projected, via the adaptor motor  254 , the telescoping boom motor  274 , and the telescoping boom  276 . In this case the main body  74  of the servicing spacecraft  22  does not rotate with respect to the rotating client. 
     As shown in  FIG. 12 , a robotic arm  142  may be used on the servicing spacecraft  22  to perform various servicing tasks. Tools may be coupled to the end of the robotic arm  142  to accommodate for such tasks. Although a single robotic arm is shown, any number of which may be incorporated. Some tools are shown in  FIGS. 5 ,  12 ,  13 , and  15 . 
     Referring now to  FIG. 8 , a side perspective view of a servicing spacecraft  22  in relation to a client spacecraft  280  in accordance with an embodiment of the present invention is shown. In the embodiment shown, the servicing spacecraft  22  is configured with the telescoping and rotating boom  276 , which extends within a cylindrical solar array  282  of a client spacecraft  280 . The extension direction is depicted by arrow  284 . The telescoping boom  276  may have telescoping sections (not shown), may turn outward via a screw (not shown), or may telescope outward using some other technique known in the art. 
     As the boom  276  is extended the arms  84  of the docking adaptor are swiveled outward and the coupling members  86  are extended in a forward direction to align with the rim  286  of the launch adaptor ring  288 . The thruster probe  240  is inserted into the thruster  290  and the tip  272  is expanded to hold the probe  240  in position relative to the client spacecraft  280 . After insertion of the probe  240 , the coupling members  86  are projected forward to mate with the launch ring  288 . 
     Referring now to  FIG. 9 , a perspective diagram of a universal docking adaptor  300  of a servicing spacecraft is shown coupling to a client spacecraft  302  in accordance with another embodiment of the present invention. In the diagram, a main support cylinder portion  304  of a telescoping boom  306  of a servicing spacecraft, similar to the servicing spacecraft  22  above-described, is shown. The telescoping boom  306  does not have a base on the forward end  308 , as with the telescoping boom  276  in  FIG. 8 . The main support cylinder  304  has reinforcement structure in the form of ribs  310  that extend longitudinally at predetermined and regular increments along the cylindrical side  312  of the main support cylinder  304 . The ribs  310  have hinges or joints  314 , which allow segments  316  thereof to fold and form arms  318 . Coupling members  320 , similar to the coupling members  86 , may be attached to one or more of the segments  316 . The coupling members  320  are used to couple to the rim  322  of the launch adaptor ring  324  of the client spacecraft  302 . The coupling members  320  when coupled across multiple segments  316  are able to be extended laterally outward to couple and press against the interior surface  326  of the launch adaptor ring  324 . 
     In the diagram provided the servicing spacecraft approaches the client spacecraft  302 . The telescoping boom  306  and thus the main support cylinder  304  is extended toward the thruster of the client spacecraft  302 . A thruster probe  328 , similar to the thruster probe  240  in  FIG. 8 , is extended from the main support cylinder  304  and into the thruster  330  of the client spacecraft. The arms  318  are extended outward, via the joints  314  and internal motors (not shown). The coupling members  320  are then aligned and brought into contact with the rim  322 . 
     The client spacecraft  302  shown has a propellant transfer coupling assembly  340  with a stabilizer thruster  342  attached thereto. A robotic arm  344  may extend from the servicing spacecraft and couple to the propellant transfer coupling assembly  340 . This is further shown and described with respect to the embodiments of  FIGS. 12-15 . 
     Referring now to  FIG. 10 , a side perspective view of a dual-function servicing coupling adaptor system  350  of a servicing spacecraft  351  in accordance with another embodiment of the present invention is shown. The dual-function adaptor system  350  includes a first adaptor  352  and a second adaptor  354 . The dashed line  353  shows the breaking point between the first adaptor  352  and the second adaptor  354 . The first adaptor  352  includes cooperative coupling mechanisms  362  which interface with the cooperative coupling mechanisms  364  on the second adaptor  354 . The first adaptor also includes non-cooperative interface mechanisms for attaching to the client satellite. These mechanisms include coupling members  370  and pads  264 . The second adaptor  354  is coupled to the end  356  of a telescoping boom  358 . For coupling the two spacecraft together, the first adaptor  352  is coupled to the second adaptor  354 . The first adaptor  352  is delivered to the client spacecraft  360  by the servicing spacecraft  351  and is permanently attached to and converts the client spacecraft  360  from a non-cooperative spacecraft (lacking a usable adaptor) to a cooperative spacecraft (having a usable adaptor). The second adaptor  354  remains on the telescoping boom  358  and separates from the first adaptor  352  upon servicing the client spacecraft  360 . 
     In one embodiment the first adaptor  352  has a cooperative coupling mechanism  362  which is fixed in the frame of reference of the client spacecraft  360 . In an alternate embodiment, the first adaptor  352  has a non-spinning inner section and cooperative coupling mechanisms  362 . As the client spacecraft  360  is spinning, the inner section and cooperative coupling mechanism  362  may in effect be rotated in an opposite direction to compensate for the rotation of the client spacecraft  360 . Furthermore, the rotation of the inner section and cooperative coupling mechanism  362  can be fine-tuned by commands from either the client spacecraft or the servicing spacecraft. This equal and opposite rotation of the inner section and cooperative coupling mechanism  362  in effect causes the inner section and cooperative coupling mechanism  362  to be stationary. As an alternative, bearings (not shown) or the like may be coupled between the inner section and cooperative coupling mechanism  362  and the client spacecraft  360  and/or the inner section and cooperative coupling mechanism  362  may be weighted or balanced such that it remains stationary. The non-rotation of the inner section and cooperative coupling mechanism  362  allow the first adaptor  352  to be easily approached and docked to in the future. The cooperative coupling mechanisms  362  and  364  may include docking couplers, propellant transfer couplers, and electrical couplers, as well as other couplers known in the art. 
     The first adaptor  352 , as shown, illustrates another example of coupling members that may be used with a universal docking adaptor of the servicing spacecraft, such as that described above. In this embodiment, the non-cooperative interface of the first adaptor  352  includes the coupling members  370 . The coupling members  370  extend laterally outward from the base  372 . The coupling members  370  have the pads  264 , which are pressed against the inner wall  376  of the launch adaptor ring  378 . 
     Referring now to  FIG. 11 , a close-up perspective view of a portion of the universal docking adaptor  300  and main support structure  304  of  FIG. 9  is shown. The main support structure  304  has the reinforcement ribs  310 , which slide in slots  380 . The ribs  310  are able to extend laterally outward and fold via the joints  314 . The coupling members  320  are shown as being attached to the segments  382  of the ribs  310 . Airbags  384  may be deployed from or attached to the main support structure  304 , the ribs  310 , and/or the coupling members  320 . 
     The airbags  384  may deploy perpendicular to the main support structure  304 . The airbags  384  may be inflated gradually, until they touch the interior surface of a client spacecraft element, such as the launch adaptor rings  324  and  378 . The airbags  384  serve as dampening cushions to reduce the mismatch impact between the speed/attitude of the main support structure  304  and the speed/attitude of the client spacecraft to be serviced. 
     Referring now to  FIGS. 12 and 13 , close-up perspective views show a propellant transfer coupling and transfer servicing system  390  to be detached and attached to a client spacecraft  392  in accordance with an embodiment of the present invention. The propellant transfer system  390  shown includes a robotic arm  394  having multiple sections  396  that pivot relative to each other via motors  398  coupled therebetween. The robotic arm  394  has a tool  400  equipped with a self-aligning adaptor  404 , which is coupled to a propellant transfer coupling end  402  of the robotic arm  394 . The self-aligning adaptor  404  is “U”-shaped and has an open width between fork members  404  that is approximately equal to the width of a client spacecraft propellant transfer coupling assembly  406  of the client spacecraft  392 . The fork members  404  slide over the outer surfaces  408  of an outer bracket  410  of the client propellant transfer coupling assembly  406 . This guides the propellant transfer coupling end  402  to align and mate with one of the corresponding client propellant transfer couplings  412  extending from the bracket  410 . Of course, various other propellant transfer coupling configurations and arrangements may be utilized. 
     Referring now to  FIG. 14 , a close-up perspective view of one embodiment of a client spacecraft propellant transfer coupling assembly  420  is shown. This client propellant transfer coupling assembly  420  includes three propellant transfer couplings  422 , which are coupled to and extend from an outer bracket  424 . The outer bracket  424  is coupled to a support beam  426  that extends out from the client spacecraft  428 . Propellant lines  430  are coupled to the propellant transfer couplings  422 , which extend through the support beam  426  and to propellant tanks (not shown) within the client spacecraft. A stabilizing thruster  432  is also located in the vicinity of the support beam  426  and to the propellant lines  430 . The stabilizing thruster  432  is used to stabilize the client spacecraft during various operations. 
     Referring now to  FIG. 15 , a close-up view of a propellant transfer line-bracing tool  448  in accordance with an embodiment of the present invention is shown. The propellant line-bracing tool  448  has a “jaw” like design and includes a pair of side brackets  442  that are coupled on a first end  444  via a hinge  446 . The brackets  442  are moved into position to extend along side one of the propellant transfer couplings in the client propellant transfer assembly, such as the propellant transfer couplings  422  in  FIG. 14 , and are rotated inward to grasp a propellant transfer coupling. A single client propellant transfer coupling  450  is shown. As the brackets  442  are rotated inward its ends are placed between the propellant transfer coupling  450  and the outer bracket  406 . Each of the side brackets  442  has an inner edge  452  with a semi-circular cutout portion  454 . As the brackets  442  are brought together the semi-circular portions  454  (only one is shown) form a circular opening which encircles a client propellant transfer coupling. The diameter of the opening provides a tight fit on the diameter of the propellant transfer coupling  450 , thereby preventing the line-bracing tool  448  from being pushed away from the propellant transfer coupling  450  during the propellant transfer process. During propellant transfer the servicing spacecraft propellant transfer system, such as the robotic arm propellant transfer system  390  shown in  FIG. 12 , may be subject to high back-pressures. The propellant transfer line bracing tool  448  helps withstand these back pressures and prevents the propellant transfer system from detaching or becoming dislodged or separated from the client propellant transfer assembly. 
     The present invention provides a servicing vehicle that is specialized to meet various client spacecraft requirements. The present invention also provides a technique of converting a non-cooperative vehicle into a fully cooperative vehicle and is compatible with spin stabilized and body stabilized spacecraft. The universal docking adaptors of the present invention are lightweight and reconfigurable to accommodate different spacecraft. 
     While the invention has been described in connection with one or more embodiments, it is to be understood that the specific mechanisms and techniques which have been described are merely illustrative of the principles of the invention, numerous modifications may be made to the methods and apparatus described without departing from the spirit and scope of the invention as defined by the appended claims.