Patent Publication Number: US-11643227-B2

Title: In-orbit spacecraft servicing through umbilical connectors

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a nonprovisional patent application of and claims the benefit of U.S. Provisional Patent Application No. 62/904,715 filed Sep. 24, 2019 and titled “In-orbit Service to a Spacecraft Through Its External Connectors,” the disclosure of which is hereby incorporated herein by reference in entirety. 
    
    
     FIELD 
     The disclosure relates generally to systems and methods of use to provide servicing of a space object, and more specifically to systems and methods of use to provide in-orbit servicing of a spacecraft through the umbilical connectors of the spacecraft. 
     BACKGROUND 
     Throughout ground and launch operations, the connection with internal systems onboard a spacecraft is done through electrical connection interfaces on the outer surface of the spacecraft. For example, testing of a subsystem on the ground, while covered by outer protection layers, may be achieved through a dedicated connector on the outer panel through which the status of the subsystem may be checked and test protocols may be run. Another example are the connectors, known as “umbilical connectors,” through which the spacecraft is tested, monitored and controlled while on the launcher during launch operations, and are separated from its mating part on the launcher side during the separation of the spacecraft from the launcher. 
     Conventionally, spacecraft are not intended to be communicated with through these external connectors after launch, and all communication thereafter is done through telecommunication from the ground (by Radio Frequency (RF) transmissions with the ground, e.g. in C, X, Ku, S bands). For example, geostationary satellites for media transmission are not intended to be in physical contact ever again once separated into orbit from a launcher&#39;s last stage and umbilical connectors are not designed to be connected again when in orbit. Any electrical interface with the onboard subsystems is mediated by the telecommand system, including monitoring state variables, housekeeping, upgrading of software packages, and troubleshooting of mishaps and failures. Such interventions are limited in nature and cannot be of assistance when, for example, the telecommunication system itself has failed, malfunctioned, or degraded in performance to prevent the spacecraft from performing its intended mission or executing nominal operations. Similarly, a physical failure, such as a battery cell failure, cannot be recovered merely by reprograming the system&#39;s wiring, let alone by upgrading and enhancing the physical building blocks of the spacecraft. 
     In-orbit spacecraft servicing is rarely performed, and when it is, it is typically a costly and specialized endeavor. For example, the servicing of the Hubble Space Telescope required elaborate and one-off specialized hardware and procedures. What is needed is a system and method to service spacecraft that is reliable, relatively inexpensive, and applicable to a wide set of spacecraft. The disclosure solves this need by providing a system and method to service in-orbit spacecraft through the umbilical connector of a client spacecraft. 
     The in-orbit spacecraft servicing enabled by the disclosed system and method may take many forms and may be occasional or chronic. Electric power may be provided to the serviced spacecraft, software upgrades may be provided to include cyber security upgrades, system-level maintenance to include software maintenance may be performed, for example. Orbital maintenance may be performed, to include relatively modest orbital adjustments and attitude control through to transfers between orbits (e.g. transfer from a parking or graveyard orbit to an operational geostationary orbit). The in-orbit servicing may be occasional meaning a specific, relatively short duration servicing is performed, or may be chronic meaning that the servicing spacecraft remains docked with the serviced spacecraft for an extended period. The servicer spacecraft may provide thrust and momentum control of the combined servicer/client spacecraft system, either on an occasional basis or a chronic basis. 
     SUMMARY 
     An in-orbit spacecraft servicing system to provide in-orbit servicing through umbilical connectors of a spacecraft is provided. The spacecraft servicing system uses a computer-controlled manipulator arm which unfurls and connects a servicer umbilical between a servicer spacecraft and an umbilical external connector of a client spacecraft, even though umbilical connectors are originally designed and conventionally used solely for ground-based operations, typically manually connected, and not part of any client docking or capture system. The umbilical external connector of a client spacecraft is typically located on the relatively unpopulated aft spacecraft panel which faces away from the Earth, thereby not interfering with the operational forward panel of the spacecraft which faces the Earth (i.e. nadir). The electrical connection may be used for a suite of purposes, such as electrical power transfer, software upgrades such as security upgrades, client software maintenance or repair, etc. In one embodiment, the servicer umbilical is disconnected from the client spacecraft and furled to its original position on the servicer spacecraft after servicing is completed. In another embodiment, a detachable service package provided by the servicer spacecraft is attached to the client spacecraft and electrically connected through the umbilical external connector of the client spacecraft. 
     In one embodiment, an in-orbit spacecraft servicing system is disclosed, the system comprising: a servicer spacecraft comprising: a servicer body; a set of capture arms extending from the servicer body and operating to engage a client in-orbit spacecraft; at least one servicer umbilical with a servicer umbilical first end attached to the servicer body and a servicer umbilical second end fitted with a servicer umbilical end connector, the servicer umbilical end connector configured to form a connection with a client umbilical connector of the client in-orbit spacecraft; a manipulator arm with a manipulator arm first end coupled to the servicer body and a manipulator arm second end configured to attach to and maneuver the servicer umbilical second end; and a processor operating to control the manipulator arm; wherein: the manipulator arm maneuvers the servicer umbilical second end to form a connection between the servicer umbilical end connector and the client umbilical connector. 
     In one aspect, the connection is an electrical connection. In another aspect, the servicer spacecraft further comprises an auxiliary power supply. In another aspect, the electrical power provided by the auxiliary power supply is transferred from the servicer spacecraft to the client in-orbit spacecraft through the electrical connection. In another aspect, the servicer further comprises a service package detachable from the servicer body and configured to attach to the client in-orbit spacecraft. In another aspect, the service package provides electrical power to the client in-orbit spacecraft through the connection. In another aspect, the set of capture arms engage an interface ring of the client in-orbit spacecraft at a selectable interface ring clocking position. In another aspect, the connection formed between the servicer umbilical end connector and the client umbilical connector remains secure after the manipulator arm detaches from the servicer umbilical end connector. In another aspect, the servicer umbilical comprises a set of electrical cables configured to transfer at least one of electrical power and electrical signals to the client in-orbit spacecraft. In another aspect, the servicer umbilical end connector is coupled to at least one sensor, the at least one sensor providing sensor data to the processor to assist the servicer umbilical end connector to form the connection with the client umbilical connector. In another aspect, the at least one sensor is a micro camera. In another aspect, the servicer umbilical end connector is further coupled to an extension guide, the extension guide forming a cone shaped extension from the servicer umbilical end connector to facilitate alignment of a servicer umbilical end connector with a client umbilical connector z-axis. 
     In another embodiment, an in-orbit spacecraft servicing system is disclosed, the system comprising: a servicer spacecraft comprising: a servicer body; a set of two or more capture arms extending from the servicer body and operating to engage a client in-orbit spacecraft; at least one servicer umbilical with a servicer umbilical first end attached to the servicer body and a servicer umbilical second end fitted with a servicer umbilical end connector, the servicer umbilical end connector configured to form a connection with a client umbilical connector of the client in-orbit spacecraft; a manipulator arm with a manipulator arm first end coupled to the servicer body and a manipulator arm second end fitted with a sensor and configured to maneuver the servicer umbilical second end; an auxiliary power supply; and a processor operating to control the manipulator arm; wherein: the sensor provides sensor data to the processor to assist the servicer umbilical end connector to form the connection with the client umbilical connector; the servicer umbilical comprises a set of electrical cables configured to transfer electrical power and electrical signals to the client in-orbit spacecraft; the auxiliary power supply provides electrical power from the servicer spacecraft to the client in-orbit spacecraft through the servicer umbilical; and the manipulator arm maneuvers the servicer umbilical second end to form a connection between the servicer umbilical end connector and the client umbilical connector. 
     In yet another embodiment, a method of servicing an in-orbit spacecraft is disclosed, the method comprising: providing a servicer spacecraft comprising: a servicer body; a set of capture arms extending from the servicer body and operating to engage a client in-orbit spacecraft; at least one servicer umbilical with a servicer umbilical first end attached to the servicer body and a servicer umbilical second end fitted with a servicer umbilical end connector, the servicer umbilical end connector configured to form a connection with a client umbilical connector of the client in-orbit spacecraft; a manipulator arm with a manipulator arm first end coupled to the servicer body and a manipulator arm second end configured to maneuver the servicer umbilical second end; and a processor operating to control the manipulator arm; coupling the servicer spacecraft and the client in-orbit spacecraft using the set of capture arms; controlling the manipulator arm to position the servicer umbilical second end to a position adjacent the client umbilical connector; and plugging the servicer umbilical end connector into the client umbilical connector; wherein: an electrical connection is formed between the servicer spacecraft and the client in-orbit spacecraft. 
     In one aspect, the method further comprises the step of transferring electrical power from an auxiliary power unit of the servicer spacecraft to the client in-orbit spacecraft through the electrical connection. In another aspect, the method further comprises the step of transferring electrical signals from the servicer spacecraft to the client in-orbit spacecraft through the electrical connection. In another aspect, the method further comprises the step of rotating the servicer umbilical end connector to a selected clock position of the client umbilical connector. In another aspect, the method further comprises the step of processing a set of signals from a sensor mounted on the servicer umbilical second end, the set of signals enabling precise positioning of the servicer umbilical second end to a position adjacent the client umbilical connector. In another aspect, the set of capture arms engage an interface ring of the client in-orbit spacecraft. In another aspect, the set of capture arms are configured to rotate the client in-orbit satellite about a z-axis of the client in-orbit satellite and the manipulator arm operates with three degrees of freedom. 
     The phrases “at least one”, “one or more”, and “and/or” are open-ended expressions that are both conjunctive and disjunctive in operation. For example, each of the expressions “at least one of A, B and C”, “at least one of A, B, or C”, “one or more of A, B, and C”, “one or more of A, B, or C” and “A, B, and/or C” means A alone, B alone, C alone, A and B together, A and C together, B and C together, or A, B and C together. 
     The term “a” or “an” entity refers to one or more of that entity. As such, the terms “a” (or “an”), “one or more” and “at least one” can be used interchangeably herein. It is also to be noted that the terms “comprising”, “including”, and “having” can be used interchangeably. 
     The term “automatic” and variations thereof, as used herein, refers to any process or operation done without material human input when the process or operation is performed. However, a process or operation can be automatic, even though performance of the process or operation uses material or immaterial human input, if the input is received before performance of the process or operation. Human input is deemed to be material if such input influences how the process or operation will be performed. Human input that consents to the performance of the process or operation is not deemed to be “material”. 
     The terms “determine”, “calculate” and “compute,” and variations thereof, as used herein, are used interchangeably and include any type of methodology, process, mathematical operation or technique. 
     The phrase “client spacecraft” means a spacecraft operating in-orbit that is to be serviced, such as a client satellite to include a client communications satellite. 
     The phrase “servicer spacecraft” means a spacecraft that operates in-orbit to perform in-orbit servicing to a client spacecraft. 
     The phrase “umbilical connector” and “client umbilical connector” mean a connector of a client spacecraft that it traditionally used solely on the ground as an electrical connection to a client spacecraft and not intended for use in-orbit, versus a “servicing connector” which is deliberately intended to be used in-orbit for servicing. 
     The phrase “servicer umbilical” means an electrical connector, such as a cable, that connects between a servicer spacecraft and a client umbilical connector and may be similar if not identical to an umbilical used on the ground to connect with a client umbilical connector. The servicer umbilical may connect directly to the servicer spacecraft or may connect by way of an electrical cord, harness, etc. The term “means” as used herein shall be given its broadest possible interpretation in accordance with 35 U.S.C. Section 112, Paragraph 6. Accordingly, a claim incorporating the term “means” shall cover all structures, materials, or acts set forth herein, and all of the equivalents thereof. Further, the structures, materials or acts and the equivalents thereof shall include all those described in the summary, brief description of the drawings, detailed description, abstract, and claims themselves. 
     Various embodiments or portions of methods of manufacture may also or alternatively be implemented partially in software and/or firmware, e.g. analysis of signs. This software and/or firmware may take the form of instructions contained in or on a non-transitory computer-readable storage medium. Those instructions may then be read and executed by one or more processors to enable performance of the operations described herein. The instructions may be in any suitable form, such as but not limited to source code, compiled code, interpreted code, executable code, static code, dynamic code, firmware code, and the like. Such a computer-readable medium may include any tangible non-transitory medium for storing information in a form readable by one or more computers, such as but not limited to read only memory (ROM); random access memory (RAM); magnetic disk storage media; optical storage media; a flash memory, etc. 
     The preceding is a simplified summary of the disclosure to provide an understanding of some aspects of the disclosure. This summary is neither an extensive nor exhaustive overview of the disclosure and its various aspects, embodiments, and/or configurations. It is intended neither to identify key or critical elements of the disclosure nor to delineate the scope of the disclosure but to present selected concepts of the disclosure in a simplified form as an introduction to the more detailed description presented below. As will be appreciated, other aspects, embodiments, and/or configurations of the disclosure are possible utilizing, alone or in combination, one or more of the features set forth above or described in detail below. Also, while the disclosure is presented in terms of exemplary embodiments, it should be appreciated that individual aspects of the disclosure can be separately claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like elements. The elements of the drawings are not necessarily to scale relative to each other. Identical reference numerals have been used, where possible, to designate identical features that are common to the figures. 
         FIG.  1 A  is a perspective view representation of one embodiment of an in-orbit spacecraft servicing system of the disclosure, the embodiment showing a servicer spacecraft docked with a client spacecraft; 
         FIG.  1 B  is a close-up perspective view of the embodiment of an in-orbit spacecraft servicing system of  FIG.  1 A ; 
         FIG.  2    is a perspective view representation of another embodiment of an in-orbit spacecraft servicing system of the disclosure, the embodiment showing a servicer spacecraft docked with a client spacecraft; 
         FIG.  3    is block diagram representation of another embodiment of an in-orbit spacecraft servicing system; 
         FIG.  4 A  is part one of two parts of a flow diagram of a method of use of the embodiment of an in-orbit spacecraft servicing system of  FIG.  3   ; 
         FIG.  4 B  is part two of two parts of a flow diagram of a method of use of the embodiment of an in-orbit spacecraft servicing system of  FIG.  3   ; 
         FIG.  5    is a perspective view representation of another embodiment of an in-orbit spacecraft servicing system of the disclosure, the embodiment showing a servicer spacecraft docked with a client spacecraft, the servicer spacecraft having two manipulator arms each with an integrated servicer umbilical; 
         FIG.  6 A  is a close-up top view of another embodiment of an in-orbit spacecraft servicing system of the disclosure, the embodiment showing a servicer spacecraft docked with a client spacecraft (capture arms not shown for clarity), the manipulator arm in a first manipulator arm state and the servicer umbilical in a first servicer umbilical state; 
         FIG.  6 B  is a close-up top view of another embodiment of an in-orbit spacecraft servicing system of the disclosure, the embodiment showing a servicer spacecraft docked with a client spacecraft (capture arms not shown for clarity), the manipulator arm in a second manipulator arm state and the servicer umbilical in a second servicer umbilical state; 
         FIG.  6 C  is a close-up top view of another embodiment of an in-orbit spacecraft servicing system of the disclosure, the embodiment showing a servicer spacecraft docked with a client spacecraft (capture arms not shown for clarity), the manipulator arm in a third manipulator arm state and the servicer umbilical in a third servicer umbilical state; 
         FIG.  6 D  is a close-up top view of another embodiment of an in-orbit spacecraft servicing system of the disclosure, the embodiment showing a servicer spacecraft docked with a client spacecraft (capture arms not shown for clarity), the manipulator arm in a forth manipulator arm state and the servicer umbilical in a forth servicer umbilical state; 
         FIG.  7    is a flow diagram of a method of use of the operation of the manipulator arm and the servicer umbilical end during plug, service, and unplug operations; 
         FIG.  8    is a close-up perspective view of the client spacecraft end connector as the joined ends of the servicer spacecraft manipulator arm and the servicer spacecraft servicer umbilical approach to form a connection during precise control operations; and 
         FIG.  9    is flow diagram of a method of use of the operation of the manipulator arm and the servicer umbilical end during precise control operations near the client umbilical connector. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to representative embodiments. The following descriptions are not intended to limit the embodiments to one preferred embodiment. To the contrary, it is intended to cover alternatives, modifications, and equivalents as can be included within the spirit and scope of the described embodiments as defined, for example, by the appended claims. 
     Generally, an in-orbit spacecraft servicing system operates to provide in-orbit servicing through available umbilical connectors of a spacecraft. After docking, the spacecraft servicing system uses a manipulator arm which connects a servicer umbilical between a servicer spacecraft and an umbilical connector of a client spacecraft. The umbilical connector is conventionally used solely for ground-based operations, such as system check-out and pre-launch operations. Once established, the electrical connection formed by the servicer umbilical may be used for any number of purposes, to include without limitation electrical power transfer, software upgrades such as security upgrades, addition of enhanced intrusion prevention or cyber security measures, addition of redundancy to the client such as by providing a redundant telemetry, tracking and control (TT &amp; C) subsystem, client software maintenance or repair, etc. In one embodiment, the servicer umbilical is disconnected from the client spacecraft and furled to its original position on the servicer spacecraft after servicing is completed. In another embodiment, the servicer umbilical remains connected to the client spacecraft after servicing is completed. In another embodiment, a service package is attached to an umbilical connector of the client spacecraft and remains with client spacecraft after the servicing spacecraft undocks from the client spacecraft. The service package may provide without limitation a stand-alone power source, a redundant sub-system such as for command and control, etc. 
     The disclosed devices, systems, and methods of use will be described with reference to  FIGS.  1 - 9   . 
       FIGS.  1 - 3  and  5    provide representations of an entire in-orbit spacecraft servicing system (also referred to as “spacecraft servicing system,” “client spacecraft servicing system,” “servicing system,” or simply as “system”).  FIGS.  6  and  8    provide representations of portions of an in-orbit spacecraft servicing system.  FIGS.  4 A-B  provide a sequence of operations or method of use of an entire in-orbit spacecraft servicing system mission (also referred to as “spacecraft servicing system method,” “client spacecraft servicing system method,” “servicing system method,” or simply as “method”).  FIGS.  7  and  9    provide a sequence of operations or method of use of portions of the method of use of  FIGS.  4 A-B  in greater detail than provided in  FIGS.  4 A-B . 
     With attention to  FIGS.  1 A-B , perspective views of one embodiment of an in-orbit spacecraft servicing system  100  are depicted. The in-orbit spacecraft servicing system  100  is shown with servicer spacecraft  110  (also referred to as servicer  110 ) engaged with or docked with client spacecraft  10  (also referred to as client  10 ). 
     The term “engage” and the phrase “engaged with” means to be connected with or to connect with, to include, for example, docking with. The term “dock” and the phrase “docking with” mean to join two separate free-flying space objects, typically including latching or otherwise coupling the two objects by way of a docking connector. A “soft docking” is a docking that does not form a rigid connection between the space objects; a “hard docking” forms a rigid connection between the space objects. 
     Servicer spacecraft  110  forms a hard docking connection with client  10  by way of a set of capture arms  130 , the capture arms  130  engaging interface ring  30 . The interface ring  30  is commonly of a standardized configuration, e.g. of known diameter and of known edge geometry to facilitate docking operations. In other embodiments, the capture arms  130  engage with any available structurally stable component or area of the client body  20 . 
     In the configuration shown in  FIGS.  1 A-B , the interface ring  30  is centered about the client z axis  21  of the client body  20 , and the engaged or docked client  10  and servicer  110  are aligned about a common z axis  21 ,  121 . Stated another way, the servicer z axis  121  is substantially co-axial or substantially common with the client z axis  21 . The phrase “substantially co-axial” and “substantially common” means to a selectable and defined tolerance or deviation. The docking of the servicer  110  with the client  10  via the set of capture arms  130  may be facilitated by geometries or configurations of the capture arms  130 , such as the ends of the capture arms  130 , as described in U.S. Pat. No. 10,611,504 to Halsband et al, incorporated by reference in entity for all purposes. 
     Frame of reference of the in-orbit spacecraft servicing system  100 , illustrating the common servicer z axis  121  and client z axis  21 , is provided as system frame of reference  101 . The z axis points toward Earth (nadir). As such, the servicer  110  is operating at a slightly higher orbit than the client  10 . 
     The client spacecraft  10  comprises a client body  20 , at least one client umbilical connector  40  disposed on or coupled to a surface of the client body  20 , and an interface ring  30 . The servicer spacecraft  110  comprises a servicer body  120 , a set of capture arms  130 , and an integrated or combined manipulator arm  140  and servicer umbilical  150 . (In other embodiments, such as described in  FIGS.  6 A-D , the manipulator arm  140  and servicer umbilical  150  are separate elements). In some embodiments, the client spacecraft  10  comprises more than one client umbilical connector  40 , and/or the servicer spacecraft  110  comprises more than one manipulator arm  40 . 
     The set of capture arms  130  extend from the servicer body  120  of servicer  110  to engage the interface ring  30  (and/or other structurally stable portion of the client body  20 ) and form a rigid or hard docked pair of spacecraft. In the configuration of  FIG.  1   , the servicer  100  comprises two capture arms  130 . Other configurations of capture arms include, e.g., three or four (see  FIG.  2   ) capture arms  130 . 
     As briefly mentioned above, in some embodiments the set of capture arms  130  engage with other than an interface ring of the client  10 , such as by way of one or more extensions or protrusions of the client body  20 , one or more edges of the client body  20 , and other means known to those skilled in the art. In one embodiment, the servicer  110  and the client  10  dock by way of a plate-like body as described in U.S. Pat. Appl. No. 2018/0229865 to Maeda et al, incorporated by reference in entirety for all purposes. In one embodiment, the set of capture arms engage with existing or evolving standardized docking components, to include the NASA Low Impact Docking system (LIDs), and/or docking components adapted from existing components, such the Hubble Space Telescope Soft Capture mechanism (SCM). 
     After docking, the integrated or combined manipulator arm  140  and servicer umbilical  150  maneuver to engage with or plug into the umbilical connector  40 . The umbilical connector  40  has an umbilical connector z axis  41  which is parallel with each of the servicer z axis  121  and client z axis  21 . In order to attempt to engage with or plug into the umbilical connector  40 , the servicer umbilical  150  must be, at minimum, substantially aligned in z axis with the umbilical connector  40  and substantially positioned in an x-y plane just in front of or adjacent to the x-y position of the face of the umbilical connector. In some embodiments of the umbilical connector  40 , a specific rotational orientation of the servicer umbilical  150  is also required (a so-called clocking orientation). Further details of the positioning and/or rotational alignments of the servicer umbilical  150  with respect to the face of the umbilical connector  40  are provided below with respect to  FIGS.  8  and  9   . 
     Once a connection or positive plugging is made between the umbilical connector  40  and the servicer umbilical  150 , electrical communications may be performed between the servicer  110  and the client  10  by way of the servicer umbilical  150 . 
       FIG.  5    is a perspective view representation of another embodiment of an in-orbit spacecraft servicing system  500 , the embodiment very similar to the spacecraft servicing system  100  of  FIGS.  1 A-B  except that the servicer spacecraft  510  has two manipulator arms  144 ,  144 ′ and some details of the client spacecraft  10  have been removed for clarity (e.g. the rocket engine nozzle). 
     The in-orbit spacecraft servicing system  500  is shown with servicer spacecraft  510  engaged with or docked with client spacecraft  10 . The client spacecraft  10  has client body  20 , interface ring  30 , and client umbilical connector  40 . 
     As depicted in  FIG.  5   , the servicer spacecraft  510  has servicer body  520 , a set of two capture arms  130 , and a set of two manipulator arms  140 ,  140 ′. The set of capture arms  130  engage or couple to the interface ring  30  to provide a hard docking of the client  10  and servicer  110 . Each of the two manipulator arms  140 ,  140 ′ comprise an integrated servicer umbilical (meaning each of manipulator arms  140  and  140 ′ comprise a servicer umbilical  150 ). Manipulator arm  140 ′ is depicted in a stowed state or stowed configuration at a position approximately 180 rotational degrees from manipulator arm  140 . Manipulator arm  140  has manipulator arm first end  143  and manipulator arm second end  144 . Manipulator arm first end  143  is attached to or coupled to the body  520  of service spacecraft  510 . Manipulator arm second end  144  is configured to present the end of servicer umbilical to allow electrical connection with client umbilical connector  40  (to be discussed in detail below, e.g. see  FIG.  8   ). Each manipulator arm  140 ,  140 ′ comprises a first end attached to the servicer body  520  and a second end configured to attach to and to maneuver a servicer umbilical to a position adjacent to a client umbilical connector  40  and to plug the servicer umbilical into the client umbilical connector  40 . Each manipulator arm  140 ,  140 ′ is attached to any available structurally sound location on the servicer body  520 . 
       FIG.  2    provides a perspective view representation of another embodiment of an in-orbit spacecraft servicing system  200 . The spacecraft servicing system  200  of  FIG.  2    is similar to the spacecraft servicing system  100  of  FIG.  1    and is adapted from U.S. Pat. No. 10,625,882 to Reitman et al, incorporated by reference for all purposes. 
     With attention to  FIG.  2   , a perspective view of a servicer spacecraft  210  engaged with or docked with a client spacecraft  10  is depicted. The two spacecraft are docked such that a common z axis is shared, as depicted with reference to coordinate frame  201 . 
     Client spacecraft  10  comprises client body  20 , a pair of solar arrays, client umbilical connector  40 , and interface ring  30 . Each of the client umbilical connector  40  and the interface ring  30  are disposed on a surface of the body  20  facing the servicer spacecraft  210 . The client umbilical connector  40  is disposed at approximately a −45 degree rotational position from the y axis of coordinate frame  201 . Note that other positions of a client umbilical connector are possible, to include without limitation  90 ,  180 , and  270  rotational positions (with respect to the z axis) from the depicted client umbilical connector  40 , and any intermediate angle. Also, a client  10  may comprise more than one umbilical connector  40  (as shown, for example, in  FIG.  5   ). 
     Servicer spacecraft  210  comprises a body  220 , a pair of solar arrays, a set of four capture arms  230 , and a set of four thruster arms  235  each with respective thrusters  236 . The thruster arms  235  with respective thrusters  236  provide, among other things, thrust and momentum control of the combined servicer/client spacecraft system. 
       FIG.  3    is block diagram representation of another embodiment of an in-orbit spacecraft servicing system  300 , the spacecraft servicing system  300  similar to the respective spacecraft servicing systems  100 ,  200 ,  500  of  FIGS.  1 A-B ,  2 , and  5  with the addition of several components or elements. Client spacecraft  10  comprises client body  20 , interface ring  30 , and client umbilical connector  40 . 
     The servicer spacecraft  310  comprises body  320 , a set a capture arms  130 , a manipulator arm  140 , and a servicer umbilical  150 . Also, the servicer spacecraft  310  comprises a servicer body  320 , capture arms  130 , manipulator arm  140 , servicer umbilical  150 , processor  360 , auxiliary power  380 , and detachable service package  370 . 
     The processor  320  provides control and management of the components of the servicer spacecraft  310  that enable the servicing of the client spacecraft  10  by way of the servicer umbilical  150 . Specifically, the processor  320  controls or operates the manipulator arm  140  in maneuvering the servicer umbilical  150  to engage with or plug into the client umbilical connector  40 , such that electric communication (e.g. power transfer, signal transfer, etc.) may be provided between the servicer  310  and the client  10 .  FIGS.  4 A-B  provide details of such operation and control of the manipulator arm  140  and servicer umbilical  150 . The processor  360  controls the set of capture arms  130 . In some embodiments, the operation of the capture arms  130  is controlled partially or completely by another processor of the servicer spacecraft (not shown). In one embodiment, the processor  320  does not control the capture arms  130 . In one embodiment, the processor  320  controls the manipulator arm  140 , detachable service package  370 , auxiliary power  380 , and/or the servicer umbilical  150 . The processor  320  may operate in any number of control modes for one or more components. For example, the processor  320  may operate the manipulator arm  140  in a first positioning mode that positions an attached servicer umbilical  150  to adjacent a client umbilical connector  40 , and a second precise positioning mode that performs plugging in or plugging out maneuvers of the servicer umbilical  150  with the client umbilical connector  40  (see e.g.  FIGS.  8 - 9    for additional details). 
     The servicer spacecraft  310  also includes an auxiliary power supply  380  which may be used to supply electrical power to the client  10  by way of the servicer umbilical  150  when the servicer umbilical  150  is connected to or plugged into the client umbilical connector  40 . Alternatively, or additionally, a main or primary power supply (not shown) of the servicer spacecraft  310  may be used to supply power to the client through the servicer umbilical  150 . Such a main power supply and the auxiliary power supply  380  may be operated in a coordinated manner by way of the processor  360 . For example, the servicer spacecraft&#39;s main power supply may only provide power to the client  10  when the main power supply is not being used, or drawn from, to operate servicer devices such as (electric) thrusters  236 , the processor  380  otherwise providing power to the client  10  using the auxiliary power supply  380 . Also, one or both of the main power supply and the auxiliary power supply may, through control of the processor  320 , withdraw electrical power from the client in addition to delivering electrical power to the client. 
     A detachable service package  370  is attached to or affixed to the client spacecraft  10  to provide servicing to the client  10  after undocking of the servicer spacecraft  310 . The detachable service package  370  may provide any number of functions, to include electrical power, redundancy functions (e.g. back-up command and control, back-up communications, additional or redundant telemetry, tracking and control subsystems), upgrade features (e.g. enhanced security features such as cyber security or protection features), and the like. The detachable service package  370  may be designed to enable or perform client-specific functions, e.g. execute a trouble-shooting protocol for an errant hardware or software module. The detachable service package  370  may remain attached to and/or electrically connected with the client  10  after the servicer  310  undocks from the client  10 . The detachable service package  370  is positioned to engage with, and in some embodiments attach to, the client  10  by way of the manipulator arm  140 . 
     In one embodiment, the detachable service package  370  is electrically connected to the servicer at a first end of the service package  370  and is electrically connected to the client  10  at a second end of the service package  370  through a client umbilical connector  40 . In some embodiments, one or more servicer umbilicals  150  attach or connect with the service package  370  at one or both of the first end of the service package  370  and the second end of service package  370 . In one embodiment, the service package  370  directly connects with the client umbilical connector  40 . In one embodiment, the service package  370  connects with the client umbilical connector  40  without use of or connection to a servicer umbilical  150 . Operation of the detachable service package  370  is described in more detail with regard to  FIGS.  4 A-B . 
       FIGS.  4 A-B  provide a flow diagram of one method of use  400  of the embodiment of an in-orbit spacecraft servicing system  300  of  FIG.  3   . However, aspects and features of any of the  FIGS.  1 ,  2  and  4 - 9    may be referenced to enhance the disclosure of the method of use. For example, elements described in  FIGS.  6 A-D  will be referenced during the description of several steps of the method  400 . Generally, the method  400  starts at step  404  and ends at step  460 . Any of the steps, functions, and operations discussed herein can be performed continuously and automatically. In some embodiments, one or more of the steps of the method of use  400 , to include steps of the method  400 , may comprise computer control, use of computer processors, and/or some level of automation. Indeed, most if not all of the steps of method  400  are performed automatically, principally if not entirely by processor  320 . However, in some embodiments some of the steps or parts of some of the steps are performed in concert with or exclusively by human intervention. For example, once an electrical connection is established between servicer spacecraft  310  and client spacecraft  10  at step  440 , a human operator may intervene to direct specific software to be uploaded to the client spacecraft  10 , as discussed below. 
     The steps are notionally followed in increasing numerical sequence, although, in some embodiments, some steps may be omitted, some steps added, and the steps may follow other than increasing numerical order. A user may interact or perform one or more of the described steps be using a display/GUI. The phrase “user interface” or “UI”, and the phrase “graphical user interface” or “GUI”, means a computer-based display that allows interaction with a user with aid of images or graphics. 
     After starting at step  404 , the method  400  proceeds to step  408 . At step  408 , the servicer spacecraft  310  positions to engage or dock with the client spacecraft  10 . The client spacecraft may be in any of a number of orbit types, to include Geostationary Earth Orbit (GEO), Low Earth Orbit (LEO), Medium Earth orbit (MEO), interplanetary transfer orbits, Earth-Moon Lagrange points, and any stable orbit configuration. In one embodiment, the client spacecraft is a client satellite, such as a communication satellite. In one embodiment, the client satellite operates at one of GEO or LEO. The client spacecraft may be operating in a stable configuration or an uncontrolled configuration. In either client configuration, at step  408 , the servicer spacecraft  310  is positioned so as to face the client spacecraft  10  without relative motion between the two spacecraft, thus enabling docking of the two spacecraft. Stated another way, at step  408 , the servicer  310  is positioned such that capture arms  130  face the interface ring  30  and the client umbilical connector  40  of the client  10 , such that the capture arms  130  may extend to dock with the client  10 . In one embodiment, the client  10  is a tumbling (aka uncontrolled) spacecraft, and the positioning of the servicer  310  relative to the client  10  is as described in  ELSA - D: An In - orbit End - of - Life Demonstration Mission , Blackerby et al, IAC-18, Sep. 14, 2018, incorporated by reference in entirety for all purposes. At the completion of step  408 , the method  400  proceeds to step  412 . 
     At step  412 , the servicer spacecraft  310  docks with the client spacecraft  10  using the set of capture arms  130 . The capture arms  310  may be controlled exclusively by the processor  320 , exclusively by a core or servicer body processor other than the processor  320 , or a combination of both. The capture arms  130  may engage an interface ring  30  of the client  10 , and/or may engage a component or portion of the client  10  other than a client interface ring  30 . In one embodiment, the set of capture arms  30  engage and dock with one or more physical extensions of the body  20  of the client  10 . At the completion of step  412 , the method  400  proceeds to step  416 . 
     At step  416 , the processor  320  activates the manipulator arm (or set of manipulator arms, such as in the system  500  of  FIG.  5    wherein the servicer  510  has two manipulator arms). The activation may involve diagnostic, health, and/or system checks to ensure proper operation of the manipulator arm  640  (See  FIG.  6 A-D  for three-digit elements beginning with a 6). The manipulator  640  may have an initial or stowed configuration when the servicer  310  first docks with a client  10 , such as depicted in  FIG.  6 A . At the completion of step  416 , the method  400  proceeds to step  420 . 
     At step  420 , the servicer umbilical  650  is prepared to receive the manipulator arm  640 . More specifically, the umbilical arm  650  is prepared to receive the manipulator arm second end  644 , the manipulator arm second end  644  being opposite to the manipulator arm first end  643 . The manipulator arm first end  643  is attached to the body  620  of the servicer  610 . The preparation of the servicer umbilical  650  may include detaching the servicer umbilical second end  654  from engagement with the body  620  of the client  610 , such as detachment from a servicer cavity  671  of the body  620  of the servicer  610 . The preparation of the servicer umbilical  650  may also include diagnostic, health, and/or system checks of the servicer umbilical  650 . In one embodiment, the servicer umbilical  650  initial stowed configuration may be a coiled configuration, as shown in  FIG.  6 A . At the completion of step  420 , the method  400  proceeds to step  424 . 
     At step  424 , the servicer umbilical  650  is connected with the manipulator arm  640 . More specifically, the manipulator arm second end  644  is connected with the servicer umbilical second end  654  so as to present an external face of the servicer umbilical second end  654  that is able to connect or plug into the client umbilical connector  40 . The manipulator arm second end  644  is adapted or configured such that, upon rotation and/or pivoting, the formerly internally facing end of the servicer umbilical second end  654  is rotated to face outwards (compare the relative positioning of manipulator arm second end  644  and servicer umbilical second end  654  in  FIG.  6 B  and  FIG.  6 C ). In one embodiment, the interaction or engagement of the servicer umbilical second end  654  and the servicer umbilical second end  654  uses techniques or elements described in WIPO Application WO 2019/068547 to Schadler et al, incorporated by reference for all purposes. The final configuration of the joined or connected pair of manipulator arm second end  644  and servicer umbilical second end  654  is described with respect to  FIG.  8   . (Note that in some configurations, such as that depicted in  FIGS.  1 B and  5   , the manipulator arm and servicer umbilical are an integrated unit, thereby obviating the need for step  424 ). At the completion of step  424 , the method  400  proceeds to step  428 . 
     At step  428 , the processor  360  directs or controls the manipulator arm  140 , with attached servicer umbilical second end  654 , to a position adjacent or near the client umbilical connector  40 , as shown in  FIGS.  6 C-D . The processor  360 , as briefly discussed above, may operate in a set of control modes when controlling or maneuvering the manipulator arm  140 . The set of control modes may receive a variety of sensor inputs to perform the control modes. For example, the processor  360  may initially operate or control the manipulator arm  140  in a first positioning mode with aid of sensor data provided by one or more sensors mounted on the servicer body  320 , such as a wide field of view camera. In another example, the processor  320  may control the manipulator arm with aid of one or more sensors mounted on the manipulator arm  140 , such as at or near the manipulator arm second end  644 , and/or mounted on or near the servicer umbilical second end  654 , such as a radar or micro camera (see  FIG.  8   ). 
     The processor  360  may combine available sensors to position and maneuver the manipulator arm  140  in any number of control modes in any number of control law schemes known to those skilled in the art, to include adaptive control, stochastic control, neural network, AI-based or other machine learning control, etc. The processor  360  may employ techniques of computer vision to assist or enable control of the manipulator arm  140 . The manipulator arm may operate autonomously, semi-autonomously, or manually during all or portions of operation. (Manual input provided by a ground-based operator communicating with the processor  360  by way of ground-based command entries). At the completion of step  428 , the method  400  proceeds to step  432 . 
     In one embodiment, the processor monitors the kinematics of the manipulator arm  140  through postures of the joints or pivots of the manipular arm  140  and/or the posture of the manipulator arm second end  644  to control the motion of the manipulator arm  140 . In such an embodiment, with knowledge of the geometries of the client spacecraft (e.g. the location of the targeted client umbilical connector and any obstacles the manipulator arm may encounter when maneuvering to the umbilical connector), the manipulator arm second end  644  with attached servicer umbilical may maneuver the servicer umbilical to a position near or adjacent the umbilical connector, if not plug the servicer umbilical into the umbilical connector. 
     At step  432 , a query is made as to whether a rotation of the client spacecraft  10  about interface ring  30  is available and to be employed, such rotation performed by the set of capture arms  130 . Such a capability allows selectable relative positioning between the client umbilical connector  40  and the manipulator arm second end  644  (and thus also the coupled servicer umbilical second end  654 ), and thereby reduces the degrees of freedom (DOF) required of the manipulator arm. Stated another way, if a rotation of the client spacecraft  10  about interface ring  30  is available, the degrees of freedom required to enable the connection between the servicer umbilical second end  654  and the client umbilical connector  40  may be shared between the manipulator arm  640  and the connection between the client  10  and the servicer  110 . For example, if the servicer  310  is docked to the client  10  through the client interface ring  30  in such a way that the client  10  is in a predetermined orientation relative to the servicer  310 , and the servicer  110  can furthermore rotate around the interface ring  30  and clamp to it in any required clocking, than only three degrees of freedom are required for the manipulator arm  140 , namely radial and axial translations relative to the common body Z-axis ( 121  and  21  of  FIG.  1 A ) of the tandem or paired spacecraft system in order to bring the servicer umbilical second end  654  along the plugging axis ( 41 ,  646 , and  656  of  FIG.  6 D ), and a rotation of the servicer umbilical second end  654  to orient the correctly around the plugging axis. (Among other things, a reduced DOF manipulator arm may offer advantages relative to a higher DOF manipular arm such as reduced cost, reduced stowage space requirements, reduced power requirements, increased reliability, etc.) 
     If the response to the query of step  432  is Yes, then the method  400  proceeds to step  433  wherein the client  10  is rotated or captured in the manner described above so as to reduce the degrees of freedom required of the manipulator arm  140 . At the completion of step  433 , the method  400  continues to step  434 . At step  434 , a manipulator arm  140  of reduced degree of freedom, as described, may be used, such as a manipulator arm  140  of three DOF, to plug the servicer umbilical second end  654  to the client umbilical connector  40 . Additional details of the plugging of the servicer umbilical second end  654  with to the client umbilical connector  40  are provided in  FIGS.  7 - 9   . At step  434 , a manipulator arm  140  of at least 3 DOF may also be used, to include a manipulator arm of six DOF. At the completion of step  434 , the method  400  proceeds to step  440 . 
     If the response to the query of step  432  is No, then the method proceeds to step  436 , wherein a six DOF manipulator arm  140  is used to plug the servicer umbilical second end  654  to the client umbilical connector  40 . Additional details of the plugging of the servicer umbilical second end  654  with to the client umbilical connector  40  are provided in  FIGS.  7 - 9   . At the completion of step  436 , the method  400  proceeds to step  440 . 
     At step  440 , a connection between the servicer spacecraft  310  and the client spacecraft  10  is established. More specifically, a physical connection and/or an electrical connection is made between the servicer umbilical second end  654  and the client umbilical connector  40 . The electrical connection allows any number of servicing functions to be performed to the client  10  by the servicer  310 . For example, the auxiliary power  380  may provide, as controlled by the processor  320 , electrical power to the client  10 . As another example, electrical signals may be transferred to perform status or maintenance functions, e.g. perform diagnostics on the client. As another example, the electrical connection may be used to add or enhance cyber protection through the servicer  310  to the client  10 , and/or to add redundancy to the client  10 , such as by providing a redundant telemetry, tracking and control (TT &amp; C) subsystem to the client  10 . The electrical connection between the servicer  310  and the client  10  may be used for communications in either or both directions, e.g. diagnostic or status data may be transferred from the client  10  to the servicer  310 , a client data back-up may be performed by data transfer from the client  10  to the servicer  310 , and software upgrade routines may be transferred from the servicer  310  to the client  10 . At the completion of step  440 , the method  400  proceeds to step  444 . 
     At step  444 , a query is made as to whether the servicer spacecraft  310  has a detachable service package  370 , the detachable  370  to be affixed or coupled to the client spacecraft  10 . If the reply to the query of step  444  is Yes, the method  400  proceeds to step  445  wherein the detachable service package  370  is detached from the servicer  310  by the manipulator arm  140  and positioned and secured to a selectable location on or in the client  10 . As discussed above, the detachable service package  370  may be configured to connect with one or more client umbilical connectors  40  of the client  10 , either directly or by way of a servicer umbilical  150 . After completion of step  445 , the method  400  proceeds to step  446 , wherein the manipulator arm  140  detaches from the service package  370 . At the completion of step  446 , the method  400  proceeds to step  448 . If the reply to the query of step  444  is No, the method  400  proceeds to step  448 . 
     At step  448  the servicer umbilical second end  654  is detached or unplugged from the client umbilical connector  40  and the servicer umbilical  40  is stowed in or on the servicer spacecraft  310 . Generally, the unplugging of the servicer umbilical second end  654  from the client umbilical connector  40  proceeds in a similar but opposite manner to the plugging, e.g. the servicer umbilical second end  654  is rotated in an opposite angular direction along plugging z axis  41  to that required during plugging and the servicer umbilical second end  654  is retraced or pulled away from the client umbilical connector  40 . In one embodiment, the servicer umbilical  40  is stowed in a configuration similar to the initial stowed position of  FIG.  6 A . At the completion of step  448 , the method  400  proceeds to step  452 . 
     At step  452 , the manipulator arm  140  is stowed on or within the servicer spacecraft  310 . In one embodiment, the manipulator arm  140  is stowed in a configuration similar to the initial stowed position of  FIG.  6 A . At the completion of step  452 , the method  400  proceeds to step  456 . 
     At step  456 , the servicer spacecraft  310  undocks from the client spacecraft  10 , and the method  400  proceeds to step  460  wherein the method ends. 
       FIGS.  6 A-D  provide a sequence of close-up top views of another embodiment of an in-orbit spacecraft servicing system  600 . The embodiment comprises a servicer spacecraft  610  comprising a servicer body  620 , a single manipulator arm  640  and a single servicer umbilical  650  stowed within a servicer cavity  671 , and a client  10  with a single umbilical connector  40  disposed on client body  20 . The set of  FIGS.  6 A-D  are further described with regards to the method  700  of  FIG.  7   . 
     The manipulator  640  comprises a manipulator first end  643  attached to or secured to a servicer manipulator arm attachment  622 , the servicer manipulator arm attachment  622  attached to or secured to the servicer body  620 . The manipulator arm  640  further comprises a medial portion  645  comprising a set of two pivot joints, and a manipulator second end  644  configured to engage with or couple to the servicer umbilical second end  654 . The set of joints of the manipulator arm  640  operate as pivot joints to enable pivoting or rotation between connected or attached components. For example, the pivot associated with manipulator first end  643  enables rotation of the manipulator first end  643  about the servicer manipulator arm attachment  622 . Other configurations joints and components of the manipulator arm  640  are possible, to include alternative and/or additional joints than the pivot joints depicted, as known to those skilled in the art. 
     The manipulator arm  640  is a six DOF manipulator arm and is depicted in a sequence of states or configurations in each of  FIGS.  6 A-D . Generally, the manipulator arm  640  operates to attach the manipulator second end  644  to the servicer umbilical second end  654  as depicted in  FIG.  6 B , to maneuver the servicer umbilical second end  654  to a position adjacent the umbilical connector  40  in  FIG.  6 C  (requiring, among other things, a 3-d positioning of the servicer umbilical second end  654  adjacent the umbilical connector  40 ), to align the servicer umbilical second end  654  in z axis with the plugging z axis  41  of the umbilical connector  40  as depicted in  FIG.  6 D , and to plug in the servicer umbilical second end  654  with the umbilical connector  40 . 
     The servicer umbilical  650  comprises a servicer umbilical first end  623  attached to or secured to a servicer umbilical attachment  623 , the servicer umbilical attachment  623  in turn attached to or secured to the servicer body  620 . The servicer umbilical  650  further comprises a servicer umbilical second end  654  configured to engage with or couple to manipulator second end  644 . The servicer umbilical  650  is depicted in a sequence of states or configurations in each of  FIGS.  6 A-D . 
     In  FIG.  6 A , the servicer umbilical  650  is depicted in a first (or stowed) servicer umbilical state, wherein the servicer umbilical  650  is stowed internally to the body  620  of the servicer  610  within servicer cavity  671  in a coiled configuration. Other stowed positions or configurations of the servicer umbilical  650  are possible, to include partially or entirely external to the body  620  (not shown), not unlike the manner of stowage of the manipulator arm  640 . 
       FIG.  6 B  depicts the manipulator arm  640  and the servicer umbilical  650  each in a respective second state, wherein the manipulator second end  644  is engaged with the servicer umbilical second end  654 , the servicer umbilical  650  remaining in a coiled state or coiled configuration. 
       FIG.  6 C  depicts the manipulator arm  640  and the servicer umbilical  650  each in a respective third state, wherein the manipulator second end  644  is engaged with the servicer umbilical second end  654 , the coupled or engaged pair of servicer umbilical second end  654  and manipulator second end  644  moving toward the umbilical connector  40  of client  10 . In this third state, the coupled engaged pair of servicer umbilical second end  654  and manipulator second end  644  have an axial relative z axis of  644 ,  654  and the umbilical connector  40  has a z axis  41  (also referred to as a plugging axis  41 ). 
       FIG.  6 D  depicts the manipulator arm  640  and the servicer umbilical  650  each in a respective fourth state, wherein the manipulator second end  644  remains engaged with the servicer umbilical second end  654 , the coupled or engaged pair of servicer umbilical second end  654  and manipulator second end  644  generally aligned with the umbilical connector  40  of client  10 . In this fourth state, the coupled engaged pair of servicer umbilical second end  654  and manipulator second end  644  have an axial relative z axis of  644 ,  654  generally or substantially aligned with the plugging axis  41  of the umbilical connector  40 , and the servicer umbilical second end  654  is positioned to plug into the umbilical connector  40  (see  FIGS.  7 - 8    and associated description). 
       FIG.  7    provides a flow diagram of operations of the manipulator arm and servicer umbilical to plug and unplug with the umbilical connector. The method  700  of  FIG.  7    will be described with reference to other figures of the disclosure, in particular  FIGS.  3 ,  4 A -B, and  6 A-D. 
     Generally, the method  700  starts at step  704  and ends at step  740 . Any of the steps, functions, and operations discussed herein can be performed continuously and automatically. In some embodiments, one or more of the steps of the method of use  700 , to include steps of the method  700 , may comprise computer control, use of computer processors, and/or some level of automation. Indeed, most if not all of the steps of method  700  are performed automatically, principally if not entirely by processor  320 . However, in some embodiments some of the steps or parts of some of the steps are performed in concert with or exclusively with human intervention. For example, once an electrical connection is established between servicer spacecraft  310  and client spacecraft  10  at step  724 , a human may intervene to direct specific servicing activities for the client spacecraft  10 . The steps are notionally followed in increasing numerical sequence, although, in some embodiments, some steps may be omitted, some steps added, and the steps may follow other than increasing numerical order. When the method references a user, the user may be one or more users. A user may interact or perform one or more of the described steps be using a display/GUI. 
     After starting at step  704 , the method  700  proceeds to step  708 . At step  708 , the manipulator arm  140  is activated and the servicer umbilical  150  is prepared to receive the manipulator arm  140 . The step  708  is very similar to the step  416  of method  400  wherein the manipulator arm  140  is unstowed, turned on, and checked for operation, and the step  420  of method  400 , wherein the servicer umbilical  150  is unstowed and similarly checked for operation.  FIG.  6 A  depicts the step  708  with respect to a manipulator arm  140  and servicer umbilical  150  of a servicer  610 . If one or both of the servicer umbilical  150  and manipulator arm  140  are stowed within a compartment or cavity of the body  320  of the servicer  310 , such a compartment is opened to allow the exit and operation of the servicer umbilical  150  and/or manipulator arm  140 . After the completion of step  708 , the method  700  proceeds to step  712 . 
     At step  712 , the manipulator arm second end  644  is connected to the servicer umbilical second end  654 , as shown in  FIG.  6 B . The step  712  is similar to the step  424  of method  400 . At step  712 , electronics of the manipulator arm  140 , such as electronics of the manipulator arm second end  644 , may form an electrical connection with the servicer umbilical second end  654 . After the completion of step  712 , the method  700  proceeds to step  716 . 
     At step  716 , the manipulator arm second end  644 , as connected to the servicer umbilical second end  654 , maneuvers toward the client umbilical connector  40 , as shown in  FIG.  6 C . The step  716  is similar to the step  428  of method  400 . During step  716 , the servicer umbilical  150  unfurls or uncoils. In one embodiment, during step  716  additional sensors associated with the manipulator arm second end  644  may be activated, such additional sensors enabling precise control of the manipulator arm second end  644  and further described with respect to  FIG.  8    below. After the completion of step  716 , the method  700  proceeds to step  720 . 
     At step  720 , the z axes of the joined or coupled manipulator second end  644  and servicer umbilical second end  654  are substantially aligned with the z axis of the client umbilical connector  41 , as depicted in  FIG.  6 D . Stated another way, the shared manipulator second end  644  z axis  646  and servicer umbilical second end  654  z axis  656  is substantially aligned with the plugging axis  41  of the umbilical connector  40 . After the completion of step  720 , the method  700  proceeds to step  724 . 
     At step  724 , the servicer umbilical second end  654 , by way of the maneuvering and control of the manipulator second end  644  by the processor  320 , is plugged into the umbilical connector  40  along plugging axis  41 . The step  724  is similar to the alternative steps  436  and  434  of method  400 . Additional details of the step  724  plugging operations are provided with respect to  FIGS.  8  and  9   , to include any rotational requirements of the servicer umbilical second end  654  to satisfy clocking requirements of the umbilical connector  40 . After the completion of step  724 , the method  700  proceeds to step  728 . 
     At step  728 , the client spacecraft  10  is serviced as described above. The servicing may comprise transfer of electrical power to client  10  by transfer of electrical energy a stored in auxiliary power  380 , and one-way or two-way transfer of electrical signals e.g. transfer software or receive spacecraft data, addition of enhanced intrusion prevention or cyber security measures, addition of redundancy to the client such as by providing a redundant telemetry, tracking and control subsystem, client software maintenance or repair, etc. 
     During the servicing of the client spacecraft  10  by way of client umbilical connector  40 , the manipulator arm  140  may or may not remain engaged with the umbilical connector  40 , and specifically may or may not remain engaged with the servicer umbilical second end  654 , in embodiments of the system wherein the servicer umbilical second end  654  is configured to remain engaged with, or plugged into, the client umbilical connector  40  without need of the continuous engagement of the manipulator arm  140 . Stated another way, in some embodiments the manipulator arm  140  is not required to remain attached to the servicer umbilical during servicing of the client because the servicer umbilical second end  654 , once plugged into the client umbilical connector  40 , remains securely plugged in without requiring continued connection (e.g. forward pressure along the plugging axis) with the manipulator arm  140 . Such an unaided continuous plug-in of the servicer umbilical into the umbilical connector  40  may be enabled by, among other things, geometries of the plug-in (e.g. required clocking and rotation, discussed below), friction or interference fitting of the plug-in, etc. The ability of the servicer umbilical to remain plugged into the umbilical connector  40  without aid of the manipulator arm  140  is advantageous as such a capability enables, among other things, for the manipulator arm to perform other functions during client servicing, such as attaching a service package to the client, attaching a second servicer umbilical to a second umbilical connector, etc. After the completion of step  724 , the method  700  proceeds to step  732 . 
     At step  732 , the servicer umbilical second end  654  is unplugged or disconnected from the umbilical connector  40  along the plugging axis  41 . Step  732  is similar to aspects of step  448  of method  400 . In one embodiment wherein the umbilical connector has clocking requirements, the servicer umbilical second end  654  is first rotated by the manipulator arm second end  644  before being axially pulled away or out from the umbilical connector  40 . After the completion of step  732 , the method  700  proceeds to step  736 . 
     At step  736 , the manipulator arm  640  first stows the servicer umbilical  650  to within the cavity  671 , requiring furling or curling up of the servicer umbilical  650 . Step  736  is similar to aspects of steps  448  and  452  of method  400 . In one embodiment, the stowage of the servicer umbilical  650  is facilitated or assisted by a mechanism contained within or adjacent to the cavity  671 , such a mechanism optionally controlled by the processor  360 . For example, the mechanism may comprise a tether that may be reeled in and out with the extension or unfurling of the servicer umbilical  650 , a spring or other retraction mechanism, an electromagnet, etc. After the manipulator arm  640  stows the servicer umbilical  650 , the manipulator arm itself is stowed. After completion of step  736 , the method  400  proceeds to step  740  and the method  4500  ends. 
       FIG.  8    depicts a close-up perspective view  800  of the servicer umbilical connector second end  954  and client spacecraft end connector  40  as the joined ends of the servicer spacecraft manipulator arm  140  and the servicer spacecraft servicer umbilical  150  approach the end connector  40  to form a connection. 
     The manipulator arm second end  844 , as engaged with or coupled to the servicer umbilical second end  854 , is shown in  FIG.  8    approaching the client spacecraft umbilical connector face  982  of servicer umbilical second end  954 . Coordinate system  801  shows a plugging axis z aligned for each of these components. Stated another way, umbilical connector z axis  956  is aligned with the common z axis of the connected manipulator arm second end  844  and servicer umbilical second end  854 . 
     Umbilical connector face  982  of umbilical connector second end  954  is depicted extended from body  820  of client spacecraft with a set of three clocking divots  991 ,  992 , and  993 . The set of clocking divots or apertures or voids  991 ,  992 ,  993  are positioned at 90-degree radial offsets from one another in a symmetrical arrangement. The umbilical connector face  954  also comprises a pair of pin receiver divots  997  and  998 , and a rectangular pin port  995 . The pair of pin receiver divots  997  are disposed at opposing ends of umbilical connector face x axis  982   x.    
     Other configurations of connections of the umbilical connector face  954  are possible—the version depicted in  FIG.  8    is for illustrative purposes only. Any commercially available configuration of connections of the umbilical connector face  954  is possible as known to those skilled in the art. For example, the umbilical connector face  954  and/or the client spacecraft end connector  40  generally may be configured as described in the  Falcon  9  Lunch Payload User&#39;s Guide , Rev. 1, Space Exploration Technologies, 09-S-0347, and/or in the  Ariane  5  User&#39;s Manual , Issue 5 Revision 1, July 23011, Arianespace, both of which are incorporated by reference in entirety for all purposes. In some embodiments of the umbilical connector face  954  and/or the client spacecraft end connector  40 , one or more latch devices (either latch receivers or latch extensions) are conventionally used to connect the servicer umbilical with a client umbilical connector when such connection is conventionally made during ground operations. Such latch devices, or other connection mechanisms known to those skilled in the art, may or may not be additionally or alternatively associated with the system of the disclosure. 
     Servicer umbilical second end face  882  of servicer umbilical second end  854  has an opposing set of connectors to engage with or connect with the umbilical connector face  982 . Specifically, servicer umbilical second end face  882  has a set of three closing extensions  891 ,  892 , and  893  (which engage with respective clocking divots  991 ,  992 , and  993 ), a pair of pins  897  and  898  (which engage with respective pin receiver divots  997  and  998 ), and a rectangular pin plug  895  (which engages with rectangular pin port  995 ). The servicer umbilical second end face  882  is fitted within a manipulator arm second end lip  881 . The servicer umbilical second end face  882  has a servicer umbilical second end face x axis  882   x  and a servicer umbilical second end face y axis of  882   y , the servicer umbilical second end face  882  offset in rotation by servicer umbilical second end face angle γ. 
     Manipulator arm second end lip  881  comprises a sensor  885  and a set of extension guides  886 ,  887  to assist in precise control or positioning of the servicer umbilical second end face  882 . Other configurations of sensors and extensions are possible. 
     In one embodiment, the sensor  885  is a camera, such as a visible band camera, infrared camera, or other camera. The sensor  885  senses or measures sensor data that is provided to the processor  360 . The sensor  885  data may comprise, for example, images e.g. as collected from a camera, ranging data e.g. as collected from a radar or lidar, force data as e.g. collected from a force sensor, strain data as collected from a strain gauge, and physical positioning sensor or apparatus (such as the extension guides  886 ,  887 ). In one embodiment, the sensor is a micro camera, such as manufactured by Scoutcam™ and/or as described in U.S. Pat. No. 10,420,216 to Govrin et al, incorporated by reference in entirety for all purposes. The sensor  885  may be a set of sensors comprising radar, ladar, lidar, electromagnetic, and other sensors known to those skilled in the art. The one or more sensors  885  provide sensor measurements to the processor to assist in or to enable the control of the servicer umbilical second end face  882  by way of the control of the manipulator arm second. 
     In some embodiments, additional or alternative sensors may be mounted on one or more of the servicer body or servicer components to assist and/or enable maneuvering of the manipulator arm to adjacent the client umbilical connector and/or through to plugging/unplugging operations. For example, a sensor, such as a wide field of view camera, may be mounted on a surface of the servicer body, e.g. on the surface facing the client umbilical connector, to allow for general or primary maneuvering of the manipulator arm. In one embodiment, one or more rendezvous sensors, such as rendezvous cameras, are employed as sensors to assist or enable the maneuvering of the manipulator arm. As another example, a sensor, such as lidar, may be positioned or mounted on the manipulator arm second end  844  to assist and/or enable maneuvering of the manipulator arm, such as when engaged with or attached to the servicer umbilical second end  654 . 
     The set of extension guides  886 ,  887  define a cone shaped extension to assist in precise control or positioning of the servicer umbilical second end face  882 . Specifically, the set of extension guides  886 ,  887  may, in one configuration, physically engage a perimeter surface surrounding the body  820  of the client spacecraft. In one configuration, the set of extension guides  886 ,  887  are retractable. In one embodiment, a cone-like guide is fitted to the end of the servicer umbilical second end face  882  and/or the manipulator arm second end  844  to assist in precise control of the servicer umbilical second end face  882 . In one embodiment, a protective cover is fitted to extend from the servicer umbilical second end face  882  and/or the manipulator arm second end  844  to shroud or cover the connected interface of the servicer umbilical connector second end  954  when plugged into the client spacecraft end connector  40 . 
     As briefly discussed above, in some embodiments the manipulator arm  140  is not required to remain attached to the servicer umbilical during servicing of the client because the servicer umbilical second end face  882 , once plugged into the client umbilical connector second end  954 , remains securely plugged in without requiring continued connection with the manipulator arm  140 . The unaided continuous plug-in of the servicer umbilical into the umbilical connector  40  may be provided by features of the servicer umbilical second end  854 . For example, the servicer umbilical second end  854  may form an interference fit or friction fit with the client umbilical connector second end  954  such that once the two are plugged-in together, the connection is stable and secure. In another example, the servicer umbilical second end  854  may comprise slots or other geometries or features known to those skilled in the art to provide a secure and stable physical connection. A “secure and stable connection” means a connection that remains connected, even when in receipt of relatively minor force disturbances such as vibration, force impacts such as jarring, and twists or rotations. In another example, the set of male/female clocking connections (the set of three closing extensions  891 ,  892 , and  893  of servicer umbilical second end face  882  which engage with respective clocking divots  991 ,  992 , and  993 ) provide a stable and secure connection. 
     It is noted that during plugging (and unplugging) operations between the servicer umbilical second end  854  and the client umbilical connector second end  954 , a force may be imparted to one or more components of the joined servicer-client system, e.g. the set of capture arms, the manipulator arm, etc. In the examples described above involving an interference fit and clocking fits, such forces would be transferred to one or more system components. 
     In some embodiments and/or operations, no such forces, or de minimus forces, are so imparted during plugging and/or unplugging. For example, in the configuration of  FIG.  7   , the set of extension guides  886 ,  887  may permit or enable plugging and unplugging operations that transfer no or minimal forces to the system. In one embodiment, the set of extension guides  886 ,  887  are configured to provide a secure attachment to the perimeter around or area adjacent to the umbilical connector face  954  such that no or minimal force transfer to the system is imparted to the joined servicer-client system. In one embodiment, the set of extension guides  886 ,  887  form or are instead a continuous or near-continuous funnel shape (wider in diameter as the shape extends away from the client umbilical connector second end  954 ), the funnel shape engaging with a perimeter around or area adjacent to the umbilical connector face  954  such that no or minimal force transfer to the system is imparted to the joined servicer-client system. 
     The servicer umbilical second end  854  of  FIG.  8    is depicted routing out of the interior of the manipulator arm second end  844  through manipulator arm second end window  846 . The interior of the servicer umbilical is depicted to show bundle of wires  856  held within the servicer umbilical. The number and type of wires in the bundle of wires  856  are a function of, among other things, the functions performed by the umbilical connector as conventionally used during ground operations to communicate with the client. 
       FIG.  9    is flow diagram of a method of use of the operation of the manipulator arm and the servicer umbilical end during precise control operations near the client umbilical connector, as detailed in  FIG.  8   . The method  900  of  FIG.  9    will be described with reference to other figures of the disclosure, in particular  FIGS.  3  and  8   . 
     Generally, the method  900  starts at step  904  and ends at step  940 . Any of the steps, functions, and operations discussed herein can be performed continuously and automatically. In some embodiments, one or more of the steps of the method of use  900 , to include steps of the method  900 , may comprise computer control, use of computer processors, and/or some level of automation. Indeed, most if not all of the steps of method  900  are performed automatically, principally if not entirely by processor  320 . However, in some embodiments some of the steps or parts of some of the steps are performed in concert with or exclusively with human intervention. For example, a human operator may be tasked to confirm a final advance of the servicer umbilical second end at step  928 , to confirm a final rotation of the servicer umbilical second end at step  932 , and/or to confirm a power on electrical energy transfer between servicer and client (e.g. step  728  of method  700 ). 
     The steps are notionally followed in increasing numerical sequence, although, in some embodiments, some steps may be omitted, some steps added, and the steps may follow other than increasing numerical order. A user may interact or perform one or more of the described steps be using a display/GUI. 
     After starting at step  904 , the method  900  proceeds to step  908 . At step  908 , the manipulator arm  140  maneuvers the attached servicer umbilical  150  to a position adjacent or near the client umbilical connector  40 . The processor  360  may operate in a first positioning control mode during step  908 . Step  908  is similar to step  716  of method  700  and as depicted in  FIG.  6 C . After completion of step  908 , the method  900  continues to step  912 . 
     At step  912 , the precise position control system is activated and/or becomes the dominant control means of the manipulator arm. The precise position control is enabled by, in one embodiment, the one or more sensors  885  and/or the set of extension guides  886 ,  887 , as operated and/or controlled by processor  360 . In one embodiment, the precise position control may only be activated when the manipulator arm second end  844 , with coupled servicer umbilical second end face  882 , is near the umbilical connector face  982  to conserve power dissipated in operating the one or more sensors  885 . After completion of step  912 , the method  900  continues to step  912 . 
     At step  916 , the z axes of the servicer umbilical second end face  882  is substantially aligned with the umbilical connector z axis  956 , as depicted in  FIGS.  8  and  6 D . After completion of step  916 , the method  900  continues to step  924 . 
     At step  924 , an initial physical contact is made between the set of extension guides  886 ,  887  and a surrounding surface of the body  820  of client spacecraft. Upon such contact (as measured by any of several means, to include a force sensor mounted at the distal end of one or both of extension guides  886 ,  887 ), the advancement of the servicer umbilical second end face  882  may be stopped to perform checks such as integrity checks on system operation before proceeding. Also, a human confirmation of a go/no-go for securing a connection may be performed. After completion of step  924 , the method  900  continues to step  928 . 
     At step  928 , the servicer umbilical second end face  882  is advanced along z axis  956  toward the umbilical connector face  982 . During advancement, the set of extension guides  886 ,  887  may retract completely or partially so as to disconnect from physical contact with the body  820  of client, or may retract in a telescoping manner or otherwise so as not to prevent or restrict advancement of the servicer umbilical second end face  882 . After completion of step  928 , the method  900  continues to step  932 . 
     At step  932 , with aid of the one or more sensors  885  as controlled by the processor  360 , the servicer umbilical second end face  882  is rotated to align with the umbilical connector face  982 . More specifically, a rotation of the servicer umbilical second end face  882  is performed so as to align the set of three closing extensions  891 ,  892 , and  893  with respective clocking divots  991 ,  992 , and  993 , align the pair of pins  897  and  898  with respective pin receiver divots  997  and  998 , and to align rectangular pin plug  895  with rectangular pin port  995 . Such a rotational alignment aligns the servicer umbilical second end face  882  with the umbilical connector face  982  such that servicer umbilical second end face angle γ is substantially if not completely zeroed out. After completion of step  932 , the method  900  continues to step  936 . 
     At step  936 , the servicer umbilical second end face  882  undergoes final advance along z axis  956  to form a connection with the umbilical connector face  982 . After completion of step  936 , the method  900  ends at step  940 . 
     The exemplary systems and methods of this disclosure have been described in relation to systems and methods of use of providing in-orbit servicing to a spacecraft, such as a satellite. Other uses or applications to the disclosed systems and methods are possible, such as servicing of space telescopes, space stations, etc. Also, to avoid unnecessarily obscuring the present disclosure, the preceding description omits a number of known structures and devices, and other application and embodiments. This omission is not to be construed as a limitation of the scopes of the claims. Specific details are set forth to provide an understanding of the present disclosure. It should however be appreciated that the present disclosure may be practiced in a variety of ways beyond the specific detail set forth herein. 
     Furthermore, it should be appreciated that the various links connecting the elements can be wired or wireless links, or any combination thereof, or any other known or later developed element(s) that is capable of supplying and/or communicating data to and from the connected elements. These wired or wireless links can also be secure links and may be capable of communicating encrypted information. Transmission media used as links, for example, can be any suitable carrier for electrical signals, including coaxial cables, copper wire and fiber optics, and may take the form of acoustic or light waves, such as those generated during radio-wave and infra-red data communications. 
     Also, while the methods have been discussed and illustrated in relation to a particular sequence of events, it should be appreciated that changes, additions, and omissions to this sequence can occur without materially affecting the operation of the disclosed embodiments, configuration, and aspects. 
     A number of variations and modifications of the disclosure can be used. It would be possible to provide for some features of the disclosure without providing others. 
     Although the present disclosure describes components and functions implemented in the aspects, embodiments, and/or configurations with reference to particular standards and protocols, the aspects, embodiments, and/or configurations are not limited to such standards and protocols. Other similar standards and protocols not mentioned herein are in existence and are considered to be included in the present disclosure. Moreover, the standards and protocols mentioned herein, and other similar standards and protocols not mentioned herein are periodically superseded by faster or more effective equivalents having essentially the same functions. Such replacement standards and protocols having the same functions are considered equivalents included in the present disclosure. 
     The present disclosure, in various aspects, embodiments, and/or configurations, includes components, methods, processes, systems and/or apparatus substantially as depicted and described herein, including various aspects, embodiments, configurations embodiments, sub-combinations, and/or subsets thereof. Those of skill in the art will understand how to make and use the disclosed aspects, embodiments, and/or configurations after understanding the present disclosure. The present disclosure, in various aspects, embodiments, and/or configurations, includes providing devices and processes in the absence of items not depicted and/or described herein or in various aspects, embodiments, and/or configurations hereof, including in the absence of such items as may have been used in previous devices or processes, e.g., for improving performance, achieving ease and/or reducing cost of implementation. 
     The foregoing discussion has been presented for purposes of illustration and description. The foregoing is not intended to limit the disclosure to the form or forms disclosed herein. In the foregoing Detailed Description for example, various features of the disclosure are grouped together in one or more aspects, embodiments, and/or configurations for the purpose of streamlining the disclosure. The features of the aspects, embodiments, and/or configurations of the disclosure may be combined in alternate aspects, embodiments, and/or configurations other than those discussed above. This method of disclosure is not to be interpreted as reflecting an intention that the claims require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed aspect, embodiment, and/or configuration. Thus, the following claims are hereby incorporated into this Detailed Description, with each claim standing on its own as a separate preferred embodiment of the disclosure. 
     Moreover, though the description has included description of one or more aspects, embodiments, and/or configurations and certain variations and modifications, other variations, combinations, and modifications are within the scope of the disclosure, e.g., as may be within the skill and knowledge of those in the art, after understanding the present disclosure. It is intended to obtain rights which include alternative aspects, embodiments, and/or configurations to the extent permitted, including alternate, interchangeable and/or equivalent structures, functions, ranges or steps to those claimed, whether or not such alternate, interchangeable and/or equivalent structures, functions, ranges or steps are disclosed herein, and without intending to publicly dedicate any patentable subject matter.