RU2795894C1 - Serving satellite for orbital services using variable engine control - Google Patents

Abstract

FIELD: space technology.

SUBSTANCE: serving satellite for providing position keeping services to the main satellite has a body and a gripping mechanism. The gripping mechanism is configured to be attached to the docking ring to form a connection between the main satellite and the serving satellite. Attaching the gripping mechanism to the docking ring forms a connected unit having a common centre of mass. The serving satellite has at least two motors and at least one controller. Said controller maintains the coupled unit in stationary orbit by selectively orienting two said motors so that thrust vectors of said two motors do not pass through a joint centre of mass, and each of them is offset from a joint centre of mass.

EFFECT: possibility of ensuring extension of service life of the main satellite is achieved.

19 cl, 16 dwg

Description

BACKGROUND OF THE INVENTION

[001] The commercial and government sectors of the space industry face the high costs of launching and maintaining communications and other satellites in Earth's orbit. The lifetime of a satellite is usually determined by the amount of fuel on board the satellite. Even when the on-board electronics are still functional, when the fuel runs out, the satellite usually becomes useless. As the demand for satellite communications increases over time, so does the typical size of satellites. Launching a large geostationary communications satellite requires a significant initial capital investment. The initial capital investment for a satellite service provider includes not only the cost of the satellite itself, but also the cost of launching the aircraft required to carry the satellite from Earth to a launch orbit.

[002] The satellite typically includes its own propulsion system, which allows the satellite to self-transition from the launch orbit to the final geostationary orbit and maintain its orbital position for a period of time up to 15 years. Propulsion technologies have reached their full development over the years and allow the satellite to use not only chemical plants, but also electric propulsion systems, which are much more efficient. This increased efficiency allows fuel savings, which in turn allows larger and/or heavier satellites to be placed into orbit.

[003] A satellite in geostationary Earth orbit is subject to the forces of attraction from the Earth and the Sun, which tend to move the satellite from its desired geostationary position. The satellite relies on its propulsion system to take corrective action to compensate for the shifts caused by the gravitational forces of the Earth and the Sun. The propulsion maneuvers required to maintain the geostationary position of a satellite are sometimes referred to as position maintenance. When a satellite runs out of all onboard fuel, it can no longer use its propulsion system to maintain its geostationary position and may need to be replaced.

[004] In some cases, the satellite launch vehicle may not fully perform its functions and may deliver the satellite into the wrong orbit. The satellite then has to expend its onboard fuel to move itself from the wrong orbit to its correct orbit. Thus, some of the position-keeping fuel may be used for initial orbit correction, which in turn may result in a shorter satellite lifetime, resulting in lower revenue for the satellite service provider. In other cases, a satellite may need to change its orbital position and/or orientation for various commercial or operational purposes. These changes may also require the satellite to consume onboard fuel, resulting in a shorter lifetime.

[005] Due to the high costs associated with replacing a satellite in space, there is a need for technology that can help extend the life of a satellite already in orbit.

SUMMARY OF THE INVENTION

[006] In one aspect, the present disclosure is directed to a serving satellite to provide position keeping services to a primary satellite. The serving satellite may include a body and a gripping mechanism attached to the body. The gripping mechanism may be configured to be attached to a docking ring extending from the outer surface of the main satellite. Attaching the pickup mechanism to the docking ring can form a connection between the main satellite and the serving satellite through the outwardly extending docking ring, resulting in a connected unit having a common center of mass. The serving satellite may include at least two engines and at least one controller. Such a controller may be configured to maintain the coupled unit in a substantially stationary orbit, and may do so by selectively moving each of said at least two motors into angular orientations such that during engine firing, the thrust vectors of each of said at least the two engines did not pass through the joint center of mass, and each of them was offset from the joint center of mass.

[007] In another aspect, the method of maintaining position may include the step of launching a serving satellite into space and the step of maneuvering it to within the docking distance of the main satellite. The method may also include the step of connecting the serving satellite to the main satellite to form a connected unit by engaging at least two arms of the serving satellite with the external docking ring of the main satellite. The connected block may have a common center of mass. The method may include the step of selectively moving each of the at least two engines of the serving satellite to be activated during maneuvers to maintain position, so that the thrust vectors of said at least two engines do not pass through a joint center of mass and are offset from the joint center. mass.

[008] Additional objects and advantages of the embodiments of the present disclosure will be set forth in part in the description which follows, and in part will be apparent from the description, or may be learned by practice of the embodiments of the present disclosure. It is to be understood that both the foregoing general description and the following detailed description are merely illustrative and not restrictive of the disclosed embodiments and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[009] The accompanying drawings, which are included in and form a part of this disclosure, show illustrative disclosed embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure. In drawings:

[010] FIG. 1A shows a plan view of an exemplary serving satellite in accordance with the disclosed embodiments;

[011] FIG. 1B shows a side view of the exemplary serving satellite of FIG. 1A corresponding to the disclosed embodiments;

[012] FIG. 2 shows a plan view of the exemplary engine deployment mechanism of the serving satellite shown in FIG. 2A corresponding to the disclosed embodiments;

[013] FIG. 3 shows an exemplary connected unit or tandem module of the serving satellite of FIG. 1A and 1B and the main satellite corresponding to the disclosed embodiments.

[014] FIG. 4A shows the tandem module with an exemplary orientation of the serving satellite thrusters of FIG. 1A and 1B corresponding to the disclosed embodiments.

[015] FIG. 4B shows a tandem module with another exemplary serving satellite engine orientation of FIG. 1A and 1B corresponding to the disclosed embodiments.

[016] FIG. 5A shows an end view of an exemplary connected block configuration of FIG. 3 along the z-axis of coordinates corresponding to the disclosed embodiments.

[017] FIG. 5B shows a side view of an exemplary connected block configuration of FIG. 3 along the y-coordinates corresponding to the disclosed embodiments.

[018] FIG. 5C shows a plan view of an exemplary connected block configuration of FIG. 3 along the x coordinate axis corresponding to the disclosed embodiments.

[019] FIG. 6A shows the tandem module with an exemplary orientation of the serving satellite thrusters of FIG. 1A and 1B corresponding to the disclosed embodiments.

[020] FIG. 6B shows a tandem module with another exemplary serving satellite thruster orientation of FIG. 1A and 1B corresponding to the disclosed embodiments.

[021] FIG. 7A shows the tandem module with yet another exemplary serving satellite thruster orientation of FIG. 1A and 1B corresponding to the disclosed embodiments.

[022] FIG. 7B shows the tandem module with an additional illustrative orientation of the serving satellite thrusters of FIG. 1A and 1B corresponding to the disclosed embodiments.

[023] FIG. 8 shows the steps of an exemplary method performed using the serving satellite of FIG. 1A and 1B corresponding to the disclosed embodiments.

[024] FIG. 9 shows the steps of an exemplary method performed by the serving satellite of FIG. 1A and 1B corresponding to the disclosed embodiments.

[025] FIG. 10 shows the steps of an exemplary method performed by the serving satellite of FIG. 1A and 1B corresponding to the disclosed embodiments.

DETAILED DESCRIPTION

[026] Aspects of the present disclosure relate to a serving satellite to provide position-keeping services to a primary satellite. The term "satellite" refers, in general, to a spacecraft that can be launched into space and capable of orbiting a planetary body. As an example, a satellite may be capable of orbiting the Earth. The term "primary satellite" refers, in general, to a spacecraft that is already in space in orbit of a planetary body. In some exemplary embodiments, the primary satellite may be located in geostationary Earth orbit. The term "serving satellite" refers to a satellite or spacecraft capable of providing services to the main satellite while the main satellite and the serving satellite are orbiting a planetary body. By way of example, such orbital services provided by a serving satellite to a primary satellite may include orbit recovery, position maintenance, repositioning, inclination change, deorbiting, orbital repositioning, refueling, or any other maneuver or action to repair, moving, or extending the life of the main satellite.

[027] While the present disclosure provides exemplary serving satellite configurations, it should be noted that aspects of the present disclosure in its broadest sense are not limited to the disclosed configurations. On the contrary, it is contemplated that the above principles can be applied to other serving satellite configurations. Fig. 1A shows a front view of an exemplary embodiment of a serving satellite 10 according to the present disclosure. Fig. 1B shows a side view of an exemplary deployed serving satellite 10.

[028] According to the present disclosure, a serving satellite may provide position maintenance services to a primary satellite. As discussed above, the primary satellite may be subject to the gravitational forces of the Earth and/or the Sun, which may cause the primary satellite to move from its assigned position in the geostationary orbit. The serving satellite can help compensate for such offsets by maintaining the primary satellite in its assigned position in the geostationary orbit. The term "position maintenance" may generally refer to the maneuvers associated with providing compensatory offsets required to maintain the primary satellite in its allocated position in the geostationary orbit.

[029] In some exemplary embodiments, the primary satellite may have a docking ring extending from the outer surface of the primary satellite. The term "docking ring" refers, in general, to the structure attached to the outer surface of the main satellite. The docking ring can be used to attach the primary satellite to an aircraft carrier or launch vehicle to launch the primary satellite into space. Alternatively, the docking ring may also be referred to as a payload attachment ring, indicating that it can be used to attach a primary satellite as a payload to a carrier aircraft. The docking ring may be attached to the outer (or outer) surface of the main satellite. In some illustrative embodiments, the docking ring may have a generally circular shape. However, it is contemplated that the docking ring may be of any shape, such as elliptical, polygonal, square, rectangular, or any other shape known in the art. As an example, as shown in FIG. 3, the main satellite 200 may have a docking ring 202.

[030] A serving satellite according to the present disclosure may include a body. The term "body" may refer, in general, to a shell or hull that encloses one or more components of a serving satellite. For example, the body may enclose and surround electronic circuitry for controlling various components of the serving satellite, communications circuitry, fuel tanks that may contain the fuel required to propel the serving satellite, reaction wheels for storing residual serving satellite angular momentum, a plurality of sensors, including sensors for determining accelerations and torques on the serving satellite, and any other satellite components known in the art. In some illustrative embodiments, the body of the serving satellite may form a substantially closed shell. In other illustrative embodiments, one or more side walls of the body may have openings. The body of the serving satellite may be of any shape. For example, the body of the serving satellite may be cubic, cuboid, cylindrical, polygonal, or may have any other shape known in the art. Fig. 1A and 1B, for example, show the generally cuboid body 12 of the serving satellite 10.

[031] The serving satellite of the present disclosure may also include a gripping mechanism attached to the body. The gripping mechanism may be configured to be attached to a docking ring extending from the outer surface of the main satellite. The term "engaging mechanism" refers, in general, to one or more structural elements associated with the serving satellite, which are capable of being mechanically attached or attached to the main satellite. According to the present disclosure, the gripping mechanism may be implemented using a variety of alternative designs. For example, the gripping mechanism may include one or more arms attached to one end of the serving satellite's body. The free end of the lever may include a clamping device configured to receive a portion of the main satellite between the opposing clamping elements. In one exemplary embodiment according to the present disclosure, a primary satellite docking ring may be received between the opposing clamp members of the clamp device. The opposing clamp elements may be configured to sandwich the mating ring between the opposing clamp elements.

[032] In another illustrative embodiment of the gripping mechanism, the free end of the arm may include radially extending structural elements that may engage the inner surface of the docking ring at one or more locations. The radially outward force exerted by the radially extending elements on the docking ring may serve to attach the arm to the docking ring. While the present disclosure describes various examples of a gripping mechanism, the present disclosure in its broadest sense is not limited to a particular configuration or design of the gripping mechanism. On the contrary, it is contemplated that any design or configuration capable of forming a reliable connection to a primary satellite can be considered a "capture mechanism" within the meaning of this disclosure. Fig. 1A and 1B show an exemplary embodiment of the gripping mechanism 14.

[033] Thus, a gripping mechanism according to the present disclosure may include at least two levers, which, for example, may be configured to engage with a docking ring. The term "arm", which may also be referred to as a "docking arm", may include one or more structural elements extending outward from the body of the serving satellite. Each arm may have one or more points of articulation or articulating knees. It is contemplated that, in some exemplary embodiments, a serving satellite may include more than two arms. Fig. 1A shows an exemplary embodiment of a serving satellite 10 that may include four docking arms 16. As shown in FIG. 1B, each docking lever 16 may include a four-bar linkage. It should be noted, however, that the docking lever according to the present disclosure is not limited to the disclosed four-bar lever configuration. On the contrary, it is contemplated that docking lever 16 may include a two-rod, three-rod, or six-rod link mechanism. In some exemplary embodiments according to the present disclosure, docking arm 16 may include any number of connections. It is also contemplated that in some embodiments, no connections will be used.

[034] In the exemplary embodiment of serving satellite 10 shown in FIG. 1B, the docking arm 16 may include a stationary leg 18 attached to the body 12 of the serving satellite 10. As also shown in FIG. 1B, docking arm 16 may include two legs 20, 22 spaced apart and rotatably connected to stationary leg 18 at hinges 24 and 26, respectively. The rotation of each of the legs 20 and 22 about the hinges 24 and 26, respectively, can be independently controlled to move the docking arm 16. It is also contemplated that in some illustrative embodiments, a body part 12 of the serving satellite 10 can replace the stationary leg 18 of the four-bar linkage. Thus, for example, the legs 20, 22 may be spaced apart and rotatably connected to the body 12 of the serving satellite 10 via hinges 24, 26, respectively.

[035] In the illustrative embodiment of the docking arm 16 shown in FIG. 1B, the operating arm 28 may be pivotally connected at one end 30 to one of the two elbows (eg, elbow 20), while the other of the two limbs (eg, elbow 22) may be connected to the operating arm 28 between the attached end 30. and a free end 32. The free end 32 of the operating arm 28 may include a ring-engaging portion 34 configured to engage with the main satellite's docking ring. The ring engaging portion 34 may include one or more of the clamping mechanisms described above. While the present disclosure describes serving satellite 10 having four docking arms 16, it is contemplated that serving satellite 10 may include any number of docking arms 16.

[036] Additionally, although the present disclosure describes attaching the docking arm to the docking ring of the main satellite, the present disclosure in its broadest sense is not limited to a specific method of attachment. It is contemplated that the free end of the gripping mechanism may be configured to be attached to an external structural element of the main satellite other than the docking ring. For example, the free end of the gripping mechanism may be configured to be attached to a protrusion or other structural element located on the outer surface of the main satellite.

[037] According to the present disclosure, by attaching to the docking ring, the grabbing mechanism can form a connection between the main satellite and the serving satellite through the docking ring extending outward. The term "connection" refers, in general, to an attachment, attachment, or connection between two objects. The connection between the serving satellite and the main satellite according to the present disclosure may be rigid enough to be able to transfer driving forces from the serving satellite to the main satellite, or vice versa. Fig. 3, for example, shows a connection 204 between serving satellite 10 and main satellite 200.

[038] According to the present disclosure, attaching a serving satellite capture mechanism to a host satellite can result in a connected unit having a common center of mass. The term "connected block" refers, in general, to a module formed by attaching, attaching, or linking two objects. For example, attaching a serving satellite capture mechanism to a main satellite may form a connected unit or module that includes a serving satellite and a main satellite. In some illustrative embodiments, the connected unit formed by connecting the serving satellite and the main satellite may also be referred to as a "tandem module". Fig. 3, for example, shows a coupled block 206 formed by attaching a gripping mechanism 14 of a serving satellite 10 to a docking ring 202 of a main satellite 200. It should be noted that a coupled block 206 may be formed by attaching some or all of the docking arms 16 of a serving satellite 10 to a main satellite. 200. Exemplary embodiments of the gripping mechanism of the present disclosure are disclosed in International Patent Application No. PCT/IL2015/050856, filed August 26, 2015, and U.S. Provisional Application No. 62/041,780, filed August 26, 2014, both of which are included in their entirety. link to this document.

[039] The term "joint center of mass" refers, in general, to the center of mass of two objects connected to each other. The joint center of mass of the connected unit formed by the serving satellite and the main satellite may depend on, for example, the mass of the serving satellite and the mass of the main satellite. The joint center of mass may also depend, for example, on how the mass of the serving satellite and the mass of the main satellite are distributed in space. It should be noted that the connected unit, including the serving satellite and the main satellite, will necessarily have a joint center of mass.

[040] A serving satellite according to the present disclosure may include at least two engines. As used here, a motor generally refers to a device that can provide a driving force to move an object to which the motor can be attached. In some exemplary embodiments, the engine may cause fuel to flow out of the engine in a generally predetermined direction, thereby generating a driving force in a direction opposite to the predetermined direction. The fuel used by the engine may be in liquid or gaseous form. The engine, according to various embodiments of the present disclosure, can be a chemical engine, a resistor jet engine, a cold gas engine, an electric traction engine, a dual propellant engine, a Hall effect engine, a grid ion engine, an electric arc engine, a plasma traction engine, or any other type of motor known in the art, or which may be used to propel an object through space.

[041] According to embodiments of the present disclosure, said at least two motors may include a first pair of motors and a second pair of motors. When used here, the term "pair" means two engines. It should be noted, however, that the phrase "pair of motors" in the present disclosure is not limited to two motors that may be coupled to each other mechanically, electrically, or in any other manner. For example, the first pair of motors and the second pair of motors may collectively include four separate and independently controllable motors. While the present disclosure describes certain engine configurations and positions, the present disclosure in its broadest sense is not limited to specific engine configurations and positions. Thus, for example, it is contemplated that in some exemplary embodiments, the serving satellite may have an odd number of engines. It is further contemplated that, in other embodiments, a serving satellite of the present disclosure may have more than two engine pairs.

[042] According to embodiments of the present disclosure, said at least two engines may include a first north engine and a second north engine. The first north engine and the second north engine may be located on the first side of the serving satellite. The first north engine may be located at a distance from the second north engine. According to some embodiments of the present disclosure, the at least two engines may also include a first south engine and a second south engine. The first south engine and the second south engine may be located opposite the first side of the serving satellite. The first south engine may be located at a distance from the second south engine. The terms "northern" and "south" in their broadest sense are not limited to a specific position relative to the serving satellite. On the contrary, in its broadest sense, the terms "north" and "south" mean opposite sides of the serving satellite. The opposite sides may be located on either of the two sides of the coordinate plane passing through the body of the serving satellite.

[043] FIG. 1A shows an exemplary embodiment of a serving satellite 10 having engines 36, 38, 40, and 42. As shown in FIG. 1A, motors 36 and 38 may be located on the first side 44 of the body 12 of the serving satellite 10. For example, motors 36 and 38 may be located on the first side 44 of the plane 46 passing through the body 12. The motors 36 and 38 may be located at a distance of each from friend. In some exemplary embodiments, plane 46 may define the generally longitudinal plane of symmetry of the serving satellite 10. In other exemplary embodiments, plane 46 may define the zenith-nadir plane of the serving satellite relative to the Earth. As also shown in the illustrative embodiment of FIG. 1A, motors 40 and 42 may be located on second side 48 of body 12 of serving satellite 10. For example, motors 40 and 42 may be located on second side 48 of plane 46. Second side 48 of body 12 may be opposite first side 44.

[044] In the exemplary embodiment shown in FIG. 1A, first side 44 may be identified as the north side of serving satellite 10, and second side 48 may be identified as south side of serving satellite 10. Motors 36 and 38 may be referred to as first north thruster 36 and second north thruster 38. Similarly, thrusters 40 and 42 may be referred to as first south thruster 40 and second south thruster 42. It should be noted that in some embodiments, side 44 may be referred to as the south side and side 48 may be referred to as the north side of serving satellite 10. In these In exemplary embodiments, motors 36 and 38 may be referred to as first south motor 36 and second south motor 38, and motors 40 and 42 may be referred to as first north motor 40 and second north motor 42.

[045] According to some aspects of the present disclosure, the first pair of engines may include a first north engine and a first south engine. Similarly, the second pair of engines may include a second north engine and a second south engine. Fig. 1A, for example, shows a first engine pair 54 including engine 36 and engine 40, and a second engine pair 56 including engine 38 and engine 42. In one exemplary embodiment, when first side 44 is designated north side, and the second side 48 is designated as the south side of the serving satellite 10, the first pair of engines 54 may include the first north engine 36 and the first south engine 40. Similarly, the second pair of engines 56 may include the second north engine 38 and the second south engine 42.

[046] In some illustrative embodiment shown in FIG. 1A, third side 58 may be identified as the east side of serving satellite 10 and fourth side 60 may be identified as west side of serving satellite 10. Third side 58 and fourth side 60 may be located on opposite sides of a plane 62 passing through the body 12 of the serving satellite 10. Plane 62 may be located generally perpendicular to plane 46. In some aspects of the present disclosure, plane 62 may be a plane of symmetry of serving satellite 10. Motors 36 and 40 may be referred to as first easter 36 and second easter 40, which may be located at a distance from each other, and may be located on the third side 58 of the serving satellite 10. Similarly, the engines 38 and 42 can be referred to as the first west engine 38 and the second west engine 42, which can be located at a distance of each other. apart and may be located on the fourth side 60 of the serving satellite 10, opposite the third side 58. It should be noted, however, that in some embodiments, side 58 may be designated as the west side and side 60 may be designated as the east side of the serving satellite. 10. In these exemplary embodiments, engines 36 and 40 may be designated first west engine 36 and second west engine 40, and engines 38 and 42 may be designated first east engine 38 and second east engine 42.

[047] According to the present disclosure, a serving satellite may include an engine deployment mechanism. The term "engine deployment mechanism" refers generally to one or more structural members attached to a serving satellite and capable of extending outward and away from the body of the serving satellite. The engine deployment mechanism may include various alternative designs as long as these designs are capable of deploying the engine. In some exemplary embodiments according to the present disclosure, each engine may have a dedicated engine deployment mechanism. For example, each motor may be attached to an extension or boom, which may have a first end attached to the body of the serving satellite and a free end distal to the first end. The motor can be attached to the free end of an extension or boom. In other exemplary embodiments according to the present disclosure, more than one motor may be attached to the same jib or boom. In other exemplary embodiments, the thruster deployment mechanism may include one or more linkage mechanisms capable of positioning the thrusters at a predetermined distance from the body of the serving satellite. For example, the motor deployment mechanism may include two-, four-, or six-bar linkages, similar to those of the pickup mechanism described above.

[048] FIG. 1A, for example, shows the engine deployment mechanism 64 of the serving satellite 10. The engine deployment mechanism 64 may include engine deployment forks 66 (see FIG. 1A). As shown in FIG. 2, the motor deployment fork 66 may include a fork base 70 and fork arms 72, 74. The base 70 of the plug can be pivotally connected to the body 12 of the serving satellite 10 at the end 76 of the base of the plug. The fork arms 72, 74 may extend from the fork base 70 to the fork arm ends 78, 80, respectively. The ends 78, 80 of the fork arms can be spaced apart. In one illustrative embodiment, shown in FIG. 2A and 2B, the yoke base 70 and the yoke arms 72, 74 may form a generally "Y" shaped structure. Although not shown in FIG. 2, the engine yoke 68 (see FIG. 1A) may be of a construction similar to that described above with respect to the engine yoke 66. The fork base 70 and fork arms 72, 74 may define fork planes 86, 88 (see FIG. 1B). Although FIG. 2A and 2B show that each of the engine deployment forks 66, 68 has only two fork arms 72, 74, it is contemplated that the engine deployment forks 66, 68 may have any number of fork arms. Additionally, although FIG. 1A and 1B show that serving satellite 10 has only two engine forks 66, 68, it is contemplated that serving satellite 10 may have any number of engine forks.

[049] Returning to FIG. 1B, the motor yokes 66, 68 can be oriented in a given orientation by rotating the motor yokes 66, 68 about plane 46 (see FIG. 1A). In one illustrative embodiment, shown in FIG. 1B, the orientation of the motor yokes 66, 68 may be determined by the angle ϕ between the fork planes 86, 88, respectively, and planes parallel to the plane 46 of the serving satellite 10. It is contemplated that the motor yokes 66, 68 may be oriented under the same or different angles ϕ relative to the plane 46.

[050] According to the present disclosure, a serving satellite engine deployment mechanism may also include one or more engine positioning devices. When used here, the engine positioning device may include a structural element connected to the engine deployment yoke, capable of changing the orientation of the engine. This may be through mechanisms that turn, tilt, rotate, or otherwise redirect the motor. The engine may be attached to such a structural element. While the present disclosure describes a configuration having an engine positioning device attached to the engine deployment yoke, the present disclosure is not limited in its broadest sense to the disclosed configuration. For example, it is contemplated that the engine positioner can be directly attached to the body of the serving satellite. It is also contemplated that more than one motor may be attached to each motor positioner. It is further contemplated that the serving satellite may have any number of engine positioners.

[051] FIG. 1A shows exemplary motor positioners implemented in this particular example as motor arms 90, 92, 94, 96. As shown in FIG. 1A, for example, engine arm 90 may include first end 98 and second end 100. First end 98 of engine arm 90 may be rotatably attached to arm end 78 of engine deployment yoke 66. The motor 36 may be fixedly attached to the second end 100 of the arm 90 of the motor. As also shown in FIG. 1A, for example, engine arm 92 may include first end 102 and second end 104. First end 102 of engine arm 92 may be rotatably attached to fork arm end 80 of first engine deployment fork 66. The motor 38 may be fixedly attached to the second end 104 of the arm 92 of the motor.

[052] As further shown in FIG. 1A, for example, engine arm 94 may include first end 106 and second end 108. First end 106 of engine arm 94 may be rotatably attached to arm end 82 of engine deployment yoke 68. The motor 40 may be fixedly attached to the second end 108 of the arm 94 of the motor. Additionally, as shown in FIG. 1A, for example, engine arm 96 may include first end 110 and second end 112. First end 110 of engine arm 96 may be rotatably attached to arm end 84 of engine deployment yoke 68. The motor 42 may be fixedly attached to the second end 112 of the arm 96 of the motor.

[053] According to some embodiments of the present disclosure, the orientation of the engine attached to the engine arm can be determined by the angular displacement Θ between the engine arm and the engine yoke plane to which the engine arm can be attached. Thus, for example, as shown in FIG. 1B, the orientation of the motor 36 can be determined by the angular displacement Θ ₁ between the motor arm 90 and the motor yoke 66. The angular displacement Θ ₁ of the motor arm 90 may determine the first position P1. Any of the motors 36, 38, 40, and 42 can be oriented to position P1 by establishing an angular displacement Θ ₁ between the respective motor arm and the motor yoke. It is also contemplated that the motors 36, 38, 40, 42 may be oriented with the same or different values of angular displacement Θ. While the present disclosure describes a configuration in which the orientation of an engine is determined by an angular displacement Θ between an engine arm and its respective engine yoke, the present disclosure is not limited in its broadest sense to the disclosed configuration. For example, it is contemplated that the orientation of the motors 36, 38, 38, 40 can be determined by the angular displacements of the motor arms 90, 92, 94, 96, respectively, with respect to plane 46. In other illustrative embodiments, the orientation of the motors 36, 38, 38, 40 can be determined by the angular displacements of the motor arms 90, 92, 94, 96, respectively, relative to the plane 58. In other exemplary embodiments, the orientation of the motors 36, 38, 38, 40 may be determined by the angular displacements of the motor arms 90, 92, 94, 96 relative to any other surface of the body 12 of the serving satellite 10.

[054] According to the present disclosure, a serving satellite may include at least one controller. As used herein, the term "controller" refers to electrical or other elements capable of controlling the various operations of a serving satellite. For example, at least one controller may include a device that has appropriate logic or computing components configured according to the requirements of a particular application. In some embodiments, the controller may include any physical device having an electrical circuit that performs a logical operation on an input signal or input signals. For example, said at least one controller may include a processor that has one or more integrated circuits, microcircuits, microcontrollers, microprocessors, all or part of the central processing unit (central processing unit - CPU), graphic processor (graphics processing unit - GPU) , a digital signal processor (DSP), a field-programmable gate array (FPGA), or other circuits suitable for executing instructions or performing logic operations. The instructions executed by the controller may, for example, be pre-loaded into a memory device integrated with or built into the controller, or may be stored in a separate memory device such as Random Access Memory (RAM), Read Only Memory (Read-Only Memory - ROM), hard disk, optical disk, magnetic storage medium, flash memory, other read-only, non-volatile, or non-volatile memory, or any other mechanism capable of storing instructions for the controller. Said one or more controllers may include single or multi-core processors based on RISC, CISC, or any other computer instruction architecture.

[055] In the case of using more than one controller or processor, they may all have a similar design, or they may have different designs, electrically connected or not connected to each other. They may be separate circuits or may be combined into a single circuit. When using more than one controller or processor, they can work independently or together. They may be connected electrically, magnetically, optically, acoustically, mechanically, or by other means allowing them to interact. In some embodiments, said at least one processor may be associated with memory.

[056] The storage devices associated with the controller or processor may include, for example, non-OR or non-AND type flash memory devices, Read Only Memory (ROM), memory devices with random access (Random Access Memory - RAM), etc. Storage devices associated with the controller may include, for example, hard disk drives, solid state drives, etc.

[057] Said at least one controller, when deployed in orbit, may also be configured to communicate with one or more controllers located at a ground control station on Earth via one or more telecommunications interfaces and other telecommunications circuits. Fig. 1A and 1B, for example, show an exemplary controller 120.

[058] In some aspects of the present disclosure, the controller may be located on board the serving satellite. In other aspects, the controller may be located at a ground control station on Earth. In other aspects of the present disclosure, the controller may be located on board a spacecraft other than a serving satellite. When the controller is not located on board the serving satellite, the controller may be able to control various operations of the serving satellite based on signals transmitted from the serving satellite controller through one or more telecommunications interfaces or other telecommunications circuits.

[059] According to the present disclosure, said at least one controller may be configured to maintain the connected unit in a substantially stationary orbit. When used here, the term "stationary orbit" refers to the geostationary orbit of the Earth. The primary satellite in geostationary orbit may have a dedicated area. The selected area may be defined by a first predetermined distance in an east-west direction (ie, along the geostationary orbit), and a second predetermined distance in a north-south direction (ie, perpendicular to the geostationary orbit). Due to the influence of the forces of gravity of the Earth and the Sun on the connected block, the connected block can move relative to its position in the geostationary orbit. The engines of the serving satellite, the main satellite, or both, may be activated to counteract the gravity forces of the Earth and the Sun causing the coupled block to move to move the main satellite within the selected area. Thus, as used herein, the phrase "substantially stationary orbit" may encompass movements of the connected unit in and around the allocated area in geostationary orbit.

[060] Said at least one controller can maintain the connected unit in a substantially geostationary orbit by selectively moving each of said at least two engines in angular orientations so that during engine activation, the thrust vectors of each of said at least two engines did not pass through the center of mass. In some exemplary embodiments, the controller may cause the engines to be turned on, for example by pushing fuel out of the engines. As discussed above, fuel being pushed out of an engine can generate reactive force on the engine in a direction opposite to the direction in which the fuel is being pushed out. When used here, the term "thrust vector" refers, in General, to the combination of the magnitude of the reactive force and the direction of the reactive force applied to the engine. It should be noted that the reactive force applied to the engine will also be applied to the serving satellite and to the connected unit when the serving satellite is connected to the main satellite. The reactive forces generated by the engines may cause the connected unit to move in the direction corresponding to the vector direction of the sum of the thrust vectors generated by the selected engines.

[061] The serving satellite may be connected to any one of a plurality of primary satellites to form a plurality of connected blocks. Each such connected unit formed by connecting the serving satellite to the main satellite may have a common center of mass.

[062] It is contemplated that according to the present disclosure, the controller may be configured to orient at least two motors such that the thrust vectors of said at least two motors do not pass through any of the joint centers of mass corresponding to the plurality of connected blocks formed by the connection serving satellite with a plurality of primary satellites. Indeed, according to various embodiments of the present disclosure, the thrust vectors of each of said at least two engines may be offset from a common center of mass. When used here, the term "offset" refers, in General, to the spatial separation. Thus, for example, said at least one controller may orient the selected engines such that the thrust vectors of the selected engines can be spatially separated from the joint centers of mass corresponding to the plurality of connected blocks described above. While the present disclosure describes a configuration in which at least two engines are selected, the present invention in its broadest sense is not limited to a particular configuration. For example, it is contemplated that said at least one controller may select one, two, or any number of motors for the maneuver described above. Said at least one controller may be configured to orient one or more selected engines such that the thrust vectors generated by the selected engines do not pass through the common centers of mass corresponding to the plurality of connected blocks described above.

[063] FIG. 4A and 4B show an example of an engine being turned on such that the thrust vectors do not pass through the joint center of mass of the coupled block. For example, as shown in FIG. 4A, the at least one controller 120 can orient the engine arm 90 with an angular displacement _Θ2 relative to the first engine yoke 66. In some embodiments, the angular displacement Θ ₂ may determine the position of P2. As also shown in FIG. 4A, the controller 120 may orient the motor arm 92 with an angular displacement Θ ₃ relative to the first motor yoke 66 . In some embodiments, the angular displacement Θ ₃ may determine the position of P3. Controller 120 may turn on motors 36, 38. On motor 36 may generate thrust vector 122, and on motor 38 may generate thrust vector 124. As shown in the exemplary embodiment of FIG. 4A, thrust vectors 122 and 124 may not pass through a common center of mass 126. It is assumed that due to the fixed orientation of the thrust vectors in FIG. 4A, serving satellite 10 may dock with a plurality of different primary satellites, each of which has a different center of mass, and the joint centers of mass in each case may still lie between thrust vectors 122, 124.

[064] FIG. 4B shows another exemplary embodiment in which the motor arm 90 is oriented at an angular offset Θ ₃ (position P3) and the motor arm 92 is oriented at an angular offset Θ ₂ (position P2). Controller 120 may turn on motors 36, 38. On motor 36 may generate thrust vector 132, and on motor 38 may generate thrust vector 134. As shown in FIG. 4B, thrust vectors 132 and 134 do not pass through a common center of mass 126. It is assumed that due to the fixed orientation of the thrust vectors in FIG. 4A, serving satellite 10 may dock with a plurality of different primary satellites, each having a different center of mass, and the joint centers of mass in each case may still lie between thrust vectors 132, 134.

[065] Embodiments of the present disclosure may further include at least one controller configured to selectively move each of said at least two motors so that the joint center of mass is located between the points of intersection of the thrust vectors and the plane passing through joint center of mass of the connected block. The term "point of intersection" refers to the location where the thrust vector intersects with the plane. In some illustrative embodiments according to the present disclosure, this plane may be a longitudinal plane passing through the connected unit, including the main satellite and the serving satellite. The thrust vectors generated when the engines of the serving satellite are turned on can intersect the longitudinal plane in a variety of positions. Said at least one controller, according to embodiments of the present disclosure, can orient the engines of the serving satellite so that the joint center of mass of the serving satellite and the main satellite can lie between the points of intersection of the thrust vectors with the longitudinal plane.

[066] FIG. 4A, for example, shows a configuration in which engine arms 90, 92 can be oriented with angular displacements Θ ₂ , Θ ₃ , respectively, such that thrust vectors 122 and 124 can intersect plane 62 at positions 128 and 130, respectively. As also shown in the illustrative embodiment of FIG. 4A, positions 128 and 130 may be offset or spaced apart from the joint mass center 126. As further shown in FIG. 4A, the joint center of mass 126 may lie between the intersection positions 128 and 130. Similarly, as shown in the exemplary embodiment of FIG. 4B, engine arms 90, 92 may be oriented with angular displacements Θ ₃ , Θ ₂ , respectively, such that thrust vectors 132 and 134 may intersect plane 62 passing through serving satellite 10 and main satellite 200 at locations 136 and 138, which are displaced (ie, spatially separated) from the joint center 126 mass. As shown in FIG. 4B, joint center of mass 126 may lie between intersection positions 136 and 138.

[067] Returning to FIG. 1A and 1B, in some exemplary embodiments, serving satellite 10 may include one or more solar panels 140 that may be attached to body 12 of serving satellite 10. Solar panels 140 may extend outward from body 12 of serving satellite 10. The solar panels 140 may be configured to be positioned generally perpendicular to the surface 142 of the body 12 (see FIG. 1B). It is contemplated, however, that the solar panels 140 may be tilted relative to the surface 142 of the body 12. The solar panels 140 may generate electrical energy that can be used to perform various operations associated with the serving satellite 10. For example, the energy generated by the solar panels 140 batteries, can be used to turn on the gripping mechanism 14, the motor deployment mechanism 64 (see FIGS. 2A, 2B), the motors 36, 38, 40, 42, the controller 120 and related electrical circuits, etc., when applied to controller 120 and other electrical and telecommunication circuits.

[068] According to embodiments of the present disclosure, said at least one controller may be further configured to adjust the thrust level of each of said at least two engines so that the torques generated by the thrust vectors about at least one coordinate axis of the connected bloc, were essentially balanced. As used here, the term "thrust level" refers to the amount of reactive force generated by the engine. In some exemplary embodiments, the level of thrust may be adjusted by controlling the amount of fuel pushed by the engine over a predetermined amount of time. In other embodiments, the level of thrust may be determined by the rate at which fuel is ejected from the engine. As used herein, the term "torques" refers to the moment of the thrust vector generated by the engine about an axis associated with the serving satellite or the main satellite. This moment can be defined as the product of the thrust level and the length of the perpendicular between the thrust vector and this axis. Also, as used here, the term "balanced" refers to the nulling of torques. Thus, for example, said at least one controller according to the present disclosure may select the thrust levels of said at least two engines such that the torque generated by the thrust vector of one of the two engines is exactly equal to and opposite to the torque generated by the vector thrust of the second of the two engines. The resulting torque resulting from the sum of the generated torques may be essentially zero. It is also contemplated that, in some exemplary embodiments, torque balancing can be achieved based on more than two motors.

[069] FIG. 4A and 4B, for example, show configurations in which the torques can be balanced. Thus, in the exemplary embodiment of FIG. 4A, controller 120 may orient motor arms 90 and 92 with angular displacements _Θ2 (position P2) and _Θ3 (position P3), respectively. Controller 120 may include motors 36, 38 to generate thrust vectors 122, 124, respectively. Each of the thrust vectors 122 and 124 can generate torque about the y-axis coordinates of the serving satellite 10. The action of the torques generated by the thrust vectors 122, 124 in the form of a rotational force acting on the coupled block 206 is shown in FIG. 4A arrow 148.

[070] Similarly, in the exemplary embodiment shown in FIG. 4B, controller 120 may orient motor arms 90 and 92 with angular displacements Θ ₃ (position P3) and Θ ₂ (position P2), respectively. Controller 120 may turn on motors 36 and 38 to generate thrust vectors 132, 134, respectively. Each of the thrust vectors 132 and 134 can generate a torque about the y-axis coordinates of the serving satellite 10. The action of the torques generated by the thrust vectors 132, 134 in the form of a rotational force acting on the coupled block 206 is shown in FIG. 4B by arrow 152. Controller 120 may select the thrust levels of engines 36 and 38 such that the magnitude and direction of torque represented by arrow 148 (FIG. 4A) are exactly equal and opposite to the magnitude and direction of torque represented by arrow 152 (FIG. 4B). In other words, controller 120 can select the thrust levels of engines 36 and 38 such that the sum of the torque vectors represented by arrows 148 and 152 can be substantially zero. It is contemplated that the thrust levels of engines 36 and 38 may be equal or unequal.

[071] FIG. 5A, 5B, and 5C show exemplary configurations in which torques can be balanced about two axes. Fig. 5A shows a view of the connected block 206, with the z-axis of coordinates being generally perpendicular to the frontal flat surface area shown in FIG. 5A. In some exemplary embodiments, as shown in FIG. 5A, the z-axis in this figure may be a longitudinal axis that may extend along the center line of both serving satellite 10 and main satellite 200 forming conjoined block 206. Motors 36 and 38 may be oriented at positions P2 and P3, respectively, similar to the positions shown in Fig. 4A. Controller 120 may select thrust levels for motors 36 and 38 such that the torques generated about the z-axis by thrust vectors 122, 124 can substantially cancel each other out, as shown by two opposing arrows 69 in FIG. 5A.

[072] Similarly, FIG. 5B shows a view of the connected block 206, in which the y-axis of coordinates can be located generally perpendicular to the frontal flat surface area shown in FIG. 5V. The y-axis may also be generally perpendicular to the z-axis. When motors 36 and 38 are at positions P2 and P3 (see FIG. 4A), respectively, thrust vectors 122 and 124 can generate torques about the y-axis. These torques can be represented by the arrow shown in FIG. 5B and may be similar to arrow 148 in FIG. 4A. As will be described below, these torques can generate momentum that can be stored in the reaction wheel. When the positions of motors 36 and 38 are reversed such that motor 36 is in position P3 and motor 38 is in position P2 (see FIG. 4B), the torques generated by thrust vectors 132 and 134, as shown in FIG. 4B can unload the reaction wheel and reduce the stored torque of the reaction wheel, thereby substantially balancing the resulting torques generated about the y-axis.

[073] FIG. 5C shows a view of the connected block 206 in which the x-axis of coordinates may be positioned generally perpendicular to the frontal flat surface portion shown in FIG. 5C. The x-axis may also be generally perpendicular to the y and z axes. Motors 36 and 38 can be oriented to positions P2 and P3, respectively (see FIG. 4A). Controller 120 may select thrust levels for motors 36 and 38 such that the torques generated about the x-axis by thrust vectors 122, 124 can substantially cancel each other out, as shown by two opposing arrows 71 in FIG. 5C.

[074] According to embodiments of the present disclosure, the controller may be configured to turn on said at least two motors at a first thrust level when the first motor is oriented in a first angular orientation. The controller may also be configured to turn on said at least two engines with a second thrust level different from the first thrust level when the first engine is oriented in a second angular orientation. In some exemplary embodiments, the controller may select thrust levels for the motors based on their position and/or orientation. For example, the controller may turn on the engine in position P2 with the first thrust level TH1, and turn on the engine in position P3 with the second thrust level TH2. In other illustrative embodiments, the controller may turn on both of the at least two engines with the first thrust level TH1 when the first engine of the at least two engines is oriented to one of the positions P2 or P3. The controller may turn on both of the at least two engines with the first thrust level TH1 when the first engine of the at least two engines is oriented to the second of the positions P2 or P3. It is contemplated that thrust levels TH1 and TH2 may be equal or unequal.

[075] FIG. 4A and 4B show exemplary embodiments in which controller 120 may be configured to turn on engines 36, 38, 40, 42 with different thrust levels. In the exemplary embodiment of FIG. 4A, controller 120 may orient motor arms 90 and 92 with angular displacements _Θ2 (position P2) and _Θ3 (position P3), respectively. Controller 120 may turn on engines 36 and 38 at thrust level TH1 to generate thrust vectors 122, 124, respectively. Controller 120 may turn on both engines 36 and 38 at thrust level TH1 when engine 36 is oriented to position P2. In the exemplary embodiment of FIG. 4B, controller 120 may orient motor arms 90 and 92 with angular displacements Θ ₃ (position P3) and Θ ₂ (position P2), respectively. Controller 120 may turn on engines 36 and 38 at thrust level TH2 to generate thrust vectors 132, 134, respectively. Controller 120 may turn on both engines 36 and 38 at thrust level TH2 when engine 36 is oriented to position P2.

[076] According to some embodiments of the present disclosure, the controller may be configured to determine a second thrust level. The controller may be configured to do this by turning on said at least two motors at a first thrust level when the first motor is oriented in a first angular orientation. The controller may also be configured to determine an angular momentum with respect to at least one coordinate axis of the connected block. Additionally, the controller may be configured to determine a second thrust level with which said at least two motors should be turned on when the first motor is oriented in the second angular orientation such that angular momentum is substantially reduced to zero. When used here, the term "momentum" refers to the product of the moment of inertia of an object's rotation and its frequency of rotation about the axis of rotation. The controller can determine the angular momentum in many ways. In some illustrative embodiments, the controller may determine the speed or angular velocity of the connected unit based on sensors located in the serving satellite or the main satellite. The controller may also determine the moment of inertia of rotation of the coupled unit based on the mass distributions in the serving satellite and the main satellite. The controller can determine the angular momentum of the coupled block based on the determined rotational speed and rotational inertia. In other exemplary embodiments, momentum may be determined by measurements using a momentum sensor. In other exemplary embodiments, the angular momentum may be determined based on the change in the speed of the reaction wheel associated with the serving satellite or the main satellite.

[077] FIG. 4A and 4B show exemplary embodiments in which the controller may be configured to determine thrust levels based on angular momentum. In the exemplary embodiment of FIG. 4A, controller 120 may orient motor arms 90 and 92 with angular displacements _Θ2 (position P2) and _Θ3 (position P3), respectively. Controller 120 may turn on engines 36 and 38 at thrust level TH1 to generate thrust vectors 122, 124, respectively. Controller 120 may turn on both motors 36 and 38 at thrust level TH1 when motor lever 90 is oriented at an angular displacement Θ ₂ (position P2). The controller 120 may determine the moment AM1 of the connected block 206, including the serving satellite 10 and the main satellite 200, with respect to at least one axis of the serving satellite. Thus, for example, the controller 120 can determine the pulse moment AM1 generated about the y-axis as shown in FIG. 5V. The controller 120 may determine the pulse moment AM1 based on the mass distribution of the serving satellite 10 and the main satellite 200, the angular velocities of the serving satellite 10 and the main satellite 200 about the y-axis, and the distances of the various parts of the serving satellite 10 and the main satellite 200 to the y-axis. In some exemplary embodiments, controller 120 may determine momentum AM1 using one or more momentum sensors located in serving satellite 10 and/or using one or more flywheels located in serving satellite 10.

[078] In the exemplary embodiment of FIG. 4B, controller 120 may orient motor arms 90 and 92 with angular displacements Θ ₃ (position P3) and Θ ₂ (position P2), respectively. The controller 120 may determine the level of thrust TH2 with which the controller 120 should turn on the motors 36 and 38, such that the moment AM2 of the impulse generated about, for example, the y-axis (as shown in Fig. 5B) is exactly equal and opposite to the moment AM1 the pulse generated as described above with respect to the embodiment of FIG. 4A. The controller 120 may turn on both motors 36 and 38 at a thrust level TH2 when the motor arm 90 is oriented at an angular displacement Θ ₃ (position P3) such that the total amount of torque AM1+AM2 is approximately zero.

[079] According to embodiments of the present disclosure, said at least one controller may be configured to, during a first period of time, position a first motor of said at least two motors in a first angular orientation and turn on the first motor. Said at least one controller may also be configured, during a first period of time, to position a second motor of said at least two motors in a second angular orientation different from the first angular orientation and turn on the second motor. The controller can position the motors in many ways, and the present invention, in its broadest sense, is not limited to any particular way. In one method, for example, the controller may position both motors to their relative positions simultaneously or sequentially. The controller may also turn on both motors simultaneously or in series. In some exemplary embodiments, the controller may position the first motor to the first position and turn on the first motor for a first on duration, which may be less than a first period of time. After turning on the first motor during the first on duration, the controller may position the second motor to the second position and turn on the second motor during the second on duration. In other exemplary embodiments, the controller may position both the first and second motors to their respective first and second positions. After positioning both motors, the controller may turn on the first and second motors simultaneously for their respective first and second duty cycles.

[080] FIG. 4A shows an exemplary embodiment in which the controller may be configured to position two motors and turn them on during a first time period T ₁ . In the exemplary embodiment of FIG. 4A, the controller 120 may orient the motor arm 90 with an angular displacement _Θ2 (position P2). The controller 120 may turn on the engine 36 for a turn-on duration Δt ₁ less than the first time period T ₁ . After the time Δt ₁ has elapsed, the controller 120 may orient the motor arm 92 with an angular displacement Θ ₃ (position P3). The controller 120 may turn on the motor 38 for a turn-on duration Δt ₂ that may be less than the first time period T ₁ . The controller 120 may select Δt ₁ and Δt ₂ such that the total time Δt ₁ +Δt ₂ may be less than the first time period T ₁ . Alternatively, the controller 120 may simultaneously orient both motor arms 90, 92 with angular displacements Θ ₂ (position P2) and Θ ₃ (position P3), respectively. After orienting the motor levers 90, 92, the controller 120 may turn on the motors 36 and 38 simultaneously or sequentially for on-times Δt ₁ and Δt ₂ , respectively, such that each on-time Δt ₁ and Δt ₂ may be less than the first period. T ₁ time. Duration Δt ₁ and Δt ₂ inclusion may be equal or unequal.

[081] According to embodiments of the present disclosure, said at least one controller may be configured to, during a second time period following the first time period, move the first motor to provide a second angular orientation and turn on the first motor. Said at least one controller may also be configured, during a second period of time, to move the second motor to provide the first angular orientation and turn on the second motor. In some embodiments of the present disclosure, the controller may be configured to change the positions of the first and second motors after a first period of time. Thus, for example, the controller may be configured to position the first motor to the second position, and the second motor to the first position, for a second period of time. The controller can position both motors to their respective positions simultaneously or sequentially. The controller may also turn on both motors simultaneously or in series. In some exemplary embodiments, the controller may position the first motor to a second position and turn on the first motor for a second on duration. After turning on the first motor during the second on duration, the controller may position the second motor to the first position and turn on the second motor during the first on duration. In other exemplary embodiments, the controller may position both the first and second motors to their respective second and first positions, respectively. After positioning both motors, the controller may turn on both the first and second motors for their respective second and first duty cycles.

[082] FIG. 4B shows an exemplary embodiment in which the controller may be configured to reposition the two motors and turn them on during a second time period T ₂ . In the exemplary embodiment of FIG. 4B, after the first time period T ₁ has elapsed, the controller 120 may orient the motor arm 90 with an angular displacement Θ ₃ (position P3). The controller 120 may turn on the motor 36 for a turn-on duration Δt ₃ less than the second time period T ₂ . After the turn-on duration Δt ₃ has elapsed, the controller 120 may orient the motor lever 92 with an angular displacement Θ ₂ (position P2). The controller 120 may turn on the motor 38 for a turn-on duration Δt ₄ that may be less than the second time period T ₂ . The controller 120 may select Δt ₃ and Δt ₄ such that the total on duration Δt ₃ +Δt ₄ can be less than the second time period T ₂ . Alternatively, the controller 120 may simultaneously orient both motor arms 90, 92 with angular displacements Θ ₃ (position P3) and Θ ₂ (position P2), respectively. After orienting the motor arms 90, 92, the controller 120 may turn on the motors 36 and 38 simultaneously or sequentially for turn-on times Δt ₃ and Δt ₄ , respectively, so that each of Δt ₃ and Δt ₄ may be less than the second period T ₂ times. Duration Δt ₃ and Δt ₄ inclusion may be equal or unequal. The turn-on times Δt ₃ and Δt ₄ can also be equal to or different from any of the turn-on times Δt ₁ and Δt ₂ .

[083] According to the present disclosure, the at least one controller may be further configured to move one of the first pair of motors and the second pair of motors in the first angular orientation. In some exemplary embodiments according to the present disclosure, a serving satellite may have more than one engine pair. In these exemplary embodiments, the controller may be configured to move one pair of motors such that both motors in the pair have the same orientation. The controller may orient the two motors in this first pair by adjusting the positions of the motor deployment mechanisms associated with said two motors.

[084] The at least one controller according to the present disclosure may also be configured to move the second motor of the first motor pair and the second motor pair to a second angular orientation different from the first angular orientation. In some illustrative embodiments, the controller may select a second pair of motors different from the first pair. The controller may be configured to move the second pair of motors such that both motors in the second pair have the same orientation. The controller may orient the two motors in the second motor pair by adjusting the positions of the motor deployment mechanisms associated with the two motors in the second motor pair.

[085] According to the present disclosure, the controller may be configured to select the first and second angular orientations so that the thrust vectors of the first pair of motors and the second pair of motors do not pass through the joint center of mass and are offset from the joint center of mass. This can be achieved, for example, when at least one controller adjusts the positions of one or more structural elements of the engine deployment mechanisms associated with the first and second pair of engines so that when the first and second pair of engines are turned on, the thrust vectors generated as the first pair of engines, and the second pair of engines, did not pass through the joint center of mass of the serving satellite and the main satellite. In some exemplary embodiments, the controller may choose to orient the first motor pair and the second motor pair such that the thrust vectors of the first and second motor pair are spatially separated (ie, offset) from the joint center of gravity of the serving satellite and the main satellite. In other illustrative embodiments, the controller may select the orientation of the first pair of engines and the second pair of engines such that the thrust vectors of the first and second pair of engines do not pass through any common center of mass of a plurality of joint centers of mass that may result from the connection of the serving satellite to many primary satellites, where each primary satellite has a different center of mass.

[086] FIG. 6A and 6B show illustrative embodiments in which the controller may be configured to orient the first and second pair of motors in different orientations. For example, as shown in FIG. 6A, the at least one controller 120 may orient the first motor pair 50 in the first orientation. The controller 120 may orient the motor arm 90 with an angular displacement Θ ₄ relative to the first fork 66 of the motors. The angular displacement Θ ₄ may determine the position P4 for the engine 36. The controller 120 may orient the engine arm 92 with the angular displacement Θ ₄ relative to the first fork 66 of the engines. Thus, for example, both motors 36 and 38 can be in position P4 when the arms 90, 92 of the motors are oriented with an angular displacement Θ ₄ . Controller 120 may turn on motors 36, 38. Turned on motors 36, 38 may generate thrust vectors 160, 162, respectively. As shown in FIG. 6A, the thrust vectors 160, 162 may not pass through the joint center of mass 126 of the coupled block 206. In some exemplary embodiments, as shown in FIG. 6A, the thrust vectors 160, 162 may intersect each other at an intersection point 164 that may be offset (ie, located at a distance) from a common center of mass 126. It is assumed that due to the fixed orientation of the thrust vector in FIG. 6A, serving satellite 10 may dock with a plurality of different primary satellites, each having a different center of mass, and intersection point 164 may be spatially separated from the joint centers of mass of all such tandem modules, regardless of the exact location of the joint center of mass in each case.

[087] As shown in FIG. 6B, the at least one controller 120 may orient the second motor pair 52 in the second orientation. For example, the controller 120 may orient the motor arm 94 with an angular displacement Θ ₅ relative to the second fork 68 of the motors. The angular displacement Θ ₅ may determine the position P5 for the engine 40. The controller 120 may also orient the engine lever 96 with the angular displacement Θ ₅ relative to the second fork 68 of the engines. Thus, for example, the motors 40 and 42 may be in position P5 when the arms 94, 96 of the motors are oriented with an angular displacement Θ ₅ . Controller 120 may turn on motors 40, 42. Turned on motors 36, 38 may generate thrust vectors 166, 168, respectively. As shown in FIG. 6B, thrust vectors 166, 168 may not pass through the joint center of mass 126 of coupled block 206. In some illustrative embodiments, as shown in FIG. 6B, thrust vectors 166, 168 may be generally parallel to each other and may be located at a distance from a common center of mass 126. Regardless of the particular center of mass of the main satellite, it is likewise assumed that there will be such a universal orientation of the engines that the thrust vectors 166, 168 will be located at a distance from any joint center of mass, regardless of the location of the joint center of mass of the tandem module.

[088] According to embodiments of the present disclosure, said at least one controller may be configured to turn on the motors located in a first angular orientation with a first level of thrust. Said at least one controller may also be configured to turn on the motors located in the second angular orientation, with a second thrust level different from the first thrust level, so that the torques generated by the thrust vectors about at least one axis of the connected block , were essentially balanced. In some illustrative embodiments according to the present disclosure, said at least one controller may select the thrust levels of the first pair of engines and the second pair of engines. The controller may select thrust levels such that the torque generated by the thrust vectors of the first pair of motors about the axis of the serving satellite is exactly equal and opposite to the torque generated by the thrust vectors of the second pair of motors of the two motors.

[089] FIG. 6A and 6B, for example, show configurations that controller 120 can use to balance torques. Thus, for example, in the illustrative embodiment of FIG. 6A, controller 120 can orient both motor arms 90, 92 with the same angular displacement Θ ₄ (position P4). Controller 120 may turn on motors 36 and 38 to generate thrust vectors 160, 162, respectively. The thrust vectors 160, 162 may generate torques about, for example, the x-axis, which may be located generally perpendicular to plane 62 (see FIG. 4B). The rotational force exerted on the coupled block 206 as a result of the generated torques may be represented by an arrow 170.

[090] Similarly, in the exemplary embodiment shown in FIG. 6B, controller 120 may orient both motor arms 94, 96 with the same angular displacement _Θ5 (position P5). Controller 120 may turn on motors 40 and 42 to generate thrust vectors 168, 170, respectively. The thrust vectors 168 and 170 can generate torques about, for example, the x-axis. The rotational force exerted on coupled block 206 as a result of the generated torques may be represented by arrow 172. Controller 120 may select the thrust levels of engines 36, 38, 40, and 42 such that the torque represented by arrow 170 is exactly equal to and is opposite to the torque represented by arrow 172, thereby balancing or nulling the resulting torque about the x-axis. It is contemplated that the thrust levels of engines 36, 38, 40, and 42 may be equal or unequal.

[091] In some illustrative embodiments according to the present disclosure, said at least one controller may be configured to simultaneously turn on the first pair of motors during the first period of time. Said at least one controller may also be configured to simultaneously turn on a second pair of motors during a second period of time. The term "simultaneously" as used herein indicates that the two engines included in the first or second pair of engines are turned on at approximately the same time and for approximately the same amount of time. The term "simultaneously" encompasses an embodiment in which there may be small time differences (on the order of, for example, 0.5 seconds) between the time at which firing is initiated or terminated in each of the two motors included in the first or second pair of motors. The term "simultaneous" also covers situations in which, during motor switching, each motor is pulsed and the firing of individual motors alternates, so that while multiple motors are switched on at the same time, they may not be combined on inclusion within this time interval. Said at least one controller may select the first and second times and thrust levels of the first and second pair of motors so that the torques generated by the first and second pair of motors relative to at least one axis of the serving satellite are set to zero. The first time period and the second time period may be equal or unequal.

[092] FIG. 6A and 6B, for example, show configurations in which controller 120 can simultaneously turn on the first and second pair of motors. For example, when motors 36 and 38 are oriented in the P4 orientation as shown in FIG. 6A, controller 120 may turn on motors 36 and 38 simultaneously for a first period of time T ₁ . Similarly, when motors 40 and 42 are oriented, for example, in orientation P5 as shown in FIG. 6B, controller 120 may turn on motors 40 and 42 simultaneously for a second period of time T ₂ . The time intervals T ₁ and T ₂ may be equal or unequal.

[093] According to embodiments of the present disclosure, the controller may be further configured to move the first pair of motors to a second angular orientation, and move the second pair of motors to the first angular orientation after a third period of time. The controller may also be configured to simultaneously turn on the second pair of motors during the first period of time after the movement of the first pair of motors and the second pair of motors. In some exemplary embodiments, the controller may begin timing the third time period after the first time period and the second time period have elapsed. In these embodiments, the third time period may be zero or non-zero. In other exemplary embodiments, the controller may begin counting a third period of time from the time the first pair of motors starts to operate. In these embodiments, the third time period may be approximately equal to or greater than at least the sum of the first and second time periods.

[094] As non-limiting examples, FIG. 7A and 7B show the positions of the first and second pair of motors after the third time period T ₃ has elapsed. In the exemplary embodiment of FIG. 7A, controller 120 can orient both motor arms 90 and 92 with the same angular displacement _Θ5 (position P5). Controller 120 may turn on motors 36 and 38 for a first time period T ₁ . As shown in the exemplary embodiment of FIG. 7B, the controller can orient both motor arms 94 and 96 with the same angular displacement Θ ₄ (position P4). Controller 120 may turn on motors 40 and 42 for a second time period T ₂ .

[095] According to some embodiments of the present disclosure, said at least one controller can be configured to turn on the engines located in the first angular orientation, with a given level of thrust during the first period of time. The controller may also be configured to turn on the engines located in the second angular orientation, with a given level of thrust during a second period of time different from the first period of time, so that the torques generated by the thrust vectors about at least one axis of the connected block , were essentially balanced. In some exemplary embodiments, the first and second time periods may be equal. In other exemplary embodiments, the first and second time periods may not be equal. It is also contemplated that, in some exemplary embodiment, the controller may turn on the first and second pair of motors simultaneously.

[096] As non-limiting examples, FIG. 6A and 6B show the configuration of the first and second pair of motors. As shown in the exemplary embodiment of FIG. 6A, controller 120 can orient both motor arms 90 and 92 with the same angular displacement Θ ₄ (position P4). Controller 120 may turn on engines 36 and 38 at a predetermined thrust level TH _PRE for a first time period T ₁ . As shown in the exemplary embodiment of FIG. 6B, controller 120 may orient both motor arms 94 and 96 with the same angular displacement _Θ5 (position P5). Controller 120 may turn on engines 40 and 42 at a predetermined thrust level TH _PRE for a second time period T ₂ .

[097] According to some embodiments of the present disclosure, the controller may be configured to determine a second time period. The controller may be configured to do this by turning on the motors located in the first angular orientation at a given level of thrust for a first period of time. The controller may also be configured to determine an angular momentum with respect to at least one coordinate axis of the connected satellite. Additionally, the controller may be configured to determine a second period of time during which the motors located in the second angular orientation must be turned on to reduce the angular momentum to essentially zero.

[098] As non-limiting examples, FIG. 6A and 6B, the controller 120 can orient both motor arms 90, 92 with the same angular displacement Θ ₄ (position P4). Controller 120 may turn on engines 36 and 38 at a predetermined thrust level TH _PRE for a first time period T ₁ . The controller 120 may determine the magnitude of the moment AM1 of the pulse generated relative to, for example, the x-axis of the connected block 206 (see Fig. 5C). The controller 120 may determine the second turn-on time interval T ₂ of the motors 40, 42 with a given thrust level TH _PRE so that the moment AM2 of the impulse generated by the thrust vectors 168, 170 about the x-axis is exactly equal to the moment AM1 of the impulse and has the opposite sign. In other words, the controller 120 may determine the time T ₂ such that the resulting pulse moment AM1+AM2 is essentially zero.

[099] In some illustrative embodiment of the present disclosure, the first period of time is the amount of time after which the reaction wheel of the serving satellite is fully loaded, and the second period of time is the amount of time after which the reaction wheel is fully unloaded. Some aspects of the present disclosure may include one or more reaction wheels located on board a serving satellite. As used here, the term "reaction wheel" refers to a device capable of storing angular momentum. In some exemplary embodiments, the reaction wheel may include a flywheel capable of rotating about an axis of rotation. The reaction wheel can maintain momentum by concomitantly increasing the flywheel speed. The reaction wheel may have a predetermined minimum speed and a predetermined maximum speed and may be considered fully loaded when it reaches its predetermined maximum speed.

[0100] As non-limiting examples, as shown in FIG. 6A, controller 120 can orient both motor arms 90 and 92 with the same angular displacement Θ ₄ (position P4). The controller 120 may turn on the motors 36 and 38 at a predetermined thrust level TH _PRE until the jet wheel in the service satellite 10 is fully loaded (ie reaches its predetermined maximum speed). The period of time required for the reaction wheel to be fully loaded may be the first period of time T ₁ . After the reaction wheel is fully loaded, controller 120 may stop turning on motors 36, 38 and start turning on motors 40, 42 instead (see FIG. 6B). Controller 120 may continue to turn on motors 40, 42 until the reaction wheel is fully unloaded (ie, reaches its predetermined minimum speed). The period of time required for complete unloading of the jet wheel may be a second period of time T ₂ .

[0101] According to some exemplary embodiments of the present disclosure, the controller may be configured to turn on a first pair of motors and a second pair of motors in series. As non-limiting examples, in FIG. 6A and 6B, after orienting motor arms 90, 92, 94, and 96, controller 120 may cause motors 36 and 38 to be turned on during a first period of time T ₁ . After the first period of time, the controller 120 may initiate the inclusion of the motors 40 and 42 during the second period T ₂ time. Thus, controller 120 may turn on the second pair of motors 40, 42 in series after turning on the first pair of motors 36, 38.

[0102] According to embodiments of the present disclosure, during the third period of time, after the second period of time, the controller may be configured to move the first pair of motors to a second angular orientation and move the second pair of motors to the first angular orientation. The controller may also be configured to sequentially turn on the first pair of motors and the second pair of motors after moving the first pair of motors and the second pair of motors. After turning on motors 36 and 38 for a first period of time T ₁ , and after turning on motors 40 and 42 for a second period of time T ₂ , controller 120 may be configured to change the positions of motors 36, 38, 40, and 42 during a third interval T ₃ time. Thus, for example, the controller 120 may change the orientation of the motor arms 90 and 92 from an angular displacement of Θ ₄ (position P4) (as in FIG. 6A) such that the motor arms 90 and 92 are oriented with an angular displacement of Θ ₅ (position P5 ) (as in Fig. 7A). Similarly, the controller 120 may change the orientation of the motor arms 94 and 96 from the same angular displacement Θ ₅ (position P5) (as in Fig. 6A) to an angular displacement Θ ₄ (position P4) (as in Fig. 7A) in during the interval T ₃ time. The controller 120 may change the orientations of the motor arms 90, 92, 94, and 96 simultaneously or sequentially in any order. After reorienting the motor arms 90, 92, 94, and 96, the controller 120 may turn on either the motors 36, 38 or the motors 40, 42 at a given thrust level TH _PRE for the first time T ₁ . After a period of time T ₁ has elapsed, controller 120 may turn on another pair of motors 36, 38 or motors 40, 42 at a given thrust level TH _PRE for a second period of time T ₂ .

[0103] The present disclosure may also relate to a method for providing position keeping services to a primary satellite. As discussed above, position maintenance may include maneuvers associated with providing compensatory offsets required to maintain the primary satellite in its assigned position in the geostationary orbit. In some illustrative embodiments, the method may include the step of launching a serving satellite into space, and the step of maneuvering it to within the docking distance of the main satellite. The term "launch" refers, in general, to placing a serving satellite into some orbit in space. According to some aspects of the present disclosure, a serving satellite may be launched into space on an aircraft carrier or booster that flies from Earth into space. A carrier aircraft or booster may separate a serving satellite at a given orbit in space. According to other aspects of the present disclosure, a serving satellite may be launched into space on a reusable carrier aircraft, such as a space shuttle. The satellite can separate from the space shuttle in a given orbit. The serving satellite may be a microsatellite that may be launched into space in a common carrier aircraft with other satellites or other payloads.

[0104] According to some exemplary embodiments of the present disclosure, a method of providing position-keeping services to a primary satellite may include the step of connecting a serving satellite to a primary satellite to form a connected unit by engaging at least two arms of the serving satellite with an external docking ring of the primary satellite . The connected block may have a common center of mass. In some illustrative embodiments, the method may also include the step of selectively moving each of the at least two engines of the serving satellite to be activated during position maintenance maneuvers such that the thrust vectors of the at least two engines do not pass through a common center. masses and were displaced from the joint center of mass.

[0105] FIG. 8 shows an exemplary method 800 for providing position keeping services to a primary satellite 200. The order and arrangement of the steps in method 800 is provided for purposes of illustration. As will be appreciated from this disclosure, modifications to method 800 may be implemented by, for example, adding, merging, deleting, and/or rearranging the steps of method 800. Certain steps of method 800 are described as being performed by controller 120 of serving satellite 10. It is contemplated, however, that these steps may additionally or alternatively be performed by a controller located at a ground control station or on another spacecraft. It is also contemplated that, in some exemplary embodiments, controller 120 of serving satellite 10 may perform the disclosed steps based on commands received by controller 120 from a controller located at a ground control station or other spacecraft.

[0106] Method 800 may include the step of launching serving satellite 10 (step 802). Launching the serving satellite 10 may include loading the serving satellite 10 into the payload bay of the carrier aircraft. The carrier aircraft may include a rocket, rocket, reusable spacecraft, space shuttle, or any other carrier capable of transporting a serving satellite from Earth into orbit. Thus, the step of launching the serving satellite 10 may further include the step of enabling the carrier spacecraft to fly from the surface of the Earth into space. The step of launching the serving satellite 10 may also include the step of separating the serving satellite 10 into a predetermined orbit in space. In some exemplary embodiments, serving satellite 10 may be separated in an orbit other than geostationary orbit.

[0107] Method 800 may include the step of maneuvering the serving satellite 10 to within the docking distance of the main satellite 200 (step 804). The stage of maneuvering the serving satellite 10 may include, for example, the stage of orienting at least two of the levers 90, 92, 94, 96 of the engines with an angular displacement Θ ₁ (position P1) relative to the plane of the corresponding fork 66, 68 of the engines deployment. Fig. 1B shows the position P1 of the engines 36 and 40. The step of maneuvering the serving satellite 10 may include, for example, turning on two or more engines 36, 38, 40, 42 oriented to the position P1 to move the serving satellite to within a predetermined geostationary distance. orbit. In some illustrative embodiments, the orbit of the serving satellite 10 may be at an altitude of approximately 42166 km.

[0108] Method 800 may include the step of connecting serving satellite 10 to main satellite 200 (step 806). There are many ways to form such a connection, and this way in its broadest sense is not limited to any particular design. As an example, the step of attaching serving satellite 10 may include the step of deploying one or more docking arms 16 of serving satellite 10. Controller 120 of serving satellite 10 may adjust the docking arms 16 such that the ring-engaging portions 34 of one or more docking arms can be positioned to receive the docking ring 202 of the main satellite 200. The controller 120 can adjust the positions of the docking arms 16 so that the ring engaging portions 34 can engage the docking ring 202 to engage the docking ring 202 at one or more locations. The docking ring 202 engagement step may allow the serving satellite 10 to dock with the main satellite 200 to form a connected unit 206.

[0109] Method 800 may include the act of selectively moving at least two engines of the serving satellite (act 808). There are many ways to move motors, and this method, in its broadest sense, is not limited to any particular controller design or logic. As an example, the controller 120 of the serving satellite 10 may move two or more motor arms 90, 92, 94, 96 with one of the angular displacements Θ ₂ (position P2), Θ ₃ (position P3), Θ ₄ (position P4), or Θ ₅ (position P5). Controller 120 may select positions P2, P3, P4, or P5 such that when one or more motors 36, 36, 40, 42 are turned on, one or more vectors 122, 124, 132, 134, 160, 162, 166, or 168 thrust did not pass through the joint center 126 mass.

[0110] Method 800 may include turning on one or more motors 36, 38, 40, 42 (step 810). For example, controller 120 may turn on one or more motors 36, 38, 40, 42 for one or more periods T ₁ , T ₂ , T ₃ , and so on. time to help ensure that the main satellite 200 can remain in its assigned geostationary area. Of course, there are many ways, schemes and methods for synchronizing motors, and this method in its broadest sense is not limited to any particular of them.

[0111] According to some exemplary embodiments of the present disclosure, the step of selectively moving motors in a method for providing position keeping services to a primary satellite may include the following steps. The method may include the step of positioning the first engine of the at least two engines in the first angular orientation and the step of turning on the first engine during the first period of time. The method may also include the step of positioning the second motor of the at least two motors in a second angular orientation different from the first angular orientation, and turning on the second motor during the first period of time. Additionally, the method may include the step of moving the first motor to provide the second angular orientation and the step of turning on the first motor during a second period of time following the first period of time. Additionally, the method may include the step of moving the second motor to provide the first angular orientation and the step of turning on the second motor for a second period of time.

[0112] FIG. 9 shows an exemplary method 900 for providing position keeping services to the main satellite 200 by moving the thrusters as described in the example above. The order and arrangement of the steps in the method 900 is provided for purposes of illustration. As will be appreciated from this disclosure, modifications to method 900 may be implemented by, for example, adding, merging, deleting, and/or rearranging the steps of method 900. Certain steps of method 900 are described in the following disclosure as being performed by controller 120 of serving satellite 10. It is assumed however, that these steps may additionally or alternatively be performed by a controller located at a ground control station or on another spacecraft. It is also contemplated that, in some exemplary embodiments, controller 120 of serving satellite 10 may perform the disclosed steps based on commands received by controller 120 from a controller located at a ground control station or other spacecraft.

[0113] Method 900 includes orienting the first engine to position P2 and the second engine to position P3 (block 902). In one illustrative embodiment, the controller 120 may orient the motor arm 90 with an angular offset _Θ2 relative to the motors deployment fork 66 so that the motor 36 is in position P2 (see FIG. 4A). The controller 120 may also orient the motor arm 92 with an angular displacement Θ ₃ relative to the motor yoke 66 so that the motor 38 is in position P3 (see FIG. 4A). It should be understood that the method described with reference to FIG. 9 is not limited to a particular choice of engines and orientations. For example, in some embodiments, the controller 120 may instead orient the motor arm 90 with an angular displacement Θ ₃ and orient the motor arm 92 with an angular displacement Θ ₂ (see FIG. 4B).

[0114] Method 900 may include turning on the first and second engines at a first thrust level for a first on duration (act 902). For example, when engine 36 is in position P2 and engine 38 is in position P3 (see FIG. 4A), controller 120 may turn on engines 36 and 38 at thrust level TH1 for the first on duration Δt ₁ .

[0115] Method 900 may include the step of determining torques and/or angular momentum about one or more coordinate axes (step 904). In one exemplary embodiment, controller 120 may determine one or more torques and/or angular momentum about one or more of the x, y, or z coordinate axes of coupled block 206. Controller 120 may determine torque and/or angular momentum based on measurements of force, rotational speeds, which can be obtained from one or more sensors located on the serving satellite 10 or the main satellite 200. In one illustrative embodiment, the controller 120 can determine the torque F1 or moment AM1 of the impulse about the x-axis (see for example , Fig. 5C) of the serving satellite 10.

[0116] In one illustrative embodiment, the controller 120 may perform steps 902-906 during the first period T ₁ of time. In other exemplary embodiments, during the first time period T ₁ , controller 120 may turn on motors 36 and 38 simultaneously. It is also contemplated that, in some embodiments, during the first time period T ₁ , controller 120 may turn on motors 36 and 38 in series in any order.

[0117] Method 900 may include orienting the first engine to position P3 and the second engine to position P2 (block 908). At method step 908, controller 120 may change the positions of the engines selected at step ₉₀₂ , for example. engine 36 was in position P3 (see FIG. 4B). Similarly, controller 120 may orient engine lever 92 previously in position P3 with an angular offset _Θ2 relative to engine yoke 66 so that engine 38 is in position P2 (see FIG. 4B).

[0118] Method 900 may include turning on the first and second engines at a second thrust level for a second on duration (act 910). For example, when engine 36 is in position P3 and engine 38 is in position P2, controller 120 may turn on engines 36 and 38 at thrust level TH2 for a second on-duration Δt ₂ .

[0119] Method 900 may include the step of determining torques and/or angular momentum about one or more coordinate axes (step 912). Controller 120 may perform one or more steps similar to those described above with respect to, for example, step 906. In one illustrative embodiment, controller 120 may determine torque F2 or moment AM2 about the x-axis (see, for example, FIG. 5B) serving satellite 10.

[0120] In one exemplary embodiment, controller 120 may perform steps 908-912 during a second time period T ₂ . In other exemplary embodiments, during the second time period T ₂ , controller 120 may turn on motors 36 and 38 simultaneously. It is also contemplated that, in some embodiments, during the second time period T ₂ , controller 120 may turn on motors 36 and 38 sequentially in any order. The time intervals T ₁ and T ₂ may be equal or unequal.

[0121] Method 900 may include the step of determining first and/or second thrust levels to zero out the resulting torque and/or momentum (step 914). In one exemplary embodiment, controller 120 may determine one or both thrust levels TH1 and TH2 such that the resulting torque F1+F2 and/or the resulting momentum AM1+AM2 about, for example, the x-axis is substantially zero.

[0122] Method 900 may include the act of turning on the engines at the first thrust level while orienting to position P2 (act 916). In one exemplary embodiment, controller 120 may turn on any of the motors 36, 38 at thrust level TH1 when motors 36 and 38 are oriented to position P2. The method 900 may also include the act of turning on the engines with the second level of thrust while orienting to position P3 (act 918). In one exemplary embodiment, controller 120 may turn on any of the motors 36, 38 at thrust level TH2 when motors 36 and 38 are oriented to position P3.

[0123] While the above disclosure describes method steps 902-918 with respect to motors 36, 38, the present disclosure in its broadest sense is not limited to this configuration and to no particular motor design or sequence or angular orientation. For example, in some embodiments according to the present disclosure, the controller may select motor arms 94, 96 instead of motor arms 90, 92 to orient motor arms with one of angular displacements Θ ₂ or Θ ₃ . Controller 120 may perform steps 902-918 of method 900 using motors 40, 42. When controller 120 first performs steps 902-918 using motors 40, 42, controller 120 may repeat steps 902-918 using a different pair of motors 36, 38 after approximately 12 hours. Controller 120 may also repeat steps 902-918 using both motor pair 36, 38 and motor pair 40, 42 after a predetermined period of time to help ensure that the primary satellite remains in its assigned geostationary area.

[0124] It is also contemplated that, in some illustrative embodiments, controller 120 may first perform steps 902-918 using motors 36, 40. Thus, for example, at step 902, controller 120 may orient motor arm 90 with an angular displacement _Θ fork 66 to deploy the engines so that the engine 36 is in position P2. The controller 120 may also orient the motor arm 94 with an angular displacement Θ ₃ relative to the motor yoke 68 so that the motor 42 is in position P3. Similarly, at step 908, the controller 120 may orient the motor arm 90 with an angular displacement Θ ₃ relative to the motor deployment fork 66 so that the motor 36 is in position P3. The controller 120 may also orient the motor arm 94 with an angular displacement _Θ2 relative to the motor yoke 68 so that the motor 42 is in position P2. After performing steps 902-918 using motors 36, 40, the controller may repeat steps 902-918 using motor arms 92, 96 and corresponding motors 38, 42 after approximately 12 hours have elapsed. Controller 120 may also repeat steps 902-918 with both motor pair 36, 40 and motor pair 38, 42 after a predetermined period of time to help ensure that the primary satellite remains in its assigned geostationary area.

[0125] FIG. 10 shows another exemplary method 1000 for providing position keeping services to a primary satellite 200. The order and arrangement of the steps in method 1000 is provided for purposes of illustration. As will be appreciated from this disclosure, modifications may be made to method 900 by, for example, adding, merging, deleting, and/or rearranging steps of method 1000. Certain steps of method 1000 are described in the following disclosure as being performed by controller 120 of serving satellite 10. It is assumed however, that these steps may additionally or alternatively be performed by a controller located at a ground control station or other spacecraft. It is also contemplated that, in some illustrative embodiments, controller 120 of serving satellite 10 may perform the disclosed steps based on commands received by controller 120 from a controller located at a ground control station or other spacecraft.

[0126] Method 1000 includes orienting the first pair of motors to position P4 and the second pair of motors to position P5 (1002). In one exemplary embodiment, controller 120 may orient motor arms 90, 92 with an angular offset of _Θ4 relative to motor yoke 66 so that motors 36 and 38 can be in position P4 (see FIG. 6A). The controller 120 may also orient the motor arms 94, 96 with an angular displacement _Θ5 relative to the motor yoke 68 so that the motors 40 and 42 can be in position P5 (see FIG. 6A). It should be understood that the method described in connection with FIG. 10 is not limited to any particular choice of engines and orientations. For example, in some embodiments, controller 120 may instead orient Θ ₅ motor arms 90 and 92 and orient Θ ₄ motor arms 94 and 96 .

[0127] Method 1000 may include turning on the first pair of engines at a given thrust level (block 1004). For example, when motors 36 and 38 are in position P4, controller 120 may turn on motors 36 and 38 at a given thrust level TH _PRE (see FIG. 6A). Method 1000 may include the step of determining if the reaction wheels are fully loaded (step 1006). In some exemplary embodiments, controller 120 may determine if the reaction wheels associated with serving satellite 10 are fully loaded (ie, have reached their predetermined maximum rotational speeds). When controller 120 determines that the reaction wheels associated with serving satellite 10 are not fully loaded (block 1006: No), method 1000 may return to block 1004 to continue firing engines 36 and 38 at the desired thrust level TH _PRE . However, when controller 120 determines that the reaction wheels associated with serving satellite 10 are fully loaded (block 1006: Yes), method 1000 may proceed to block 1008.

[0128] Step 1008 of method 1000 may include the step of determining the turn-on duration Δt ₁ to fully load the reaction wheels. In some exemplary embodiments, controller 120 may stop turning on engines 36 and 38 and determine the duration Δt ₁ required to fully load the reaction wheels associated with serving satellite 10 as a result of turning on engines 36 and 38 at a given thrust level TH _PRE .

[0129] Method 1000 may include turning on the second pair of engines at a given thrust level (act 1010). For example, when motors 40 and 42 are in position P5, controller 120 may turn on motors 40 and 42 at a predetermined thrust level TH _PRE (see FIG. 6B). Method 1000 may include the step of determining if the jet wheels are fully unloaded (step 1012). In some exemplary embodiments, controller 120 may determine if the reaction wheels associated with serving satellite 10 are fully unloaded (ie, if they have reached their predetermined minimum rotational speeds). When controller 120 determines that the reaction wheels associated with serving satellite 10 are not fully unloaded (block 1012: No), method 1000 may return to block 1010 to continue firing engines 40 and 42 at the desired thrust level TH _PRE . However, when controller 120 determines that the reaction wheels associated with serving satellite 10 are fully unloaded (block 1012: Yes), method 1000 may proceed to block 1014.

[0130] Step 1014 of method 1000 may include the step of determining a turn-on duration Δt ₂ for complete unloading of the reaction wheels. In some exemplary embodiments, controller 120 may stop turning on engines 40 and 42 and determine the duration Δt ₂ required to completely unload the reaction wheels associated with serving satellite 10 by turning on engines 40 and 42 at a given thrust level TH _PRE .

[0131] Method 1000 may include turning on the engines at a given thrust level TH _PRE for a first time period Δt ₁ while orienting to position P4 (step 1016). In one exemplary embodiment, controller 120 may turn on any of the motors 36, 38, 40, 42 at a given thrust level TH _PRE during the first time period Δt ₁ when any of the motors 36, 38, 40, 42 are oriented to position P4.

[0132] Method 1000 may also include turning on the engines at a given thrust level TH _PRE for a second time period Δt ₂ while orienting to position P5 (step 1018). In one exemplary embodiment, controller 120 may turn on any of the motors 36, 38, 40, 42 at a given thrust level TH _PRE for a second time period Δt ₂ when any of the motors 36, 38, 40, 42 are oriented to position P5.

[0133] Thus, for example, in some embodiments, controller 120 may orient the first pair of motors 36 and 38 to position P4 and turn on motors 36 and 38 at a given thrust level TH _PRE for a first period of time Δt ₁ . The controller 120 may also orient the second pair of motors 40 and 42 to position P5 and turn on the motors 40 and 42 at a predetermined thrust level TH _PRE for a second time period Δt ₂ . After approximately 12 hours have elapsed, controller 120 may orient the first pair of motors 36 and 38 to position P5 and turn on motors 36 and 38 at a predetermined thrust level TH _PRE for a second period of time Δt ₂ . Additionally, controller 120 may orient the second pair of motors 40 and 42 to position P4 and turn on motors 40 and 42 at a predetermined thrust level TH _PRE for a first time period Δt ₁ . Controller 120 may repeat these steps after a predetermined period of time to help ensure that the primary satellite remains in its assigned geostationary area.

[0134] While the above disclosure describes steps 1002-1018 with respect to the first pair of motors 36, 38 and the second pair of motors 40, 42, neither method 1000 nor the present disclosure in its broadest sense is limited to this configuration. For example, in some embodiments according to the present disclosure, the controller may select motors 36 and 40 as the first motor pair, and motors 38 and 40 as the second motor pair, to perform method steps 1002-1018.

[0135] Some of the disclosed embodiments, depending on the implementation, may provide some advantages over conventional position maintenance techniques. For example, in embodiments of the present disclosure, it is not necessary to determine the exact location of the joint center of mass of the connected unit, including the serving satellite and the main satellite. Instead, the positions P2, P3, P4, and P5 of the engines corresponding to the angular displacements Θ ₂ , Θ ₃ , Θ ₄ , Θ ₅ , respectively, can be set and can be the same regardless of the size and/or mass of the main satellite . Specifically, the engine positions P2, P3, P4, and P5 may be chosen such that the thrust vectors of any engines of the main satellite do not pass through any of the joint centers of mass of the connected units, including the serving satellite and the plurality of main satellites with which the serving satellite can dock in space. Instead, the thrust vectors of the engines oriented to any of the engine positions P2, P3, P4, and P5 of the engines may be offset (ie, may be at a distance) from all common centers of mass of the plurality of connected blocks.

[0136] The disclosed embodiments may also be based on the recognition that it may be difficult to accurately determine the joint center of mass of the connected block. For example, as the fuel in the serving satellite or primary satellite is consumed, the joint center of mass may change. Additionally, errors in determining the exact mass distribution of the serving satellite and the main satellite may lead to errors in determining the joint center of mass. The disclosed serving satellite may advantageously provide position keeping services without relying on the joint center of mass of the serving satellite and the main satellite.

[0137] The disclosed serving satellite may provide position keeping services via a variable thrust method (eg, FIG. 9 method 900) or a variable time method (eg, FIG. 10 method 1000). As detailed in the above disclosure, in the variable thrust method, a serving satellite may position a pair of thrusters on the same side (north, south, west, or east) at positions P2 and P3, respectively. Selected engines can be turned on with the first thrust level TH1. Torques and/or moments of impulse generated as a result of these inclusions of motors with respect to at least one axis of the connected block can be determined. The serving satellite may then reposition the thrusters so that the thruster previously positioned at position P2 moves to position P3, and vice versa. The reoriented motors may be turned on with a second thrust level TH2, which may be selected such that the torques and/or angular momentums generated about said at least one axis may be substantially compensated or nulled out.

[0138] The serving satellite may then position the pair of thrusters on the same side (north, south, west, or east) at positions P2 and P3, respectively. The serving satellite may turn on selected thrust level TH1 thrusters, reposition the thrusters to turn on thrust level TH2 thrusters, and repeat the process to provide the desired translational motion for the coupled unit while ensuring that any residual torques are zeroed out. The serving satellite may repeat this procedure with the engines on the opposite side every 12 hours. Thus, the serving satellite can preferably provide positioning services to the main satellite without determining the joint center of mass of the serving satellite and the main satellite, and without turning on the thrusters towards the joint center of mass.

[0139] As detailed in the above disclosure, in the variable time method, the serving satellite may position both engines of the first engine pair on the same side (north, south, west, or east), for example, to position P4. The serving satellite may position a second engine pair different from the first engine pair, for example, to position P5. The second pair of motors may be located on the opposite side of the first pair of motors. Both engines of the first engine pair may be turned on at a predetermined thrust level TH _PRE for a first time period T ₁ until one or more reaction wheels of the serving satellite or the main satellite are fully loaded. After the first period T ₁ time, the inclusion of the first pair of engines may be terminated. The serving satellite may then turn on the second pair of thrusters at a given thrust level TH _PRE . The serving satellite may determine a second period of time T ₂ required to unload one or more reaction wheels. It should be noted that neither the thrust vectors of the first pair of engines nor the thrust vectors of the second pair of engines pass through the joint center of mass of the serving satellite and the main satellite.

[0140] The serving satellite may turn on the first pair of engines with thrust level TH _PRE during the first time period T ₁ and the second pair of engines with thrust level TH _PRE during the second time period T ₂ . After approximately 12 hours, the serving satellite may change the positions of the first and second pairs of engines. Namely, the first pair of motors previously oriented to position P4 can be reoriented so that the first pair of motors is in position P5. Similarly, the second pair of motors previously oriented to position P5 may be reoriented so that the second pair of motors is in position P4. The serving satellite may then turn on the first pair of engines at thrust level TH _PRE for a second time period T ₂ and the first pair of engines at thrust level TH _PRE for a first time period T ₁ . The serving satellite may repeat this procedure after a predetermined period of time has elapsed. Thus, the serving satellite can provide positioning services to the main satellite without determining the joint center of mass of the serving satellite and the main satellite, and without turning on the thrusters towards the joint center of mass.

[0141] Various changes and modifications may be made to the disclosed illustrative embodiments without departing from the spirit and scope of the present disclosure as set forth in the following claims. The description of the invention and the examples are intended to be regarded as illustrative only, with the true scope and spirit of the present invention being indicated by the following claims.

Claims (49)

1. Maintaining the position of the serving satellite, containing: body; a gripping mechanism attached to the body and configured to be attached to the main satellite to form a connected unit containing the main satellite and the serving satellite and having a common center of mass; a first deployable extension comprising a first fork arm rotatably connected to the first motor arm, wherein the proximal end of the first fork arm is rotatably connected to said body, and the distal end of the first motor arm is fixedly attached to the first motor, the first motor being configured to creating a thrust vector of the first engine directed along the thrust axis of the first engine and directed towards the body of the main satellite; a second deployable extension comprising a second fork arm rotatably connected to the second motor arm, wherein the proximal end of the second fork arm is rotatably connected to said body, and the distal end of the second motor arm is fixedly attached to the second motor, the second motor being configured to creating a thrust vector of the second engine directed along the thrust axis of the second engine and directed towards the body of the main satellite; a sensor for detecting an angular momentum or rotational speed of said connected unit; a controller configured to turn on the first engine and the second engine so that the thrust axis of the first engine intersects the thrust axis of the second engine at the point of intersection of the thrust vectors located inside the body of the main satellite; and the coupled unit is maintained in a substantially stationary orbit by turning on the first engine and the second engine. 2. The serving satellite of claim 1, wherein turning on the first engine and turning on the second engine substantially reduces the angular momentum or rotational speed of the coupled unit to about zero. 3. The serving satellite of claim 1, wherein, at the time the engine is turned on, the thrust vectors of each of the first engine and the second engine do not pass through the joint center of mass and intersect with the longitudinal plane of the connected unit on opposite sides of the joint center of mass. 4. The serving satellite of claim 1, wherein the first engine and the second engine are positioned such that the joint center of mass lies between the intersection points of the longitudinal plane of the connected unit and the thrust vectors of each of the first engine and the second engine. 5. The serving satellite of claim 1, wherein the controller is configured to turn on the first motor in a predefined first orientation from a set of predefined first orientations and to turn on a second motor in a predefined second orientation from a set of predefined second orientations. 6. The serving satellite of claim 1, wherein the first engine is positioned on a first side of the serving satellite and the second engine is positioned on a second side of the serving satellite opposite the first side. 7. Serving satellite according to claim 1, further comprising: a third motor arm connected to the first fork arm, the distal end of the third motor arm being attached to the third motor, and a fourth motor arm connected to the second fork arm, the distal end of the fourth motor arm being attached to the fourth motor. 8. Serving satellite according to claim 7, in which the first engine and the third engine are at a distance from each other and positioned in different predetermined orientations; And the second motor and the fourth motor are spaced apart and positioned in different predetermined orientations. 9. Serving satellite according to claim 7, in which the first engine and the third engine are placed on the first side of the serving satellite; And the second engine and the fourth engine are located on the second side of the serving satellite, which is opposite to the first side. 10. Maintaining the position of the serving satellite containing: body; a gripping mechanism attached to the body and configured to be attached to the outer surface of the main satellite to form a connected unit containing the main satellite and the serving satellite and having a common center of mass; a first deployable extension comprising a first fork arm and a first engine arm, the first fork arm being rotatably attached to the serving satellite at a first end and rotatably connected at a second end to a first end of the first engine arm, the second end of the first engine arm being attached to a first engine, the first engine being configured to create a first engine thrust vector directed along the first engine thrust axis and directed toward the main satellite body; a second deployable extension comprising a second yoke arm and a second motor arm, the second yoke arm being rotatably attached to the serving satellite at a first end and rotatably connected at a second end to a first end of a second motor arm, the second end of the second motor arm being attached to the second engine, and the second engine is configured to create a second engine thrust vector directed along the thrust axis of the second engine and directed towards the body of the main satellite; a controller configured to turn on the first engine and to turn on the second engine so that the thrust axis of the first engine intersects the thrust axis of the second engine at the point of intersection of the thrust vectors located inside the body of the main satellite; and: the first engine is located on the first side of the serving satellite; And the second engine is located on the second side of the serving satellite opposite the first side; And the coupled unit is maintained in a substantially stationary orbit by the operation of the first engine and the second engine. 11. The serving satellite of claim 10, wherein, at the time the engine is turned on, the thrust vectors of each of the first engine and the second engine do not pass through a common center of mass. 12. The serving satellite of claim 10, wherein the second end of the first engine arm is fixedly attached to the first engine, and the second end of the second engine arm is fixedly attached to the second engine. 13. The serving satellite of claim 10, wherein the activation of the first engine and the activation of the second engine occur simultaneously. 14. The serving satellite of claim 10, wherein the controller turns on the first engine in a predetermined first orientation from the set of predefined first orientations and turns on the second engine in a predetermined second orientation from the set of predefined second orientations. 15. Maintaining the position of the serving satellite containing: body; a gripping mechanism attached to the body and configured to be attached to the outer surface of the main satellite to form a connected unit containing the main satellite and the serving satellite and having a common center of mass; a first deployable extension rotatably attached to the serving satellite at a first end and coupled at a second end to a first engine, the first engine being configured to generate a thrust vector of the first engine directed along the thrust axis of the first engine and directed toward the body of the main satellite; a second deployable extension rotatably attached to the serving satellite at a first end and coupled at a second end to a second engine, the second engine being configured to generate a second engine thrust vector directed along the thrust axis of the second engine and directed toward the body of the main satellite; a controller turning on the first engine and turning on the second engine so that the thrust axis of the first engine intersects the thrust axis of the second engine at a point of intersection of the thrust vectors inside the body of the main satellite; and: the first engine is located on the first side of the serving satellite; And the second engine is located on the second side of the serving satellite opposite the first side; And the coupled unit is maintained in a substantially stationary orbit by the operation of the first engine and the second engine. 16. The serving satellite of claim 15, wherein the controller turns on the first engine in a predetermined first orientation from the set of predefined first orientations and turns on the second engine in a predetermined second orientation from the set of predetermined second orientations. 17. The serving satellite of claim 16, wherein, at the time the engine is turned on, the thrust vectors of each of the first engine and the second engine do not pass through a common center of mass. 18. Serving satellite according to claim 15, further comprising: a third engine connected to the first deployable extension; And a fourth engine connected to a second deployable extension. 19. The serving satellite of claim 15, wherein the gripping mechanism is operable to be attached to a docking ring formed from the outer surface of the main satellite.

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