Docking Structure

Abstract

A docking structure (1) for a satellite includes a magnetic plate (2) and a housing (4) for mounting and restraining the magnetic plate. The magnetic plate includes an outer surface and an inner surface. The magnetic plate includes a soft magnetic material. The housing extends around at least a portion of the periphery of the magnetic plate and over at least a portion of the outer surface and over at least a portion of the inner surface of the magnetic plate to mount and restrain the magnetic plate.

Description

[Technical field]

[0001] The present invention relates to a docking structure for a satellite, and in particular to a docking structure for mounting to a satellite, enabling the satellite to be captured in space by another spacecraft. [Background technology]

[0002] Thousands of artificial satellites and other objects orbit above the Earth. When these objects no longer serve a useful function, e.g., at the end of their operational life, they become "space junk" and can cause problems for other (e.g., operational) satellites. When unwanted satellites and objects leave their operational orbits, the potential for these structures to cause damage to other satellites and objects increases. This situation is becoming more acute as the number of satellites and objects orbiting above the Earth increases.

[0003] U.S. Patent Publication No. 2019 / 0241286 discloses a robotic capture interface that is attached to a satellite or object to be retrieved. The interface is captured by a complementary device on another spacecraft, allowing the satellite or object to be manipulated, such as removed from orbit, relocated to another orbit, or serviced. The capture interface includes a magnetized plate that is held in place using a hybrid system of adhesives and fasteners. Summary of the Invention [Problem to be solved by the invention]

[0004] SUMMARY OF THE PRESENT EMBODIMENT It is an object of the present invention to provide an improved docking structure for a satellite. [Means for solving the problem]

[0005] Viewed from a first aspect, the present invention provides a docking structure for a satellite, the docking structure comprising: A magnetic plate; a housing for mounting and restraining the magnetic plate; the magnetic plate having an outer surface and an inner surface; the magnetic plate includes a soft magnetic material; The housing extends around at least a portion of the periphery of the magnetic plate, extends over at least a portion of the outer surface of the magnetic plate, and extends over at least a portion of the inner surface of the magnetic plate for mounting and restraining the magnetic plate.

[0006] The present invention provides a docking structure for (e.g., for attachment to) a satellite, i.e., a docking structure that allows the satellite to be captured (via the docking structure) by another spacecraft. The docking structure includes a magnetic plate having an outer surface and an inner surface, and a periphery (e.g., extending between the outer surface and the inner surface). The magnetic plate is made from a soft magnetic (i.e., non-permanent) material.

[0007] The housing of the docking structure is used to mount and restrain the magnetic plate within the docking structure, the housing extending around (e.g., surrounding) at least a portion of the exterior surface, at least a portion of the perimeter, and at least a portion of the interior surface of the magnetic plate.

[0008] It will be appreciated that by providing a housing to which the magnetic plate is attached and constrained in a mechanical manner, the geometry of the housing extending around the interior and exterior surfaces and at least a portion of the periphery allows for the selection of optimal materials for the housing and magnetic plate. For example, the housing may be made from a lightweight and rigid material to provide strength to the structure, and the magnetic plate may be made from a suitable material that is magnetically soft.

[0009] This serves the primary mechanical robustness and durability of the docking structure, since the structural function of the housing is decoupled from the magnetic attraction function of the magnetic plate. The attachment and constraint of the magnetic plate by the geometry of the housing also allows for the avoidance of the use of any adhesives to hold the magnetic plate on the docking structure. Furthermore, the arrangement of the magnetic plate and housing serves to reduce the effects of thermal cycling, which can be extreme in space, on different components of the docking structure, as compared to a magnetic plate attached to the rest of the docking structure via, for example, adhesives.

[0010] The magnetic plate of the docking structure has an outer surface and an inner surface, and a perimeter. Preferably, the outer surface is arranged to face away from the satellite to which the docking structure is attached. Preferably, the inner surface is arranged to face towards the satellite to which the docking structure is attached. Preferably, the perimeter forms a boundary between the outer surface and the inner surface, e.g., extends between the outer surface and the inner surface.

[0011] The magnetic plate can have any suitable and desired geometric shape. Preferably, the outer surface has a maximum dimension (e.g., width or diameter) that is greater (e.g., significantly greater) than the thickness (e.g., in a direction perpendicular to the outer and / or inner surfaces) of the magnetic plate. Preferably, the inner surface has a maximum dimension (e.g., width or diameter) that is (e.g., significantly) greater than a thickness (e.g., perpendicular to the outer surface and / or inner surface) of the magnetic plate. Preferably, the outer surface has a maximum dimension (e.g., width or diameter) that is substantially the same as the maximum dimension (e.g., width or diameter) of the inner surface.

[0012] The magnetic plate may have any suitable and desired dimensions as required, for example to suit the size and mass of the satellite to be attached. In one embodiment, the magnetic plate has a thickness (dimension between the outer and inner surfaces) of between 0.1 mm and 5 mm, e.g., 0.2 mm and 2 mm, e.g., 0.3 mm and 1 mm, e.g., about 0.5 mm. In one embodiment, the magnetic plate has a maximum dimension (e.g., diameter) of between 50 mm and 500 mm, e.g., 100 mm and 250 mm, e.g., about 150 mm.

[0013] In a preferred set of embodiments, the magnetic plate is substantially flat (e.g., substantially planar), e.g., over a majority of the surface area of ​​the magnetic plate. Preferably, the outer and / or inner surfaces are substantially planar, e.g., substantially planar. Preferably, the outer and inner surfaces are substantially parallel to each other.

[0014] The magnetic plate (e.g., inner and outer surfaces) can have any suitable and desired shape. Preferably, the shape of the outer surface is substantially the same as the shape of the inner surface. Preferably, the magnetic plate (e.g., outer and / or inner surfaces) is substantially circular. Preferably, the magnetic plate (e.g., outer and / or inner surfaces of the magnetic plate) has one or more (e.g., curved, e.g., corrugated, e.g., semicircular) indentations around the periphery of the magnetic plate. The overall circular shape of the magnetic plate helps make the docking structure more compatible with various types of capture mechanisms, and the indentations help to position and retain the magnetic plate within the docking structure.

[0015] In one set of embodiments, the magnetic plate includes a step around at least a portion of the periphery of the magnetic plate. Providing a step on the magnetic plate can aid in locating and retaining the position of the magnetic plate within the housing. Preferably, the step includes at least a portion of the outer surface of the magnetic plate that is adjacent to the periphery of the magnetic plate and extends in a direction away from the center of the magnetic plate (e.g., in a direction perpendicular to the center of the magnetic plate) (towards the satellite to which the docking structure is attached).

[0016] Thus, preferably, at least a portion of the outer surface of the magnetic plate adjacent the periphery of the magnetic plate faces outwardly from the center of the magnetic plate, e.g., in a direction perpendicular to the center of the magnetic plate, and similarly, preferably, at least a portion of the inner surface of the magnetic plate adjacent the periphery faces inwardly toward the center of the magnetic plate, e.g., in a direction perpendicular to the center of the magnetic plate.

[0017] In one set of embodiments, the magnetic plate includes a lip around at least a portion of the periphery of the magnetic plate. Providing a lip on the magnetic plate helps to locate and retain the magnetic plate within the housing, e.g., instead of or in addition to a step. Preferably, the lip comprises at least a portion of the magnetic plate that extends away (e.g., radially outward) from a central portion of the magnetic plate proximal to the periphery of the magnetic plate (e.g., in a direction parallel to the central portion of the magnetic plate). Preferably, the lip of the magnetic plate is outboard (e.g., radially) of the step of the magnetic plate.

[0018] Thus, in one preferred set of embodiments, the magnetic plate includes a (e.g. Z-shaped) step and a lip around at least a portion of the periphery of the magnetic plate. Preferably, the lip extends from the step towards the periphery of the magnetic plate (e.g. in a direction perpendicular to the step of the magnetic plate). Preferably, the step extends between a centre of the magnetic plate and the lip of the magnetic plate (e.g. in a direction perpendicular to the centre of the magnetic plate).

[0019] Preferably, the surface area of ​​the step and / or lip is (eg, significantly) smaller than the surface area of ​​the center (on the outer and / or inner surface) of the magnetic plate.

[0020] The magnetic plate is made of (e.g. made of) a soft magnetic material. Preferably, the magnetic plate includes or consists of a ferromagnetic material. Preferably, the magnetic plate includes or consists of a non-permanent magnetic material. Preferably, the magnetic plate has a low (e.g. substantially zero) remanent magnetic dipole, e.g., the magnetic plate does not generate a magnetic field itself but can be attracted by a magnetic field.

[0021] These magnetic properties of the magnetic plate serve to enable it to be captured (at least partially magnetically) by another spacecraft, but also to prevent it from interfering with the navigation system of the satellite to which the docking structure is attached.

[0022] In one embodiment, the magnetic plate is made of or consists of iron, such as an iron alloy, such as steel, such as Hyperco (RTM) 50, VACOFLUX (RTM) 50, or Permendur 49.

[0023] A housing of the docking structure is arranged to mount and restrain the magnetic plate, and the housing extending around at least a portion of the outer and inner surfaces of the magnetic plate is desirably arranged to be captured (e.g., contacted) by a capture mechanism of another spacecraft (either as part of the docking structure or a portion thereof).

[0024] The housing can have any suitable and desired shape. In a preferred embodiment, the housing surrounds a circular perimeter, e.g., the perimeter of the magnetic plate. This outer circular shape of the housing helps to match the docking structure with different types of capture mechanisms, and the indentations help to locate and retain the position of the housing within the docking structure.

[0025] Preferably, the housing has a shape complementary to that of the magnetic plate to mount and retain the magnetic plate. Preferably, the housing includes an opening and an outer surface (e.g., a central portion) of the magnetic plate is mounted within the opening of the housing. This allows the magnetic plate to be accessed (e.g., by a capture mechanism) through the opening (e.g., the outer surface of the magnetic plate), for example to facilitate magnetic attraction.

[0026] Preferably, the housing comprises an outer rim (e.g., defining an opening) arranged to retain the magnetic plate, e.g., to substantially prevent the magnetic plate from moving in a direction parallel and / or perpendicular to an outer surface of the magnetic plate. Preferably, the outer rim projects inwardly from a periphery of the housing, e.g., toward a central portion of the outer surface of the magnetic plate, e.g., in a direction parallel to the outer surface of the magnetic plate.

[0027] Preferably, for example, the housing (at the outer rim) comprises one or more (e.g. curved, e.g. semicircular shaped) protrusions, which are arranged to hold the magnetic plate, for example when the magnetic plate has one or more (e.g. curved, e.g. wavy, e.g. semicircular shaped) indentations at the periphery of the magnetic plate. Preferably, the one or more protrusions correspond to the one or more (e.g. curved, e.g. wavy, e.g. semicircular) (e.g. aligned) indentations at the periphery of the magnetic plate. Preferably, the one or more protrusions extend inwardly from the periphery of the housing, for example towards a central portion of the outer surface of the magnetic plate, for example in a direction parallel to the outer surface of the magnetic plate.

[0028] In these embodiments, the geometry of the housing serves to increase (eg, maximize) the exposed surface area of ​​the magnetic plate, which serves to improve capture of the docking structure.

[0029] The housing can have any suitable and desired dimensions as needed to accommodate the size and mass of the satellite to be mounted. Preferably, the largest dimension (e.g., diameter) of the housing is substantially the same as the largest dimension (e.g., diameter) of the magnetic plate, e.g., due to the housing extending around the periphery (e.g., outer rim) of the magnetic plate.

[0030] Thus, in one embodiment the housing (e.g. outer rim) has a maximum dimension (e.g. diameter) of between 50mm and 500mm, such as between 100mm and 250mm, e.g. between about 150mm. Preferably the housing (base plate or combined base plate and outer rim) has a thickness (orthogonal to the plane of the magnetic plate) of between 5mm and 50mm, such as between 10mm and 30mm, e.g. between 15mm and 25mm, e.g. between about 20mm.

[0031] Thus, at least in preferred embodiments, the housing has a thickness that is greater than the thickness of the magnetic plate, hi some embodiments, the housing (and, e.g., the magnetic plate) has an overall shape that is substantially (e.g., low) circular.

[0032] The housing may mount the magnetic plate in any suitable manner desired, hi one embodiment, the housing includes a base plate adjacent an inner surface of the magnetic plate, for example, on which the magnetic plate is mounted. Preferably, the base plate of the housing is substantially parallel to the magnetic plate (e.g., the inner surface of the magnetic plate). Preferably, the base plate extends over (e.g., substantially all of) the inner surface of the magnetic plate. Preferably, the base plate extends over an area that is greater than or the same size as the inner surface of the magnetic plate.

[0033] The housing can restrain the magnetic plate in any suitable and desired manner. In one embodiment, the housing includes a groove that receives at least a portion of the periphery of the magnetic plate. The groove aids in positioning and retaining the magnetic plate, and therefore aids in mounting and restraining the magnetic plate within the housing, and can negate the need to use any adhesive to retain the magnetic plate. Preferably, the groove comprises an annular groove.

[0034] Preferably, the groove extends (e.g., circumferentially) around the peripheral inwardly facing surface of the housing. Preferably, the groove has a depth (e.g., a dimension of the groove extending in a direction perpendicular to the direction in which the groove extends (circumferentially) around the housing) that extends at least partially parallel (e.g., radially) to the magnetic plate (e.g., the outer and / or inner surface of the magnetic plate), e.g., from near the center of the magnetic plate (the center of the groove opening) to away from the center of the magnetic plate (the base of the groove). Preferably, the groove has a depth that extends at least partially in a direction perpendicular to (e.g., axially to) the magnetic plate (e.g., from the outer surface (at the opening of the groove) to the inner surface (at the base of the groove).

[0035] Preferably, the groove has a depth that extends at an angle between 30 degrees and 60 degrees, e.g., between 40 degrees and 50 degrees, e.g., about 45 degrees (e.g., on the outer and / or inner surface) from the outer surface (the opening of the groove) closer to the center of the magnetic plate to the inner surface (the base of the groove) further away from the center of the magnetic plate.

[0036] In one embodiment, a groove is formed in an outer rim of a housing. Preferably, said groove is formed between said base plate and said outer rim of said housing. Preferably, said base plate and said outer rim of said housing overlap to form a groove.

[0037] In a preferred embodiment, the base plate and outer rim of the housing are formed as separate parts that are attached together to form the housing. In this embodiment, the shape of these separate parts (the base plate and outer rim of the housing) is preferably such that a groove is formed between the base plate and the outer rim when they are attached together to form the housing. Thus, preferably, the base plate of the housing includes at least a portion of the groove and / or the outer rim of the housing includes at least a portion of the groove.

[0038] In one embodiment, the magnetic plate is fixed to the housing (e.g., of the base plate). Preferably, the docking structure comprises one or more fasteners (e.g., bolts or screws) that connect the magnetic plate to the housing (e.g., of the base plate). Preferably, the magnetic plate (e.g., in the center) comprises an opening through which the fastener extends to couple the magnetic plate to the housing (e.g., the base plate). The fastener acts, for example together with a groove, to restrain the magnetic plate.

[0039] In one embodiment, the magnetic plate (e.g., an inner surface) contacts (e.g., rests on) a housing (e.g., of a base plate). The entire inner surface can contact the housing, but preferably the housing (e.g., of a base plate) includes one or more protrusions that contact the magnetic plate (e.g., inner surface).

[0040] The one or more protrusions can have any suitable desired shape. Preferably, the one or more protrusions include one or more ridges. Preferably, the ridges protrude from the housing (e.g., of the base plate) in a direction perpendicular to the magnetic plate (e.g., inner surface). Preferably, the one or more ridges extend on the housing (e.g., of the base plate) in a direction parallel to the magnetic plate (e.g., inner surface). The one or more ridges are one or more (e.g., multiple) concentric ridges, e.g., concentric with the center of the housing (e.g., base plate) (and thus preferably concentric with the center of the magnetic plate) and / or concentric with each other (if the housing includes multiple concentric ridges).

[0041] The base plate and outer rim of the housing can be attached (e.g., connected) together in any suitable and desired manner to form the housing. In one embodiment, the housing includes one or more fasteners (e.g., screws or bolts) for connecting the base plate to the outer rim. The one or more fasteners are preferably located around the periphery of the housing.

[0042] Preferably, the connection between the base plate and the outer rim acts to sandwich (e.g. clamp) the magnetic plate (e.g. in a groove) between the base plate and the outer rim, and therefore preferably the (e.g. primary) connection between the base plate and the outer rim of the housing, and thus the method of attaching and restraining the magnetic plate, does not use adhesives.

[0043] The housing may be made (e.g., comprised or consist of) any suitable and preferred material. In one embodiment, the housing comprises or consists of, for example, an iron alloy, for example, steel, for example, stainless steel, for example, grade 410 stainless steel, for example, 410S21 stainless steel. Preferably, the housing consists of aluminum, for example, an aluminum alloy, for example, 7075 aluminum alloy, for example, 7075-T6 aluminum alloy. Aluminum (and its alloys) are light and rigid and therefore well suited to provide structural strength to the support elements of a structure in a weight efficient manner.

[0044] In one embodiment, the docking structure includes a resilient (e.g., flexible, e.g., deformable, e.g., compressible) body of material between at least a portion of the housing and the magnetic plate. This helps to accommodate some tolerance between the magnetic plate and the housing, to accommodate differences in thermal expansion, e.g., due to the magnetic plate and the housing being made of different materials, and / or to provide some cushioning for the magnetic plate during launch. In one embodiment, the resilient body of material is between the base plate and the magnetic plate. In one embodiment, the resilient body of material is between the outer rim and the magnetic plate. In one embodiment, the resilient body of material is in a groove between the magnetic plate and (e.g., the outer rim and / or the base plate of the housing).

[0045] The resilient body of material may, for example, be used to suspend the magnetic plate within the housing without the magnetic plate contacting (eg, the outer rim and / or base plate of the housing). However, in one embodiment (e.g., as described above), in addition to a docking structure that includes a resilient material between at least a portion of the housing and the magnetic plate, a portion of the magnetic plate is in contact with a portion of the housing (e.g., the outer rim and / or the base plate).

[0046] The resilient body of material can be provided in any suitable and desired form, in one embodiment the resilient body of material comprises one or more O-rings, e.g., in a groove between the magnetic plate and the housing (e.g., the outer rim and / or the base plate), e.g., between the outer rim and the magnetic plate, e.g., of the housing (e.g., the base plate).

[0047] In one embodiment, the body of resilient material comprises, for example, one or more pads or (e.g., annular) rings between the housing (e.g., base plate) and the magnetic plate. When the housing (e.g., of the base plate) comprises one or more protrusions that contact the magnetic plate, the body of resilient material is preferably disposed between the one or more protrusions, for example within a recess defined between the one or more protrusions. In an embodiment in which the one or more protrusions comprise one or more concentric ridges, it is desirable for the body of resilient material to comprise one or more annular pads disposed between the one or more (e.g., multiple) concentric ridges.

[0048] The elastic body of material may be made of (e.g., consist of or consist of) any suitable and desired material. In one embodiment, the elastic body of material includes or consists of silicone rubber, such as space grade silicone (suitable for the space environment).

[0049] The docking structure may be arranged to be attached to (or formed as part of) the satellite in any suitable and desired manner. In one embodiment, the docking structure is formed as (e.g., an integral) part of the satellite. However, preferably, the docking structure is a separate structure (e.g., formed separately) that is then attached to the satellite.

[0050] In one embodiment, a housing of the docking structure may be used to attach the docking structure to the satellite, for example, the housing may be arranged to attach directly to the satellite. In these embodiments, the docking structure may be mounted flush with (e.g., embedded in) the surface of the satellite. The docking structure may be mounted such that the magnetic plate is flush with the surface of the satellite.

[0051] In one embodiment, the docking structure includes an attachment member connected to the housing for attaching the docking structure to the satellite. Preferably, the attachment member is attached to and extends away from a portion of the housing adjacent the inner surface of the magnetic plate. Thus, the housing may serve to attach the attachment member for attaching the docking structure to the satellite, as well as to attach and restrain the magnetic plate.

[0052] The attachment member may take any suitable and desired form. In one embodiment, the attachment member comprises one or more (preferably a plurality, e.g., six) posts extending from the housing for attaching the docking structure to the satellite. Preferably, the plurality of posts connect to the housing via a plurality, e.g., three, attachment points. Preferably, two or more (e.g., a pair of) posts connect to the housing at each attachment point.

[0053] Preferably, the attachment member includes a plurality of (e.g., three) attachment points for attaching the docking structure to the satellite. Preferably, two or more (e.g., a pair of) struts connect at each attachment point for attaching the docking structure to the satellite.

[0054] In a preferred embodiment, a plurality of struts extend between an attachment point on the housing and an attachment point for attaching the docking structure to the satellite. Preferably, the plurality of struts extend between these attachment points in a zigzag configuration, for example, a pair of struts extending from a common attachment point to different attachment points on the housing for attaching the docking structure to the satellite, and / or a pair of struts extending from a common attachment point to different attachment points on the housing for attaching the docking structure to the satellite. Such an arrangement has been found to be structurally robust and useful for balancing forces that may be transferred to the satellite during capture of the docking structure, for example.

[0055] The mounting members (e.g., masts) may have any suitable and desired dimensions. In one embodiment, the mounting members are positioned to space the housing and / or magnetic plate from the satellite by a distance (e.g., the mounting members have a dimension from where the mounting members are attached to the housing to the attachment point where they are attached to the satellite) of between 5mm-250mm, e.g., 50mm-200mm, e.g., 120mm-180mm, e.g., about 140mm or 160mm. This distance may, for example, correspond to the length of the mast.

[0056] In one embodiment, the docking structure does not include an attachment member connected to the housing. Instead, the docking structure (e.g., of the housing) may be arranged to be directly connected to (e.g., recessed within) the surface of the satellite. For example, the docking structure (e.g., the housing of the docking structure) may include one or more fastening members (e.g., bolts or screws) for coupling the housing to the satellite.

[0057] In one embodiment, the docking structure (e.g., the housing and / or the magnetic plate) includes one or more fiducial markers that identify the docking structure, help it be located by an acquiring satellite, and help the acquiring satellite orient itself relative to the docking structure. Preferably, the fiducial markers are located on an outer surface of the magnetic plate and / or on the periphery (e.g., outer rim) of the housing.

[0058] The fiducial markers may be positioned in any suitable and desirable manner. In one embodiment, the docking structure includes a plurality of fiducial markers, the plurality of fiducial markers being of a plurality of different shapes and / or sizes, e.g., having a plurality of different maximum dimensions. Providing fiducial markers of different shapes and / or sizes helps the docking structure to be identified and positioned at a plurality of different distances (e.g., ranges) away from the docking structure.

[0059] In one embodiment, one of the fiducial markers (of the plurality of fiducial markers) substantially surrounds the other fiducial markers, e.g., two or more fiducial markers are nested within one another. Desirably, two or more fiducial markers (of the plurality of fiducial markers) are concentrically positioned with respect to one another (i.e., share a common center point). Preferably, one or more of the plurality of fiducial markers (e.g., surrounding, e.g., coaxially with one another) comprise a (e.g., regular) polygon, e.g., a square. Preferably, one or more of the plurality of fiducial markers comprise a circle.

[0060] In a preferred embodiment, the magnetic plate comprises two (or more) rectangular concentrically arranged reference markers and two (or more, e.g. three or four) circular reference markers, e.g. outside the rectangular reference markers. Preferably, the rectangular concentrically arranged reference markers comprise an inner rectangle within the outer rectangle. Preferably, the inner rectangle comprises a filled rectangle. Preferably, the outer rectangle comprises a square ring, e.g. with a ring of constant width around the rectangular ring.

[0061] Preferably, one or more (eg, polygonal (eg, rectangular)) fiducial markers include a (eg, geometric) pattern (eg, surface decoration within a polygon). This can be used to help determine the orientation and / or location of the fiducial markers, and thus the docking structure, relative to the capturing spacecraft. In one embodiment, one or more (e.g., polygonal (e.g., rectangular)) fiducial markers include an ArUco marker. Preferably, an inner rectangle includes an ArUco marker.

[0062] Preferably, the pattern and / or geometry of the one or more fiducial markers (e.g., polygonal (e.g., rectangular) is arranged to allow the orientation and / or position of the magnetic plate (e.g., relative to the capture spacecraft) to be determined. Preferably, both sides of the outer rectangle (e.g., rectangular ring) include a gap (e.g., extending across the width of the rectangular ring). This preferably forms four linked "L" shapes which, with a gap between each "L" shape, make up the rectangular ring. Preferably, the gaps on either side of the rectangle are arranged such that there are two or more "L" shaped shapes, with the two legs of each "L" shape having different proportions of length.

[0063] This helps ensure that the "L" shape can be arranged in a unique rotated configuration, allowing a spacecraft capturing the docking structure (such as a computer vision system) to determine the orientation and / or position of the magnetic plates relative to the captured spacecraft. Additionally, the orientation and / or position can be determined independent of the relative angle between the magnetic plate and the capture spacecraft (eg, a computer vision system).

[0064] The fiducial markers can be provided in any suitable and desired manner. In one embodiment, the docking structure includes a (e.g., thin) outer layer including one or more of the fiducial markers, where the outer layer is attached to an outer surface of the magnetic plate and / or to the periphery (e.g., outer rim) of the housing. Preferably, an inner (e.g., polygonal) fiducial marker is disposed on the outer layer.

[0065] Preferably, the outer reference marker (e.g., circular) comprises a cap for a fastener used to connect the base plate of the housing to the outer rim of the housing. Thus, the outer reference marker (e.g., circular) is preferably threaded onto the fastener. Preferably, the fastener is threaded into one or both of the base plate and the outer rim, and thus the outer reference marker is not necessarily used to hold the base plate and the outer rim of the housing together.

[0066] Preferably, one or more of the fiducial markers are reflective, for example to incident laser light. The circular fiducial markers (for example those located outside the rectangular fiducial markers) are preferably reflective.

[0067] Preferably, one or more of the fiducial markers are non-reflective. Preferably, the polygonal (e.g., rectangular) fiducial markers are non-reflective, e.g., to the incident laser light. The use of reflective and non-reflective fiducial markers can help provide both long-range and short-range fiducial patterns. For example, a reflective fiducial marker (e.g., circular) allows the docking structure to be detected from a longer distance (e.g., due to its reflectivity), while a non-reflective (e.g., polygonal) fiducial marker, e.g., a patterned rectangle, allows more information about the docking structure (e.g., its orientation and / or position) to be detected (and the orientation and / or determined position) at a closer distance.

[0068] The arrangement of the fiducial markers is believed to be novel and inventive in itself. Viewed from a further aspect therefore, the present invention provides a magnetic plate for a satellite including a plurality of fiducial markers for detection by a remote spacecraft, the plurality of fiducial markers comprising: one or more reflective fiducial markers for reflecting incident light from a remote spacecraft; one or more fiducial markers having a geometric shape and / or pattern for determining the orientation and / or position of the magnetic plate relative to a remote spacecraft; Here, one or more reflective fiducial markers are configured to be detected by the remote spacecraft from a distance between the remote spacecraft and the magnetic plate that is greater than the distance between the remote spacecraft and the magnetic plate at which the shapes and / or patterns of other fiducial markers are configured to be detected.

[0069] This aspect of the invention may include one or more (e.g. all) of the desirable and optional features outlined herein with respect to the other aspects and embodiments of the invention, and is preferred in that it includes the other aspects of the invention.

[0070] The docking structure may be used with (i.e., attached to) any suitable and desired type of satellite. Similarly, the docking structure may be arranged to be captured by (a capture mechanism of) a spacecraft of any suitable and desired type. The docking structure may be arranged to be captured (gripped) magnetically and / or mechanically, for example, with magnetic plates and / or mechanically around a housing (e.g., an outer rim of the housing).

[0071] The captured spacecraft preferably includes a capture mechanism arranged to capture, e.g., magnetically and / or mechanically, the docking structure. Preferably, the captured spacecraft (e.g., comprising a computer vision system) is arranged to identify and / or determine the orientation and / or position of the docking structure. Preferably, the captured spacecraft (e.g., comprising thrusters) is configured to position and orient the captured spacecraft relative to the docking structure and arranged to position and orient the capture mechanism relative to the docking structure, e.g., to enable magnetically and / or mechanically capturing the docking structure. [Brief description of the drawings]

[0072] Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: [Figure 1] 1 is a perspective view of a docking structure for attachment to a satellite in accordance with one embodiment of the present invention; [Diagram 2] FIG. 2 is an exploded view of the magnetic plate and housing of the docking structure shown in FIG. 1. [Figure 3a] 3 shows a cross-sectional view of the docking structure shown in FIGS. 1 and 2. FIG. [Figure 3b] 3 shows a cross-sectional view of the docking structure shown in FIGS. 1 and 2. FIG. [Figure 4] 2A-2B show different perspective views of the docking structure shown in FIGS. 1, 2, 3a and 3b; [Diagram 5] FIG. 5 shows another perspective view of the docking structure shown in FIGS. 1, 2, 3a, 3b and 4. [Figure 6] FIG. 6 shows how the docking structure shown in FIGS. 1, 2, 3a, 3b, 4 and 5 is attached to a satellite. [Figure 7] FIG. 6 illustrates how the docking structures shown in FIGS. 1, 2, 3a, 3b, 4 and 5 can be captured by another spacecraft. [Figure 8]FIG. 6 illustrates how the docking structures shown in FIGS. 1, 2, 3a, 3b, 4 and 5 can be captured by another spacecraft. [Figure 9] 1 is a perspective view of a docking structure for attachment to a satellite, according to one embodiment of the present invention; [Figure 10] 10 illustrates an exploded view of the magnetic plate and housing of the docking structure shown in FIG. 9. [Figure 11a] 11 shows a cross-sectional view of the docking structure shown in FIGS. 9 and 10. FIG. [Figure 11b] 11 shows a cross-sectional view of the docking structure shown in FIGS. 9 and 10. FIG. [Figure 12a] 11 shows a cross-sectional view of the docking structure shown in FIGS. 9 and 10. FIG. [Figure 12b] 11 shows a cross-sectional view of the docking structure shown in FIGS. 9 and 10. FIG. [Figure 13] FIG. 13 is another perspective view of the docking structure shown in FIGS. 9, 10, 11a, 11b, 12a and 12b. [Figure 14] 14 shows another perspective view of the docking structure shown in FIGS. 9, 10, 11a, 11b, 12a, 12b and 13. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0073] The thousands of satellites and other objects orbiting above Earth contribute to a large amount of "space junk" that can cause problems for other (e.g., operational) satellites when such satellites or objects are no longer needed. Attaching a docking structure to a satellite and using it to capture the satellite from another spacecraft allows such a satellite to be manipulated, for example, to remove it from orbit so that it does not become space junk, to relocate it to a different orbit, or to perform in-orbit servicing.

[0074] Described below are embodiments of a docking structure that can be attached to a satellite to enable capture of the satellite by another spacecraft (ie, any air vehicle operating in a space environment).

[0075] 1 shows a perspective view of a docking structure 1 for attachment to a satellite according to an embodiment of the present invention. The docking structure 1 comprises a magnetic plate 2, a housing 4, and a mounting member 6 for attaching the docking structure 1 to a satellite.

[0076] The magnetic plate 2 is made from Hyperco (RTM) 50 steel, a magnetically soft ferromagnetic material. The magnetic plate 2 is attached to and constrained by a housing 4. The housing 4 is made from 7075-T6 aluminum alloy. A mounting member 6, also made from 7075-T6 aluminum alloy, is connected to the opposite side of the housing 4. The mounting member 6 includes three attachment points 8 for attaching the docking structure 1 to the satellite.

[0077] Figure 2 shows an exploded view of the magnetic plate 2 and housing 4 of the docking structure 1 shown in Figure 1. The housing 4 includes two main components: a base plate 10 and an outer rim 12. The base plate 10 and the outer rim 12 are connected together by bolts 14 that pass through the periphery of the base plate 10 and the outer rim 12, respectively. When connected together by the bolts 14, the base plate 10 and the outer rim 12 act to sandwich the magnetic plate 2 within the housing 4.

[0078] 2, the docking structure 1 also includes a silicone rubber disk 16 (made of space grade silicone rubber) between the base plate 10 of the housing 4 and the magnetic plate 2, and a pair of silicone rubber O-rings 18 (made of space grade silicone rubber), one O-ring 18 between the base plate 10 of the housing 4 and the magnetic plate 2, and the other O-ring 18 between the outer rim 12 of the housing 4 and the magnetic plate 2. The silicone rubber disk 16 and silicone rubber O-ring 18 act to retain the magnetic plate 2 within the housing and provide some tolerance between the various components, for example to allow for differential thermal expansion.

[0079] 2 also shows that the magnetic plate 2 has a generally circular shape with wavy recesses 20. The outer rim 12 of the housing 4 has wavy projections 22 that correspond to and mate with the recesses 20 of the magnetic plate 2. The O-ring 18 is shaped to follow the contour of the magnetic plate 2.

[0080] Figures 3a and 3b show cross-sectional views of the docking structure 1 shown in Figures 1 and 2. Figure 3b is an enlarged portion of Figure 3a.

[0081] The cross-sectional views of Figures 3a and 3b show how the base plate 10 and outer rim 12 of the housing 4 sandwich the magnetic plate 2. The bolts 14 that hold the base plate 10 and outer rim 12 of the housing 4 together pass through the base plate 10 and thread around the outer rim 12 within the wavy projections 22 of the outer rim 12.

[0082] As can be seen most clearly in Figure 3b, the magnetic plate 2 includes a Z-shaped step and a lip around the perimeter of the magnetic plate 2. The base plate 10 and outer rim 12 of the housing 4 are shaped to form an angled groove 26 in the housing 4. O-rings 18 are positioned in angled grooves 26 on either side of magnetic plate 2 to suspend the step and lip of magnetic plate 2 within grooves 26 and capture magnetic plate 2 within the housing. A silicone rubber disk 16 between base plate 10 of housing 4 and magnetic plate 2 helps suspend magnetic plate 2 within housing 4.

[0083] FIG. 3a also shows that the mounting member 6 connects to and screws into the base plate 10 of the housing 4 via three mounting points 28 (only one of which is visible in FIG. 3a) with a bolt passing through each mounting point 28.

[0084] Figure 4 shows a different perspective view of the docking structure 1 shown in Figures 1, 2, 3a and 3b. From this angle, three attachment points 28 for connecting the mounting member 6 to the base plate 10 of the housing 4 are visible. The mounting member 6 has six posts 30, two of which meet at each attachment point 28. Two posts 30 also meet at each of the attachment points 8 for attaching the docking structure 1 to the satellite. The six posts 30 thereby form a zigzag configuration for the mounting member 6.

[0085] FIG. 4 also shows bolts 14 which pass through the base plate 10 of the housing 4 and thread around the outer rim 12 to hold the housing 4 together.

[0086] Figure 5 shows another perspective view of the docking structure 1 shown in Figures 1, 2, 3a, 3b and 4. The docking structure 1 is shown with a cover 32 over the magnetic plate 2 and the housing 4. The cover 32 has a number of fiducial markers 34, 36, 38 formed thereon. The fiducial markers 34, 36, 38 include a central rectangle 34, an outer corner ring 36, and three circles 38.

[0087] The circular fiducial marker 38 is formed from a reflective material. The central rectangle 34 is made of an ArUco marker. The outer rings 36 have gaps on either side of the ring to form four "L" shapes, three of which have different aspect ratios for the leg lengths of each "L" shape.

[0088] The fiducial markers 34, 36, 38 help the docking structure 1 to be identified and located by the acquisition satellite and help the acquisition satellite orient itself relative to the docking structure 1. The different shapes and sizes of the fiducial markers 34, 36, 38 help the docking structure 1 to be identified and located at various ranges of distances away from the docking structure 1.

[0089] Figure 6 illustrates how the docking structure 1 is attached to a satellite 40 (a "client" spacecraft) in one embodiment of the present invention. As shown in Figure 6, the docking structure 1 is bolted to the satellite 40 via attachment points 8 at the tips of the posts 30 of the attachment members 6. This spaces the magnetic plate 2 and housing 4 of the docking structure 1 away from the surface of the satellite 40. However, it will be appreciated that in some embodiments the docking structure 1 may not include attachment members 6, and instead the housing may be directly connected (e.g., recessed) to the surface of the satellite 40.

[0090] 7 illustrates, in one embodiment of the present invention, how the docking structure 1 is captured by another "servicer" spacecraft 50. The "servicer" spacecraft 50 has a magnetic head 51 (mounted on satellite 40) that is positioned relative to magnetic plate 2 of the docking structure 1, such that magnetic head 51 is aligned with magnetic plate 2, as shown in FIG.

[0091] As the "servicer" spacecraft 50 approaches the docking structure 1, the magnetic head 51 acts to attract the magnetic plate 2, causing the magnetic head 51 to connect to the magnetic plate 2. Once the docking structure 1 is attached to the "servicer" spacecraft 50 (via the magnetic plate 2 being connected to the magnetic head 51), the "servicer" spacecraft 50 can then manipulate, as necessary, the satellite 40 to which the docking structure 1 is attached.

[0092] Figure 8 illustrates, in one embodiment of the present invention, how docking structure 1 is captured by another "servicer" spacecraft 50. The "servicer" spacecraft 50 has a mechanical head 52 that is positioned relative to the housing 4 of docking structure 1 (mounted on satellite 40) such that mechanical head 52 is aligned with housing 4, as shown in Figure 8.

[0093] When the "servicer" spacecraft 50 approaches the docking structure 1, the mechanical head 52 is used to mechanically grab the housing 4, causing the housing 4 to connect to the mechanical head 52. Once the docking structure 1 is attached to the "servicer" spacecraft 50 (via the housing 4 which is connected to the mechanical head 52), the "servicer" spacecraft 50 can then manipulate, as needed, the satellite 40 to which the docking structure 1 is attached.

[0094] Another docking structure according to an embodiment of the present invention, similar to the docking structure shown in FIGS. 1 to 5, will now be described with reference to FIGS.

[0095] 9 shows a perspective view of a docking structure 101 for attachment to a satellite according to one embodiment of the present invention. The docking structure 101 includes a magnetic plate 102, a housing 104, and a mounting member 106 for attaching the docking structure 101 to a satellite.

[0096] The magnetic plate 102 is made from Hyperco (RTM) 50 steel, a magnetically soft ferromagnetic material. The magnetic plate 102 is mounted and constrained on a housing 104. The housing 104 is made from 7075-T6 aluminum alloy. Four reflective circular fiducial markers 138 are positioned around the periphery of the housing 104.

[0097] Also connected to the opposite side of the housing 104 is an attachment member 106, fabricated from 7075-T6 aluminum alloy. The attachment member 106 includes three attachment points 108 for attaching the docking structure 101 to a satellite.

[0098] Figure 10 shows an exploded view of the magnetic plate 102 and housing 104 of the docking structure 101 shown in Figure 9. The housing 104 includes two main components: a base plate 110 and an outer rim 112. The base plate 110 and the outer rim 112 are coupled together by bolts 114 that pass through the periphery of the base plate 110 and the outer rim 112, respectively. When connected together by the bolts 114, the base plate 110 and the outer rim 112 act to sandwich the magnetic plate 102 within the housing 104.

[0099] 10 also shows that the docking structure 1 includes four concentric silicone rubber rings 116 (made from space grade silicone rubber) between the base plate 110 of the housing 104 and the magnetic plate 102. The silicone rubber rings 116 are positioned between concentric circular ridges in the base plate 110 and act to hold the magnetic plate 102 within the housing 104, provide some tolerance between the various components, and absorb vibrations, for example, during satellite launch.

[0100] 10 also shows that the magnetic plate 102 has a generally circular shape with wave-shaped indentations 120. The outer rim 112 of the housing 104 has protrusions 122 that correspond to and mate with the indentations 120 of the magnetic plate 102.

[0101] The magnetic plate 102 has a central opening 124 through which a bolt 125 passes. The bolt 125 passes through a corresponding opening 127 in the base plate 110 and is fastened with a nut 129.

[0102] Figures 11a, 11b, 12a and 12b show cross-sectional views of the docking structure 101 shown in Figures 9 and 10. Figure 11b is an enlarged portion of Figure 11a and Figure 12b is an enlarged portion of Figure 12a.

[0103] The cross-sectional views of Figures 11a and 11b show how the base plate 110 and the outer rim 112 of the housing 104 are connected together by bolts 114 that pass through the periphery of the base plate 110 and the outer rim 112, respectively. When the base plate 110 and the outer rim 112 are connected together by the bolts 114, they act to sandwich the magnetic plate 102 within the housing 104. The bolts 114 that hold the base plate 110 and the outer rim 112 of the housing 104 together pass through the base plate 110 and thread around the periphery of the outer rim 112 within the wavy projections 122 of the outer rim 112.

[0104] 11 a and 11 b also show that a reflective circular reference marker 138 is threaded to form a cap on the top of the bolt 114 .

[0105] FIG. 11a also shows that the mounting member 106 is connected to the base plate 110 of the housing 104 via three mounting points 128 (only one of which is visible in FIG. 11a) with a bolt passing through each mounting point 128 and screwing into the base plate 110 of the housing 104.

[0106] The cross-sectional views of Figures 12a and 12b show how the base plate 110 and outer rim 112 of the housing 104 sandwich the magnetic plate 102 therebetween.

[0107] As can be seen most clearly in Figure 12b, the magnetic plate 102 includes a Z-shaped step and a lip at the periphery of the magnetic plate 102. The base plate 110 and outer rim 112 of the housing 104 are shaped to form grooves 126 in the corners of the housing 104 that correspond to the Z-shaped step and lip of the magnetic plate 102. A silicone rubber ring 116 between the base plate 110 of the housing 104 and the magnetic plate 102 helps cushion the magnetic plate 102 on the base plate 110 of the housing 104.

[0108] Figure 13 shows a different perspective view of the docking structure 101 shown in Figures 9, 10, 11a, 11b, 12a and 12b. From this angle, the three attachment points 128 for connecting the attachment members 106 to the base plate 110 of the housing 104 are visible. The attachment members 106 have six posts 130, two of which meet at each attachment point 128. Also, two posts 130 meet at each of the attachment points 108 for attaching the docking structure 101 to the satellite. The six posts 130 thus form a zigzag configuration for the attachment members 106.

[0109] Figure 13 also shows a bolt 114 that passes through the base plate 110 of the housing 104 and threads around the outer rim 112 to hold the housing 104 together. Figure 13 further shows a nut 129 that is used to tighten the bolt that passes through central openings in the magnetic plate 102 and base plate 110 to connect the magnetic plate 102 and base plate 110 to one another.

[0110] Figure 14 shows another perspective view of the docking structure 101 shown in Figures 9, 10, 11a, 11b, 12a, 12b and 13. The docking structure 101 is shown with a cover 132 over the magnetic plate 102 and the housing 104. The cover 132 has a number of fiducial markers 134, 136, 138 formed thereon. The fiducial markers 134, 136, 138 include a central rectangular portion 134, outer corner rings 136, and four circles 138.

[0111] The circular fiducial marker 138 is formed from a reflective material. The central rectangle 134 is made of ArUco markings. The outer rings 136 form four "L" shapes with gaps on either side of the ring, three of which have different aspect ratios for the leg lengths of each "L" shape.

[0112] The fiducial markers 134, 136, 138 help the docking structure 101 to be identified and located by the acquisition satellite and help the acquisition satellite orient itself relative to the docking structure 101. The different shapes and sizes of the fiducial markers 134, 136, 138 help the docking structure 101 to be identified and located at different ranges of distances from the docking structure 101.

[0113] It will be understood that the docking structure 101 shown in Figures 9-14 may be used as shown in Figures 6-8, attached to a satellite 40, and captured by the capture system of a "servicer" spacecraft 50 in a manner similar to that described for the docking structure 1 shown in Figures 1-5.

[0114] Thus, in at least a preferred embodiment, the docking structure of the present invention is constructed and the most suitable materials are selected for the housing and magnetic plate to allow the housing and magnetic plate to be decoupled from each other, which helps to increase the mechanical robustness and durability of the docking structure and to reduce the effects of thermal cycling, which can be extreme in space, on the various components of the docking structure.

[0115] The capture of a satellite by the magnetic plates can be used for one of a number of operations, including, but not limited to, removing the satellite from orbit, relocating the satellite to another orbit, and performing in-orbit or off-orbit servicing of the satellite.

Claims

1. A docking structure for a satellite, comprising: a magnetic plate; and a housing for mounting and restraining the magnetic plate, wherein the magnetic plate includes an outer surface and an inner surface, the magnetic plate includes a soft magnetic material, the housing extends around at least a part of the periphery of the magnetic plate, extends over at least a part of the outer surface of the magnetic plate, and extends over at least a part of the inner surface of the magnetic plate, and the docking structure is characterized by mounting and restraining the magnetic plate.

2. The docking structure according to claim 1, wherein the magnetic plate comprises steps around at least a part of the periphery of the magnetic plate.

3. The docking structure according to claim 1 or 2, wherein the magnetic plate comprises lips around at least a part of the periphery of the magnetic plate.

4. The docking structure according to claim 1, wherein the magnetic plate comprises steps and lips around at least a part of the periphery of the magnetic plate, and the lips extend from the steps towards the periphery of the magnetic plate.

5. The docking structure according to claim 1 or 2, wherein the magnetic plate includes a non-permanent magnetic material.

6. The docking structure according to claim 1 or 2, wherein the housing includes an opening, and the outer surface of the magnetic plate is mounted in the opening of the housing.

7. The docking structure according to claim 1 or 2, wherein the housing comprises an outer rim arranged to hold the magnetic plate and a base plate adjacent to the inner surface of the magnetic plate.

8. The docking structure according to claim 7, wherein the outer rim projects inwardly from the periphery of the housing.

9. The docking structure according to claim 7, wherein the housing comprises one or more fasteners for connecting the base plate to the outer rim.

10. The docking structure according to claim 1 or 2, wherein the housing comprises a groove for receiving at least a part of the periphery of the magnetic plate.

11. The docking structure according to claim 1 or 2, wherein the housing comprises a groove formed between the base plate and the outer rim of the housing, and the groove receives at least a part of the periphery of the magnetic plate.

12. The docking structure according to claim 1 or 2, comprising one or more fasteners for connecting the magnetic plate to the housing.

13. The docking structure according to claim 1 or 2, wherein an inner surface of the magnetic plate is in contact with a base plate of the housing.

14. The docking structure according to claim 13, wherein the base plate of the housing comprises one or more protrusions that contact the inner surface of the magnetic plate.

15. The docking structure according to claim 14, wherein the one or more protrusions include one or more ridges.

16. The docking structure according to claim 15, wherein the one or more ridges include one or more coaxial ridges.

17. The docking structure according to claim 1 or 2, wherein the docking structure comprises an elastic material body between at least a part of the housing and the magnetic plate.

18. The docking structure according to claim 17, wherein the base plate of the housing includes one or more protrusions that contact the inner surface of the magnetic plate, and the elastic material body is disposed between the one or more protrusions.

19. The docking structure according to claim 1 or 2, wherein the docking structure comprises a mounting member connected to the housing for attaching the docking structure to a satellite.

20. The docking structure according to claim 1 or 2, comprising one or more reference markers.

21. The docking structure according to claim 20, comprising a plurality of reference markers, the plurality of reference markers having a plurality of different shapes and / or sizes.

22. The docking structure according to claim 21, wherein one of the reference markers substantially surrounds another reference marker.

23. The docking structure according to claim 21, wherein the magnetic plate comprises a plurality of reference markers arranged coaxially and a plurality of circular reference markers.

24. The docking structure according to claim 20, wherein one or more of the reference markers include a pattern and / or one or more of the reference markers are reflective.

25. A magnetic plate for a satellite, comprising a plurality of reference markers for detection by a remote spacecraft, the plurality of reference markers comprising one or more reflective reference markers for reflecting light incident from a remote spacecraft Comprising one or more reference markers having a geometry and / or pattern for determining the direction and / or position of a magnetic plate relative to a remote spacecraft, wherein the one or more reflective reference markers are configured to be detected by a remote spacecraft from the distance between the remote spacecraft and the magnetic plate, the distance being longer than the distance between the remote spacecraft and the magnetic plate configured such that the geometry and / or pattern of the other reference markers are detected, a magnetic plate characterized thereby.

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