Assembly apparatus

The present invention relates to an assembly apparatus for assembling components of spacecraft in space. The assembly apparatus includes: a core platform; and a mobile platform including an end effector configured to perform an assembly or manufacturing task. The mobile platform is connected to the core platform by a tether. The core platform includes a body and a coupling element connected to and extendable from the body such that the coupling element may be spaced from the body of the core platform. The tether connects the mobile platform to the body via the coupling element. The assembly apparatus further includes an actuator configured to vary the length of the tether extending between the coupling element and the mobile platform to control the position of the mobile platform relative to the body of the core platform.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and is a 35 U.S.C. § 371 U.S. National Stage Application of International Application No. PCT/GB2021/050078, entitled “AN ASSEMBLY APPARATUS”, filed Jan. 13, 2021, which claims priority to European Application No. 20275010.5, entitled “AN ASSEMBLY APPARATUS”, filed Jan. 15, 2020, the contents of each being incorporated by reference herein in its entirety.

TECHNICAL FIELD OF THE INVENTION

The technical field of the present invention is assembly manufacturing apparatuses. More specifically, the technical field of the present invention is assembly apparatus for the assembly of components of spacecraft in space.

BACKGROUND OF THE INVENTION

Placing spacecraft into space is a complex task in which an increase in mass of the spacecraft to be placed into space can dramatically increase the cost of the operation. Furthermore, the spacecraft must also fit within given dimensions of the launch vehicle which carries the spacecraft to space. Thus, spacecraft with large dimensions or which require, for example, large solar arrays or antennae have two options for fitting within the payload volume of the launch vehicle.

The first option is to design foldable and/or deployable parts of the spacecraft so that the spacecraft can be in a retracted state until placed in space at which time it can deploy into its extended, operational state. However, these foldable and/or deployable parts are complex to design and build, and also increase the weight of the spacecraft, thus increasing the cost to launch.

The second option is to complete the assembly of the spacecraft once the spacecraft is in space. However, known apparatuses rely on robots which move along spacecraft structures using multiple arms like spider or monkey. The arms of these robots are highly complex and require multiple degree of freedom systems, i.e. at least 3 per arm. Thus, there is an inherent risk of wear and failure for each mechanism over the time period of the manufacture operation. Some known apparatuses use a free-flyer to move around a workspace. However, these flyers require a significant amount of fuel and malfunction of the flyer can result in destruction of the spacecraft and/or loss of the flyer.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an advantageous assembly apparatus for assembling and/or manufacturing components of spacecraft in space.

In accordance with embodiments of the invention described herein, there is provided an assembly apparatus for assembling or manufacturing components of spacecraft in space, the assembly apparatus comprising: a core platform; and a mobile platform comprising an end effector configured to perform an assembly task; the mobile platform being connected to the core platform by a tether; the core platform comprising a body and a coupling element connected to and extendable from the body such that the coupling element may be spaced from the body of the core platform; wherein the tether connects the mobile platform to the body via the coupling element; and an actuator configured to vary the length of the tether extending between the coupling element and the mobile platform to control the position of the mobile platform relative to the body of the core platform.

The assembly apparatus may further comprise a deployable truss configured to space the coupling element from the body of the core platform when deployed.

The assembly apparatus may comprise a plurality of deployable trusses and a plurality of tethers, the coupling element being located on distal end of each truss when deployed and being configured to receive a tether to connect the mobile platform to the core platform.

Preferably, the body of the core platform is a central body and the plurality of trusses are extendable outwardly from the central body.

The assembly apparatus may comprise at least one separate tether coupled to the each coupling element at a coupling point, the coupling point of each truss defining a workspace of the apparatus when the truss is deployed.

In some embodiments, the plurality of trusses may form a three-dimensional frame when deployed which defines a workspace in which the mobile platform can be moved in each of the three dimensions.

The assembly apparatus may further comprise an actuator for each tether so that the lengths of the tethers extending between the coupling points and the mobile platforms can be varied independently in order to position the mobile platform in any position in the workspace.

In some embodiments, the assembly apparatus may further comprise an additional tether extending directly between the body of the core platform and the mobile platform and an additional actuator to control the length of the additional tether.

The actuators may be located on the body of the core platform. Preferably, the actuators may be located on the coupling elements located at the distal end of the trusses of the core platform when the trusses are deployed. Alternatively, the actuators may be located in the mobile platform.

The end effector may comprise a robotic manipulator, the robotic manipulator being configured to perform an assembly or manufacturing task.

In some embodiments, the body of the core platform may comprise a storage compartment for storing structural elements of a spacecraft to be assembled and/or repaired.

In accordance with another aspect of the invention, there is provided a system for assembling a component of a spacecraft in space, the system comprising: an assembly apparatus as defined by claim1; and a plurality of structural elements of a component of a spacecraft to be assembled.

In accordance with another aspect of the invention, there is provided a method of assembling a component of a spacecraft in space using an assembly apparatus as defined by claim1, the method comprising: placing the assembly apparatus in space; deploying a truss to extend from the body of the core platform; adjusting the length of the tether extending between the mobile platform and the coupling element at the distal end of the truss to position the mobile platform proximate to the body; using an end effector on the mobile platform to acquire a structural element from a storage compartment on the body of the core platform; actuating the actuator to vary the length of the tether extending between the mobile platform and the coupling element at the distal end of the truss to position the mobile platform in a specified position relative to the body of the core platform; and placing the structural element in the specified position relative to the body of the core platform using the end effector.

DETAILED DESCRIPTION OF THE INVENTION

Referring toFIG.1, an embodiment of an assembly apparatus1for assembling a component of a spacecraft2, an example of which is shown inFIG.11, in space is shown. The assembly apparatus1may be configured to complete assembly of itself once it has been delivered into space in a partially assembled state. The assembly apparatus1may also be configured to assemble at least components of other spacecraft2once the assembly apparatus1is fully assembled. The assembly apparatus1may also be configured to carry out repairs on itself or other spacecraft.

The assembly apparatus1comprises a core platform3and a mobile platform4. The mobile platform4comprises an end effector5which in the present embodiment is a robotic manipulator, shown inFIG.3. The robotic manipulator5is configured to carry out an assembly task on a spacecraft2or a component of a spacecraft2, including the assembly apparatus1, as will be described in more detail hereinafter. It will be appreciated that in alternative embodiments, the end effector5may be, for example, but not limited to a device capable of performing at least one of the following operations: manipulation, joining, 3D printing, cutting, forming, etc.

The mobile platform4is connected to the core platform3by a tether6. The core platform3comprises a body7and a truss8extending from the body7. The truss8comprises a distal end9spaced from the body7of the core platform3. The tether6connects the mobile platform4to the body7via the distal end9of the truss8. One function of the tether6is to prevent the mobile platform4being lost into space in the event of a malfunction which reduces space debris.

The truss8is shown inFIG.1in its deployed state. However, in order to fit within a launch vehicle (not shown), the truss8may be a deployable, machined, or assembled truss8. That is, the truss8may originally be in an undeployed state when the assembly apparatus1is launched into space. Referring briefly toFIG.2, the truss8of the core platform3can be seen in its undeployed state.

In this example, the truss8is extended from the main body7of the core platform3when the assembly apparatus1is in space by telescopically extending the truss8from the body7. However, it will be appreciated that the truss8may be deployed by other means, for example, but not limited to, by unfolding the truss8, by being assembled from elementary parts, i.e. units, or by 3D printing, i.e. manufacturing, the truss8in situ.

The assembly apparatus1further comprises an actuator11. InFIG.1, the actuator11is shown located at the distal end9of the truss8. However, in an alternative embodiment, the actuator11may be located in a different position on the assembly apparatus1. For example, in one embodiment, the actuator11may be located in the mobile platform4, as shown inFIG.3. In another example, the actuator11may be located in the body7of the core platform3.

In each embodiment, the actuator11is configured to vary the length of the tether6extending between the distal end9of the truss8and the mobile platform4. Preferably, the assembly apparatus1comprises an actuator11for each tether6. The length of the tether6is used to determine the position of the mobile platform4relative to the body7of the core platform3, as will be explained in more detail hereinafter.

The actuator11may comprise a motor12configured to rotate a spindle13about which a tether6can be wound and unwound. By driving the motor12so that the tether6is wound about the spindle13, the length of the tether6extending between the core platform3and the mobile platform4can be reduced. By driving the motor so that the tether6is unwound from the spindle, the length of the tether6extending between the core platform3and the mobile platform4can be increased.

In the present embodiment, the assembly apparatus1comprises a plurality of trusses8. The present embodiment also comprises a plurality of tethers6. Preferably, the assembly apparatus1comprises at least as many tethers6as it does trusses8. Additionally, the spacecraft assembly apparatus1preferably comprises an actuator11associated with each truss8, that is, at least one actuator11per truss8, so that each of the at least one tether6associated with a truss8is actuated by an actuator11that is independent of actuators11associated with other trusses8. Therefore, the assembly apparatus1may comprise an actuator11for each tether6. In this way, the mobile platform4can be moved in a greater number of directions and can move over a larger area, as will be explained in more detail hereinafter. In some embodiments, the distal end9of each truss8is configured to receive at least one of the plurality of tethers6to connect the mobile platform4to the core platform3.

In addition to the body7, the core platform3comprises a coupling element15. The coupling element15is connected to and extendable from the body7such that the coupling element15may be spaced from the body7of the core platform3.

Preferably, a tether6is coupled to the distal end9of each truss8by a coupling element15. That is, the assembly apparatus1comprises at least one tether6coupled to the distal end9of each truss8by a coupling element15. Furthermore, each tether6is coupled at one end to an actuator11, as previously mentioned, and is connected at its other end to an anchor point16on the core platform3, either on the body7or on a truss8, or on the mobile platform4. More than one tether6per truss8may be used to provide redundancy for the assembling apparatus1. In addition, to provide further redundancy, each tether6on the same truss8may have its own actuator11.

In the embodiment, shown inFIG.1, the coupling element15for the tether6is on the distal end9of the truss8. However, in the present embodiment, the coupling element15is formed by the actuator11. That is, the actuator11is located at the distal end9of the truss8and is connected to the tether6. Thus, each of the tethers6only extend between an actuator11at the distal end9of a truss8and an anchor point16on the mobile platform4

However, it will be appreciated that in alternative embodiments, when the actuator11is located on the body7of the core platform3, the coupling element15may comprise a pulley (not shown) configured to provide a pivot or turning point for a tether6which extends between the actuator11on the body7of the core platform3and the mobile platform4. Thus, in such an embodiment, a tether6would extend from the body7of the core platform3along the truss8to the coupling element15at the distal end9of the truss8and then back to the mobile platform4.

In another alternative embodiment, in which the actuator11is located on the mobile platform4of the assembly apparatus1, as shown most clearly inFIG.3, the anchor point16may either be on the body7of the core platform3with a coupling element15at the distal end9of the truss8or the anchor point16may be the coupling element15at the distal end9of the truss8, as shown inFIG.3.

An advantage of having the actuator11or the anchor point16at the coupling element15, i.e. having the actuator11or the anchor point16at the distal end9of the truss8, is that it reduces the length of the tether6that is required by the assembly apparatus1.

The coupling element15, whether formed by an actuator11, an anchor point16, or pulley, may be capable of rotating to face coupling element15on the end of other trusses8to facilitate movement of the mobile platform4. That is, the coupling element15may be rotatable so that the tether6which extends between the coupling element15and the mobile platform4is able to extend in a straight line. This helps to avoid the tether6scraping against the edge of the actuator11or pulley17as the tether6is wound and/or unwound from the spindle13and so reduces wear of the tether6.

The coupling element15of each truss8defines a workspace18in which the mobile platform4can operate or perform a task such as assembling a component to be connected to itself, assembling a component for another spacecraft, repairing a component of an existing spacecraft, and/or manufacturing a component. The workspace18is defined by the coupling elements15, which form the vertices of the workspace18, and the straight line between adjacent coupling elements15. The coupling element15and the straight lines between them define the workspace18because they represent the limits to which the actuators11on the trusses8can move the mobile platform4. The larger the number of trusses8, the larger the area of the workspace18for a given length of truss8.

As shown inFIG.1, the core platform3of the assembly apparatus1of the presently described embodiment is a central body21. Furthermore, each of the plurality of trusses8extends outwardly from the central body21. In the present embodiment, each of the trusses8extends radially outwards from the central body21when viewed from above and are equally spaced about the longitudinal axis A of the central body21. Each truss8shown inFIG.1extends in a straight line so that the coupling elements15form the vertices of a hexagon, thus defining a hexagonal workspace18.

The central body21comprises side walls22. The side walls17are arranged around the longitudinal axis A of the central body21. In the present embodiment, each side wall22has a truss8extending therefrom. As shown inFIG.1, the present embodiment of the assembly apparatus1comprises six trusses8which extend from the six side walls22of the central body21in the radial direction. Therefore, the central body21has a hexagonal cross-section with six side walls22.

However, it will be appreciated that in an alternative embodiment, the central body21of the core platform3of the assembly apparatus1may have a different number of side walls22and therefore a different shaped cross-section. Furthermore, it will be appreciated that the number of trusses8may be different to the above described embodiment. It will also be apparent that the number of trusses8may be different to the number of side walls22of the central body21.

In the present embodiment, the mobile platform4also comprises a body23formed by six side walls24. Thus, the body23of the mobile platform4has a hexagonal cross section. InFIG.1, the tethers6are anchored at an anchor point16on vertices25of the mobile platform4. However, it will be appreciated that in other embodiments, the anchor point may be on the side wall24of the mobile platform24.

The mobile platform4is moved around within the workspace18by operating the actuators11on the distal end9of each truss8independently from one another. Therefore, whilst some of the actuators11are winding their associated tether6about the spindle13of the actuator11, other actuators11may be unwinding the associated tether6from their spindle13in order to allow movement of the mobile platform4. As a result, by varying the length of the tethers6between the distal ends of the trusses8and the mobile platform4independently using separate actuators11, the mobile platform4can be placed at any desired position within the workspace18.

For example, in the embodiment shown inFIG.1, the mobile platform4has been moved from its starting position in the centre of the workspace18to the position shown. In this example, the features such as tether6, trusses8, and actuators11will be referred to as first to sixth, denoted by letters a to f starting with the feature at the top of the page and moving clockwise for subsequent features.

In order to move the mobile platform4into the position shown inFIG.1from its starting central position, the first actuator11aand sixth actuator11fmust drive their motors12a,12fso that the length of the tethers6a,6fextending between the actuators11a,11fat the coupling elements15a,15fon the distal ends9a,9fof the first and sixth trusses8a,8fis reduced. As the mobile platform4is placed closer to the distal end9aof the first truss8athan the distal end of the sixth truss8f, the length of the first tether6abetween the distal end9aof the first truss8aand the mobile platform4is less than the length of the sixth tether6fbetween the distal end of the sixth truss8fand the mobile platform4.

Furthermore, as the mobile platform4has been positioned slightly towards the left side of the assembly apparatus1, the length of the second tether6bbetween the distal end9bof the second truss8band the mobile platform4is greater than the length of the sixth tether6fbetween the distal end9fof the sixth truss8fand the mobile platform4. Therefore, it is clear that positioning the mobile platform4within the workspace18is achieved by operating the actuators11independently to achieve different lengths of tether6extending from each distal end9of each truss8.

It will be appreciated that for the mobile platform4to have been moved from its central starting position to the position shown inFIG.1that the second, third, fourth and fifth actuators11b,11c,11d,11emust unwind their tethers6b,6c,6d,6efrom their spindles13b,13c,13d,13eto allow the length of the tethers6b,6c,6d,6ebetween the distal ends9b,9c,9d,9eof the second, third, fourth, and fifth trusses8b,8c,8d,8eto be increased. The tethers6may be unwound from their spindles13by driving the motors12in the opposite direction to the direction the motors12are driven to wind the tethers6onto the spindles13. Alternatively, the force of the other motors12winding their tethers6in may be used to unwind the wound tethers6.

Preferably, only the minimum length of tether6required extends between the distal end9of the truss8and the mobile platform4to allow the mobile platform4to be moved into any given position. That is, the tethers6may be kept taut. This enables the tethers6to accurately place the mobile platform4and ensures that small adjustments have an instant effect on the position of the mobile platform4. It also allows the mobile platform4to be kept in the same plane when moving around the workspace18and prevents rotation of the mobile platform.

Referring now toFIGS.2and3, perspective views of the assembly apparatus1in its undeployed state are shown, with the tethers6omitted for clarity. Furthermore, in the embodiment shown inFIGS.2and3, the actuators11can be seen to be located in side walls24of the mobile platform4.

As previously mentioned, the coupling element15is connected to and extendable from the body7such that the coupling element15may be spaced from the body7of the core platform3. That is because before and during launch the trusses8are yet to be deployed. Therefore, as shown inFIGS.2and3, before the trusses8are deployed, only the coupling elements15are located outside of the body7. Then, as the trusses8are deployed the coupling elements15are moved further from the body7.

The mobile platform4is located in its starting position in which it is located during launch or when an assembly process is about to begin or has finished. The starting position of the mobile platform4is above the body7of the core platform3. Once the assembly apparatus1is in space, the trusses8of the core platform3must be deployed. It can be seen fromFIG.3that in the present embodiment the distal end9of the trusses8are located outside the side walls22of the central body21before the trusses8are fully deployed.

As previously mentioned, the trusses8may be deployed from their retracted position by, for example, telescopically extending the trusses8in the radial direction. Another option is to deploy the trusses8by unfolding them from their retracted position. When unfolding the trusses8, the trusses8may be stored inside the mobile platform4or outside the mobile platform4such that they are aligned substantially parallel to the longitudinal axis A of the central body21of the core platform3. Each truss8may comprise multiple folded sections.

As a truss8is deployed, i.e. extended or unfolded, the actuator11associated with that truss8unwinds its tether6from the spindle13so that the mobile platform4may remain in its central starting position proximate to the central body21of the core platform3.

In an alternative embodiment, the trusses8may be 3D printed in situ. Therefore, the mobile platform4may comprise a 3D printer (not shown) configured to print sections of truss8which can then be assembled by the robotic manipulator5. In order to achieve this, one actuator11may reel its tether6in fully so that the mobile platform4is adjacent the anchor point16on the distal end9of a truss8. At this point, a section of a truss8can be printed and the robotic manipulator5can be used to attach the anchor point16to one end of the truss8and the other end of the truss8to the mobile platform4. This process can be repeated until the required workspace18has been created.

In a further alternative embodiment, the trusses8may be 3D printed in situ by a 3D printer located inside the core platform3. Individual units of the trusses8, i.e. a section of a truss8, may be printed and then extruded outwards. Therefore, the coupling element15remains at the end of the truss8and does not need to be moved by the robotic manipulator5.

Referring toFIG.2, the assembly apparatus1further comprises a storage compartment31. The storage compartment31is configured to store structural elements32of a component of a spacecraft to be assembled and/or repaired, as will be described in more detail hereinafter.

In the present embodiment, the storage compartment31is located radially outside of the side walls22of the central body21of the core platform3. As shown inFIG.2, the storage compartment31is made up of sections33a-33fwhich surround the central body21of the core platform3. Each section33of the storage compartment31is configured to store structural elements32to be placed proximate to the corresponding truss8extending from the side wall22proximate to which the section33of the storage compartment31is located. However, it will be appreciated that the sections33of the storage compartment31may vary in number and do not have to surround the central body21of the core platform3.

The storage compartment31is located on the opposite side of the trusses8to the mobile platform4so that the storage compartment31and structural elements32stored therein do not inhibit or obstruct movement of the mobile platform4around the workspace18. However, an end34of the storage compartment31is located such that it is within reach of the robotic manipulator5of the mobile platform4when the mobile platform4is above the storage compartment31in the direction parallel to the longitudinal axis A of the central body21.

Referring toFIG.3, it can be seen that the anchor point16on the coupling element15is located at the distal end9of the truss8. The anchor point16is located at a distance from the centre of the truss8. That is, the anchor point16is located at a distance from the axis of the truss8in the direction of the longitudinal axis A of the central body21of the core platform3. This is because the coupling element15comprises a projection36having a free end37. The anchor point16is located on the projection36. In the present embodiment, the projection36extends parallel to the longitudinal axis A of the central body21.

More specifically, the anchor point16is located at the free end37of the projection36. The anchor point16being located at the end37of the projection36raises the mobile platform4above the trusses8so that the mobile platform4can be move freely about the workspace18without contacting the trusses8.

Referring briefly now toFIG.4, the embodiment of the assembly apparatus1described above can be seen in perspective view with its trusses8fully deployed and the tethers6shown. It can be seen that the projection37allows the tethers6and therefore mobile platform4to be held clear of the trusses8to allow unhindered movement of the mobile platform4about the workspace18.

InFIG.4, the assembly apparatus1has partially completed assembly of a component of a spacecraft. It can be seen that the mobile platform4has been moved around the workspace18to position a number of structural elements32around the central body21of the core platform3. In the present embodiment, the structural elements32are hexagonal to maximise the use of space and are shown inFIG.4in solid blocks.

FIG.4also shows the workspace18in dotted lines which give an example of the potential positions in which further structural elements32can be placed by the mobile platform4. In the present embodiment, the trusses8extend radially from the central body21of the core platform3and all extend in the same plane. Therefore, the workspace18of the mobile platform4is planar, i.e. 2D, as is the array of structural elements32that are positioned by the mobile platform4.

Referring now toFIGS.5to10, a method of assembling a component of a spacecraft2using the assembly apparatus1described above will be discussed briefly.

FIG.5shows a zoomed in perspective view of a method step for assembling a component of a spacecraft2using the assembly apparatus1after the assembly apparatus1has been launched form earth in a launch vehicle and placed into its predetermined position in space. Furthermore, the method step show inFIG.5occurs after the trusses8of the assembly apparatus1have been deployed.

The step illustrated inFIG.5is adjusting the length of the tethers6extending between the mobile platform4and the distal end9of the trusses8to position the mobile platform4proximate to the body7,21of the core platform3. More specifically, each of actuators11is actuated to either wind the associated tether6around the spindle13or to unwind the associated tether6from the spindle13in order to position the mobile platform4to the body7,21of the core platform3.

As shown inFIG.5, the actuators11are actuated such that the mobile platform4is placed close enough to the body7,21of the core platform3to enable the robotic manipulator5to reach a structural element32stored in the storage compartment31. As shown inFIG.6, when the mobile platform4is correctly placed proximate to the storage compartment31, the robotic manipulator5is extended towards a structural element32. The robotic manipulator5may comprise a grabbing mechanism41on its free end which is configured to take hold of the structural element32. The robotic manipulator5is then retracted to remove the structural element32from the storage compartment31.

Referring now toFIG.7, each actuator11is again actuated to vary the length of the tethers6between the mobile platform4and the distal ends9of the trusses8in order to position the mobile platform4in a specific position relative to the body7,21of the core platform3. The specific position of that the mobile platform4is moved into by the actuators11may be predetermined. For example, the mobile platform4may be moved to a safe distance to perform the next step or may be moved into position to place the structural element32in its final position.

Referring toFIG.8, the structural element32that is held by the robotic manipulator5is opened up from its stored state into it deployed state. This may be actuated by the robotic manipulator5or by the structural element32itself.

In the present embodiment, the structural element32comprises a tile43of a sparse phased-array antenna44, shown inFIG.11. Each tile43comprises a deployable structure similar to an umbrella. A tile43may comprise a dipole46and electronic circuits47in its centre. Furthermore, the tile43, or any other structural element32, may comprise a mechanical link48at each vertex49. The mechanical link48is configured to connect neighbouring tiles together and tiles to the trusses8.

Referring toFIG.9, when the mobile platform4is in the correct position relative to the body7,21of the core platform3, the robotic manipulator5extends to precisely position the structural element32, or tile43, in its correct position relative to the truss8and any other structural elements32, or tiles43, that have already been placed in their assembled position. When the tile43is positioned in its correct assembled position by the robotic manipulator5, the mechanical link48secures the tile43to adjacent tiles43and/or the adjacent truss(es)8.FIG.10, shows top view of the mobile platform4placing a tile43into its assembled position.

The method of assembling is repeated until or the structural elements32, or tiles43, have been placed in their correct positions to make a fully assembled component of a spacecraft2, or as discussed in this example sparse phased array antenna, as shown inFIG.11.

Although the previous embodiments of the assembly apparatus1have been described in relation to a two-dimensional or planar workspace18, it will be appreciated that the assembly apparatus1may be configured such that the workspace18is three-dimensional. That is, the mobile platform4can be moved in all three dimensions. To achieve this, the trusses8may extend in different planes to create a workspace18of the mobile platform4which is three-dimensional and can be used to construct three-dimensional arrays with the assembly apparatus1. Furthermore, in some embodiments, a three-dimensional array may be constructed whilst using trusses8which extend in the same plane. The two above mentioned concepts will now be discussed in more detail.

Referring toFIG.12, a further embodiment of the assembly apparatus1is shown. The embodiment of the assembly apparatus1shown inFIG.12is generally the same as the embodiment of the assembly apparatus shown inFIGS.1to11and so a detailed description will be omitted. Furthermore, similar features and components of the assembly apparatus1will retain similar terminology and reference numbers.

The main difference between the embodiment of the assembly apparatus1shown inFIG.4, and the embodiment of the assembly apparatus inFIG.12is that the trusses8of the present embodiment do not all extend in the same plane. Referring to the schematic side view of the assembly apparatus1shown inFIG.12, a truss8extends from the side wall22of the central body21of the core platform3.

The truss8comprises a first section51and a second section52. The first section of the truss8forms an inboard section of the truss8which extends from the central body21of the core platform3. The second section52of the truss8forms an outboard section of the truss which extends from a distal end53of the first section51of the truss8. The first section51of the truss8extends from the central body21of the core platform3at an acute angle to the longitudinal axis A of the central body21. Therefore, the distal end53of the first section51of the truss8is raised from the perpendicular plane in which the trusses8of the first embodiment of the assembly apparatus1extend.

The second section52of the truss8extends at an acute angle to the first section51of the truss8. This creates a section of the truss8with a steeper angle compared to the angle created by the inclination of the first section51of the truss8. It will be understood that in some embodiments, the inclination of the first and second sections51,52of the truss8will be the same, that is, their longitudinal axis will be parallel, and that in some embodiments, the second section52of the truss8will be omitted.

As shown inFIG.12, each of the trusses8of the assembly apparatus8may comprises the inclined sections51,52. This enables the distal ends9of the trusses8to be spaced by a greater distance in the direction parallel to the longitudinal axis A from the central body21of the core platform3. However, the workspace18of the mobile platform4is still planar due to the tethers6being connected to the distal end9of the trusses8at the anchoring point16which forms the coupling element15.

In such an embodiment, the components of a spacecraft2assembled by the assembly apparatus1can still be built in three dimensions due to the reach of the robotic manipulator5. For example, as shown inFIG.12, a sparse phased array antenna44can be constructed having a parabolic shape by extending the gripping mechanism41by different distances from the mobile platform4when placing individual tiles43in their positions. For example, tiles43placed proximate to the periphery of the workspace18require the least extension of the robotic manipulator5, whereas tiles43placed at the centre of the workspace18require the largest extension of the robotic manipulator5.

In some instances, the length of the trusses8and thus size of the components of the spacecraft2, or antenna44, may be so large that the robotic manipulator5cannot extend the distance required to place structural elements32, or tiles43, proximate to the central body21of the core platform3.

Therefore, as shown inFIG.13, in order to move the mobile platform4close enough to the central body21of the core platform3, the assembly apparatus1may further comprise an additional tether56. The additional tether56extends between the main central body21of the core platform3and the mobile platform4. The additional tether56is connected at one end to an additional actuator57. The additional actuator57is configured to vary the length of the additional tether56extending between the central body21of the core platform3and the mobile platform4.

By driving the motor12of the additional actuator57to wind the additional tether56around the spindle13of the additional actuator57, the mobile platform4can be pulled towards the central body21of the core platform3and away from the plane in which each of the distal ends9of the trusses8are located. Therefore, the workspace18of the mobile platform4can be made three dimensional. That is, the mobile platform4can be moved in three dimensions to assemble a spacecraft2, or antenna44.

Referring briefly toFIG.14, another use of the assembly apparatus1is depicted. As shown, the assembly apparatus1may be used to deploy and manage payload elements61a-61d. In such an embodiment, the assembly apparatus1may comprise at least one truss8to which payloads61can be connected.

The truss8may comprise a first section51to which payloads can be connected and a second section52extending at an angle to the first section51which provides an anchor point16for a tether6.

The payloads61may be moved along the at least one truss8in a similar way to which the tiles43described above are deployed. That is, the mobile platform4is positioned above a payload, for example payload61c, and the robotic manipulator5is actuated to take hold of the payload61c. The actuators11can then be actuated to move the mobile platform4to its new position to reconnect the payload to the truss8.

Referring now toFIG.15, a schematic side view of another embodiment of the assembly apparatus1is shown. In this embodiment, the plurality of trusses8form a three dimensional frame64. The frame64forms a cage like structure in which the mobile platform4is moveable. The frame64is formed on one side of the body7of the core platform3. The core platform3also comprises a storage compartment31for storing structural elements32for assembling components of the spacecraft2in situ.

In the present embodiment, each vertex65where trusses8of the frame64meet comprises an anchor point16for a tether6. The other end of the tether6is attached to an actuator11on the mobile platform4. It will be appreciated that in alternative embodiments the anchor points16may be on the mobile platform4and the actuators11may be located at the vertices65.

Therefore, the plurality of trusses8form a three-dimensional frame64which defines a three-dimensional workspace in which the mobile platform4can be moved in each of the three-dimensions to assemble a component of a spacecraft2.