DEPLOYABLE ASSEMBLY FOR ANTENNAS

Abstract

A deployable assembly for antennae includes a structure having a reflective surface and n pairs of segments, each pair of segments corresponding to one side of a deployed polygonal shape. N hinge joints are between the two segments of a side. N hinged angular links are between every two adjacent sides. The structure is changeable from a stowed substantially cylindrical shape into a deployed substantially planar polygonal shape with n sides. A deployable boom is between two segments. The boom lays stowed between the two segments before deployment and ends in a feeder electromagnetically feeding the antenna and includes a clamping element for keeping the structure closed when stowed. The feeder acts as structural support element when stowed and electromagnetic feeder for the antenna when deployed. A cable network shapes the reflective surface, with corresponding cables held by tensor elements protruding from the back of the segments.

Claims

1. A deployable assembly for antennae, comprising: a structure comprising: n pairs of segments, each pair of segments corresponding to one side of a deployed polygonal shape, n hinge joints between the two segments of a side, and n hinged angular links between every two adjacent sides, wherein the structure is configured to change from a stowed position with a substantially cylindrical shape into a deployed position with a substantially planar polygonal shape with n sides, and a reflective surface, a deployable boom between two segments, wherein the deployable boom lays stowed between the two segments in the stowed position, a feeder on an end of the deployable boom, the feeder being configured to electromagnetically feed the antenna and comprises a clamping element for keeping the structure closed when stowed, wherein the feeder acts as a structural support element when stowed and electromagnetic feeder for the antenna when deployed, a set of tensor elements protruding from a back of the segments, and a cable network that can shape configured to shape the reflective surface, such that wherein the corresponding cables are held by the tensor elements.

2. A deployable assembly for antennae, according to claim 1, wherein the reflective surface is a paraboloid with circular contour.

3. A deployable assembly for antennae, according to claim 1, wherein the reflective surface is a paraboloid with elliptical contour.

4. A deployable assembly for antennae, according to claim 1, further comprising a set of brackets protruding from the back of the segments to shape the contour of the reflective surface.

5. A deployable assembly for antennae, according to claim 1, further comprising a lower clamping element.

6. A deployable assembly for antennae, according to claim 1, wherein the deployable boom is placed between two segments of a same side of the polygonal shape.

7. A deployable assembly for antennae, according to claim 1, further comprising motors at each hinged angular link between every two adjacent sides.

8. A deployable assembly for antennae, according to claim 1, further comprising latches to ensure non-reversibility of a final deployed position.

Description

DESCRIPTION OF FIGURES

[0044] FIG. 1 is an isometric view of a prior art large deployable reflector attached to a satellite.

[0045] FIGS. 2A, 2B and 2C are schematic overviews of the object of the invention in the stowed, deploying and fully deployed (operative) positions, respectively.

[0046] FIG. 3 is a more detailed view of the stowed assembly, in the launch configuration within the available volume of the fairing.

[0047] FIG. 4 shows the deployed assembly in the operative arrangement.

[0048] FIG. 5 is a simplified view of the stowed and the deployed assembly (feeder, boom, cable network and reflective surface not represented).

[0049] FIGS. 6A to 6F show the main steps of the deployment of the structure and the assembly.

[0050] FIG. 7 shows the deployable assembly of the invention in an intermediate position of the deployment process.

DETAILED DESCRIPTION OF THE INVENTION

[0051] FIGS. 2A, 2B and 2C show the deployable assembly for antennae of the invention in several stages. FIG. 2A shows the stowed position, FIG. 2B shows an intermediate position in which the assembly is being deployed, and FIG. 2C shows the fully deployed position.

[0052] FIGS. 6A to 6F also show the deployable assembly for antennae of the invention in several stages, with more intermediate positions.

[0053] FIG. 7 is a detailed view of the deployable assembly of the invention in an intermediate position of the deployment process, in which all of its elements can be seen.

[0054] The deployable assembly for antennae shown in these figures comprises: [0055] a structure comprising: [0056] n pairs of segments 4, 5, each pair of segments 4, 5 corresponding to one side of a deployed polygonal shape, [0057] n hinge joints between the two segments 4, 5 of a side, and [0058] hinged angular links 6 between every two adjacent sides, and [0059] a reflective surface 9.

[0060] The structure is configured to change from a stowed position with a substantially cylindrical shape into a deployed position with a substantially planar polygonal shape with n sides, as it can be seen in FIG. 5.

[0061] The deployable assembly for antennae also comprises: [0062] a deployable boom 3 between two segments 4, 5, wherein the deployable boom 3 lays stowed between the two segments 4, 5 in the stowed position, [0063] a feeder 1 on an end of the deployable boom 3, the feeder 1 being configured to electromagnetically feed the antenna and that comprises a clamping element 2 for keeping the structure closed when stowed, such that the feeder 1 plays the role of structural support element when stowed and electromagnetic feeder for the antenna when deployed, [0064] a set of tensor elements 8 protruding from the back of the segments 4, 5, and [0065] a cable network 7 that can shape the reflective surface 9, such that the corresponding cables are held by the tensor elements 8.

[0066] Preferably, the deployable boom 3 is placed between two segments 4, 5 of the same side of the polygonal shape, as it can be seen, for instance, in FIGS. 6B to 6F. The deployable boom 3 lies stowed, clamped and protected between two segments 4,5 before being deployed to meet the focal distance. FIGS. 6A to 6D show the successive steps for the formation of the polygonal shape with n sides, and FIGS. 6D to 6F show the deployment of the boom 3. In FIG. 6F the deployable assembly for antennae of the invention is completely deployed.

[0067] FIG. 5 is a simplified view of the deployable assembly of the invention mainly showing the structure, where the feeder 1, the boom 3, the cable network 7 and reflective surface 9 are not represented.

[0068] As indicated, the feeder 1 can play the role of: [0069] a fixation element for the segments 4,5 when stowed, by means of the clamping element 2 (see FIG. 3, for example), and [0070] an electromagnetic feeder for the antenna, when the feeder 1 is deployed.

[0071] The clamping element 2 can be, for instance, a clamp band similar to the ones used in similar applications in spacecraft systems.

[0072] The deployed polygonal shape has n sides, corresponding to the n pairs of segments 4, 5. In the figures that show an embodiment of the invention a hexagonal shape has been chosen (see, for example, FIG. 5). Each pair of segments is formed by two symmetric segments 4, 5, with a hinge joint as a linking element between them.

[0073] The deployable ring structure of the invention has enough room inside to hold the necessary spacecraft subsystems. It may contain everything needed to form a complete satellite, like power systems, flight and attitude control and communication with the Earth, though it can also be conceived as a payload, attached to a bigger satellite.

[0074] FIGS. 5 and 7 also show n hinged angular links 6 between every two adjacent sides of the polygonal shape, thus placed in each corner of the polygonal shape. The shape can be defined as a regular or non-regular polygon, in order to achieve a circular or elliptical contour of the reflective surface 9. FIGS. 5 and 7 also show a set of brackets 15 protruding from the back of the segments 4, 5 to shape the contour of the reflective surface 9.

[0075] The movement of the deployment of the structure is achieved by motors at each hinged angular link 6. The coordination can be guaranteed by mechanical means and/or position sensors as feedback signals when needed. The final position can be guaranteed by end-stops, and the non-reversibility of the final deployed configuration can be ensured with latches, if wished.

[0076] The cable network 7 comprises several tensioning cables to ensure that the reflective surface 9 meets its desired shape when deployed. As it can be seen in FIG. 7, the tensioning cables can be held by tensor elements 8 protruding from the back of the segments 4, 5, able of tensing the tensioning cables.

[0077] By means of this configuration a tensioned cable network 7 is obtained. Preferably the reflective surface 9 is a paraboloid formed by cables that work by traction, as previously described.

[0078] As for the contour of the reflective surface 9, it can be circular or elliptical.

[0079] The reflective surface 9 is folded, constrained and protected inside the stowed structure during launch (see FIGS. 3 and 6A). The stowed structure protects the reflective surface 9 from contacting and damaging the feeder 1.

[0080] FIG. 3 also shows a lower clamping element 10 (for instance, a clamp band) that stays with the launcher after separation. It also shows the available stowed height range 14 within the launcher, which defines the diameter of the reflective surface 9.

[0081] FIG. 5 also shows the minor axis 11 and the major axis 12 of the contour of the reflective surface 9 when it is elliptical. It also shows the diameter 13 of the structure in the stowed position.

[0082] The present invention represents a space closed loop deployable assembly with a structure able to change from a substantially cylindrical configuration into a substantially planar polygonal configuration having n sides: [0083] Holding tightly all the systems from launch till deployment, with the need of just two clamping elements 2, 10 (could be clamp bands). [0084] Deploying a wide range of reflector antennae, maintaining the same minimum amount of mechanisms. [0085] Accommodating all the systems traditionally contained in a service module (such as propulsion, power generation, navigation, etc) inside its deployable segments. [0086] Easing the design, analysis, manufacturing and Assembly Integration & Testing (AIT) tasks. [0087] Suitable for multiple purposes: [0088] Earth observation (Large Deployable Reflectors, radiometers, radars) [0089] Telecom [0090] Space debris capture [0091] Cluster of coordinated satellites launched together to reduce costs and sub-sequent space debris at the end of life. [0092] Building segments for larger space structures assembled in space

[0093] Although the present invention has been fully described in connection with preferred embodiments, it is apparent that modifications can be made within the scope, not considering this as limited by these embodiments, but by the content of the following claims.