DEPLOYABLE REFLECTOR

Abstract

A deployable reflector is configured to transition from a stowed position to a deployed position, passing through various intermediate positions characterized by peaks and valleys, achieving a paraboloid shape when fully deployed. The reflector includes a central polygonal section, which takes the form of an n-sided polygon, and is supported by a set of 2n radial sections. These radial parts extend from the central polygon and widen towards the outer edge. The radial sections are connected by folds that originate from the vertices of the central polygon and extend outward. These folds are arranged so that in the intermediate positions, the valleys alternate with peaks. When the reflector is in its deployed position, the radial sections form a quadratic surface. On the non-reflective side of the radial folds, there are backing elements made from a material that is more elastic than that of the radial parts.

Claims

1. A deployable reflector, configured to change from a stowed position to a deployed position with intermediate positions with peaks and valleys, and paraboloid shaped when deployed, wherein it comprises the following parts: a central polygonal part, in the form of an n-sided polygon, a set of 2n radial parts starting from the central polygonal part and widening towards the periphery, so that the radial parts are joined by radial folds starting from the vertexes of the central polygonal part towards the periphery, the folds being arranged in such a way that the folds which in the intermediate positions are valleys alternate with the folds which in the intermediate positions are peaks, the radial parts having a quadratic surface when the reflector is in its deployed position, and backing elements on a non-reflective side of the radial folds in the peak/valley positions, made in a material more elastic than that of the radial parts, wherein the backing elements are configured to allow the folding of the radial parts together when stowed, wherein the set of 2n radial parts has a peripheral edge of polygonal shape with n sides, the deployable reflector additionally comprising a frame with n sides attached to the sides of the peripheral edge of the set of 2n radial parts and having a hinged angular link between every two adjacent sides of the frame.

2. The deployable reflector, according to claim 1, further comprising a fixed central element over the central polygonal part, around which the radial parts may unfurl to stow and deploy the reflector.

3. The deployable reflector, according to claim 2, wherein the fixed central element holds a telescopic boom.

4. The deployable reflector according to claim 1, further comprising motors at each hinged angular link between every two adjacent sides of the frame.

5. The deployable reflector according to claim 1, wherein the deployable reflector has an offset focal point 2.

Description

DESCRIPTION OF FIGURES

[0022] FIG. 1 shows a perspective view of a deployable reflector, with its surface fully deployed and showing its field of view.

[0023] FIG. 2 shows a perspective view of a deployable reflector, with its surface fully deployed and showing its field of view.

[0024] FIG. 3 shows the different elements that form the deployable reflector of FIG. 1.

[0025] FIG. 4 shows the deployable reflector of FIG. 1 and its reflective surface.

[0026] FIG. 5 shows the deployable reflector of FIG. 1 in an intermediate position.

[0027] FIG. 6 shows the deployable reflector of FIG. 1 in a deployed position.

[0028] FIG. 7 shows the deployable reflector of FIG. 2 in a deployed position with a central core and showing its field of view.

[0029] FIG. 8 shows the deployable reflector of FIG. 1 in a deployed position in a configuration with an external perimeter frame and showing its field of view.

[0030] FIG. 9 shows the deployable reflector of FIG. 1 in a stowed position and with a central core.

[0031] FIG. 10 shows the deployable reflector of FIG. 1 in an intermediate position and with a central core.

[0032] FIG. 11 shows the deployable reflector of FIG. 1 in a deployed position and with a central core.

[0033] FIG. 12 shows the deployable reflector of the invention in a stowed position with an external perimeter frame.

[0034] FIG. 13 shows the deployable reflector of the invention in an intermediate position with an external perimeter frame.

[0035] FIG. 14 shows the deployable reflector of the invention in a deployed position with an external perimeter frame.

DETAILED DESCRIPTION OF THE INVENTION

[0036] FIGS. 1, 3, 4 and 6 show one embodiment of a deployable reflector, with its surface fully deployed. The reflector has a reflective side 1 and a non-reflective side.

[0037] The deployable reflector is paraboloid shaped when deployed and configured to change from a stowed position to a deployed position with intermediate positions (see, for instance the sequence of FIGS. 9 to 11, and the sequence of FIGS. 12 to 14). The intermediate positions have peaks and valleys (see FIG. 5), that correspond to peak folding lines (folds 6) and valley folding lines (folds 7) in the surface fully deployed of the deployable reflector (see FIG. 6).

[0038] The deployable reflector of FIG. 1 comprises the following parts: [0039] a central polygonal part 5, in the form of an n-sided polygon (in this case, a hexagon, i.e. n=6), [0040] a set of 2n radial parts 3, 4 (12 radial parts in this embodiment) starting from the central polygonal part 5 and widening towards the periphery, so that the radial parts 3, 4 are joined by radial folds starting from the vertexes of the central polygonal part towards the periphery, the folds 6, 7 being arranged in such a way that the folds 7 which in the intermediate positions are valleys alternate with the folds 6 which in the intermediate positions are peaks, the radial parts 3, 4 having a quadratic surface when the reflector is in its deployed position, and [0041] backing elements on a non-reflective side of the radial folds 6, 7, made in a material more elastic than that of the radial parts 3, 4.

[0042] FIG. 1 shows the focal point 2 and the field of view 10 of this deployable reflector.

[0043] FIGS. 2 and 7 show a deployable reflector in which the set of 12 radial parts has a peripheral edge in the shape of a circumference. FIG. 2 shows the focal point 2 and the field of view 10 of this deployable reflector.

[0044] It is to be noted that the deployable reflector of FIG. 7 has a centered focal point 2, while the deployable reflector of FIG. 8 has an offset focal point 2. The spacecraft 8 from which the reflector deploys is shown in FIG. 8 and the following ones.

[0045] The deployment process of the invention follows the Miura unfolding, regardless the fact of being quadratic radial parts 3, 4 instead of planar ones. These radial parts 3, 4 behave like flexible membranes that deploy whilst unrolling around the central polygonal part 5, as it can be seen in FIGS. 9-11 or FIGS. 12-14.

[0046] This type of unrolling of the radial parts 3, 4 can fit with two deployable reflector configurations: [0047] with a fixed central element, around which the radial parts 3, 4 unfurl to unfold. In this case the focal antenna can be deployed with a telescopic boom 9, held by the fixed central element and accommodated inside the empty inner volume over the central polygonal part 5, when stowed (FIGS. 9-11). [0048] inside an external perimeter frame 11, that deploys with the radial parts 3, 4 (FIGS. 12-14). The frame 11 has n sides (6, in this embodiment) attached to the sides of the peripheral edge of the set of 2n radial parts 3, 4 (12, in this embodiment) and having a hinged angular link between every two adjacent sides of the frame 11.

[0049] In the embodiment of FIGS. 12-14 there may be motors at each hinged angular link between every two adjacent sides of the frame 11.

[0050] The folding of the radial parts 3, 4 (quadratically shaped) is possible thanks to the following factors: [0051] high elasticity of the materials of the radial parts 3, 4, capable to deform without yielding. [0052] low thickness of these radial parts 3, 4, to minimize the stresses. [0053] curved sections of the surface become almost straight line when submitted to the bending loads in the stowed accommodation.

[0054] The exact origami pattern depends on the thickness and number of radial parts 3, 4, as it must be conceived to allow a folded stress-free configuration. A thickness-accommodating origami pattern requires adaptation of the crease design to account for thickness of the radial parts 3, 4, giving a slight apparent curvature in some of the folding lines in the deployed pattern as result (thicker radial parts will require higher curvature in the folding lines).

[0055] The resulting radial parts 3, 4 will require a backing element in peak/valley positions (considerably more elastic than the radial parts 3, 4 of the reflector) to allow their folding together when stowed.

[0056] The design of the reflector of the invention is inspired in the Miura origami fold, but deploying a 3D design (quadratic surfaces) instead of 2D one. With this pattern, quadratic surface subdivision can be minimized attaining very compact stowed volumes that can be deployed in orbit into large reflective surfaces.

[0057] This Miura fold also simplifies the unfolding process once in orbit, as it is a single degree of freedom synchronous deployment with very few nodes, compared to other origami-inspired patterns.

[0058] Such high compaction of the sectors is possible thanks to the use of current high-elasticity composite thin radial parts 3, 4, that recover their natural quadratic shape in a stress free configuration when deployed (they are originally conformed to this shape).

[0059] When the origami is unfolded, its radial parts reach their stress-free configuration, being all the paraboloid in its minimum energy state. As a consequence, deformation on the radial parts 3, 4 will motorize the deployment until reaching a non-reversible deployed configuration.

[0060] 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.