Patent Description:
The deployable Space reflector according to the patent <CIT>, comprises peripheral support framework with two deployable peripheral polygonal rings consisting of interconnected rods, connecting rods of the rings providing a certain separation of the rings, a reflecting surface and a tensioning framework for shaping the reflecting surface, a deployment mechanism and a latching mechanism.

This reflector is characterized with a low stiffness and stability, while two polygonal rings and connecting rods of the rings form rectangular ring facets which need additional means for stiffening - diagonal rod or cables in the patent.

The other known deployable space reflector [<NPL>] comprises a peripheral support framework with two deployable peripheral polygonal rings of interconnected rods, and connecting rods of the rings providing a certain separation of the rings. One of the rings of the supporting framework has pair-wise hinged cross rods and the other ring interconnected hinged rods of V-fold rods.

This reflector is also characterized with a low stiffness and stability, while it has a row of the V-fold rods as one of the ring of the support peripheral framework. In addition, it is characterized with a non-compact stowed package, while the other ring of the framework has angulated cross rods and the V-fold rods fold inside of the package, which limits the folding. Complexity of reaching the deployed state of the V-fold rods is a characteristic drawback of the mentioned peripheral framework.

The deployable Space reflector according to the patent <CIT>, comprises a peripheral support framework with two deployable peripheral polygonal rings of interconnected rods, and connecting rods of the rings providing a certain separation of the rings, a reflecting surface and a tensioning framework for shaping the reflecting surface, a deployment mechanism and a latching mechanism.

This reflector is also characterized with drawbacks as a low stiffness and stability of the deployed configuration, as well as large height of the stowed package caused by such a folding scheme in which the height is a sum of the lengths of the ring rod and the connecting rod of the rings. This reflector is also characterized with complexity or even impossibility of reaching the large deployed sizes of the reflector. This drawback is a result of a presence of the tensioning framework, which has a shape of facetted double concave lens. Due to the character of the double concave lens, even if it has a near zero thickness at the center, it might reach larger heights at the periphery with large diameters, this fact limits the height of the reflector under the described concept to the small sizes.

The deployable Space reflector according to the "Concept of the Tension Truss Antenna", Koryo Miura and Yasuyuki Miyazaki, The Institute of Space and Astronautical Science, Yoshidai, Sagamihara, Kanagawa, Japan, AIAA Journal, vol. <NUM>, <IMG> <NUM>, which consists of a support framework, a reflecting surface, the tensioning framework forming the reflecting surface, a deployable and a latching mechanisms. The tensioning framework is made of front and rear cable networks, which are interconnected by flexible ties.

This reflector is characterized with similar drawbacks as the previous one, namely, low deployed stiffness and stability caused by the radial support frame, as well as large height of the stowed package of the reflector for large diameters. The latter one is caused again by the presence of the tensioning framework, which has a shape of facetted double concave lens.

<CIT> describes a deployable space reflector according to the preamble of claim <NUM>.

<CIT> describes deployable support structures, such as but not limited to large deployable apertures for space applications. A six-bar linkage structure is proposed as the lateral facet of a truncated pyramid. This six-bar linkage comprises six articulated struts, each coupled to two others by a revolute joint to form a closed loop. The six-bar linkage structure being convertible from a deployed state into a folded state and vice versa. In the deployed state, the six-bar linkage structure forming a trapezoid with two opposing first and second parallel sides, each of the first and second opposing parallel sides being formed by two struts arranged in series and coupled by a revolute joint at the center of the first and second parallel sides. In the folded state, the two struts of the first side being pivoted around the first revolute joint so that the opposing end portions of the two struts are located side by side and the two struts of the second side being pivoted around the second revolute joint so that the opposing end portions of the two struts are located side by side. The six-bar linkage structure constitutes the key element that allows constructing unit cells of scalable and modular deployable structures with double curvature. This deployable structure concept can be used for civil constructions, including but not limited to domes, roofs, housing, tents and bridges.

Claim <NUM> provides a deployable space reflector according to the present invention. Optional embodiments are defined by the dependent claims.

Advantages of this invention are in increasing deployed stiffness and stability, as well as in increasing reliability of deployment, achieving large deployed seized high accuracy of reflector realization and in decreasing height of the stowed package of the reflector.

A deployable space reflector comprises a deployable peripheral support framework <NUM>. The support framework <NUM> has two deployable peripheral polygonal rings <NUM> consisting of interconnected rods and connecting rods <NUM> of the rings <NUM> providing a certain separation of the rings <NUM>. The deployable space reflector has a tensioning framework <NUM> for shaping the reflecting surface, which comprises a front side network <NUM>, a back side network <NUM> and connecting ties <NUM>. A reflecting surface <NUM> is joined to the tensioning framework <NUM>. For increasing of stiffness, stability and deployment reliability of the deployable space reflector, one of the deployable peripheral polygonal rings <NUM> of the deployable support framework <NUM> of the reflector is made of hinged full cross-rods <NUM> and <NUM> placed in different planes. Cross-rods <NUM> and <NUM> are connected to the connecting rods <NUM> of the rings <NUM> with the rotation possibilities in the said planes and are provided with angular fittings <NUM> to enable rotation of the cross-rods <NUM> and <NUM> in the said planes, these fittings <NUM> may be made like fittings that known from patent <CIT>. One end of the rods <NUM> is connected to the end of one of the connecting rod <NUM> of the rings <NUM> with a fixed hinge <NUM> while the other end of the rods <NUM> is connected to the other connecting rod <NUM> of the rings <NUM> by joint <NUM> with a hinge and with the possibility of translation over its length. One end of the rod <NUM> of the other peripheral ring <NUM> is hinged fixed <NUM> to the other end of one of the connecting rods <NUM> of the rings <NUM> while the other end of the rod <NUM> is hinged <NUM> to the other connecting rod <NUM> of the rings <NUM> with the translation possibility along the connecting rod <NUM>. Support framework <NUM> in a conical configuration offers some more advantages like high stiffness and lower mass than cylindrically shaped. These can be emphasized by achieving the size of the opening angle of the ring rods <NUM> and <NUM> near zero degrees in deployed configuration (<FIG>).

According to the other alternative variant the both peripheral rings <NUM> of the peripheral support framework <NUM> consist of a single row of the rods <NUM>. The support framework <NUM> has connecting rods <NUM> of the rings which are inclined to the reflector axis forming trapeze-shaped bays <NUM> (<FIG>) of the so formed many-sided pyramidal support framework for increasing of its stiffness. For increasing reliability of deployment of the peripheral support framework <NUM> different length rods <NUM> of the trapeze-shaped bays <NUM> have synchronizers of deployment of the reflector, for example such as known from patent <CIT>, <FIG> and made as gear set.

The full cross-rods <NUM> and <NUM> of the peripheral support framework <NUM> are joining each other by a hinge <NUM> which provided which provides high stiffness, transfer of high torsional and bending moments between the rods <NUM> and <NUM>, and a gap-free rotation. The hinge <NUM> consist of parts, made for example as hoops <NUM>, which are fixing on the rods <NUM> and <NUM> and having stop blocks <NUM> on the inner sides of them. One stop block <NUM> has housing <NUM>, other stop block <NUM> - bearing <NUM> (<FIG>) for rotation in the housing and fixing device between the rods <NUM> and <NUM>, made for example as a bolt inside the hole (which are known from prior technical art and are not shown in the figures).

In a particular configuration, the cross full rods <NUM> and <NUM> of the peripheral support framework <NUM>, which are placed in different planes are not interconnected (<FIG>).

According to another embodiment of the deployable space reflector the peripheral support framework is inscribed in either cylindrical <NUM> or conical <NUM> shapes (<FIG> and <FIG>).

A deployment mechanism of the peripheral support framework <NUM> consists of rollers <NUM> which are installed on the ends of the rods <NUM> in the fixed <NUM>, and moving <NUM> joints (rollers <NUM> are not shown in joints <NUM>), and a cable <NUM> that is passing through the rollers <NUM> transmitted in one of bays of the peripheral support framework <NUM> along the ends of the rods <NUM>, and by analogy transmitted in each next bay. The cables <NUM> are provided with unwinding/winding drams <NUM> with drive units, which are mounted on an at least one connecting rod <NUM> of the rings <NUM> of the peripheral support framework <NUM>. The deployment mechanism further consists of rollers <NUM> which are mounted on the ends of the rods <NUM>, <NUM> in the fixed <NUM>, and moving <NUM> joints (rollers <NUM> are not shown in joints <NUM>), and a cable <NUM> that passes through the rollers <NUM> and is transmitted in each bays of the peripheral support framework <NUM> along the cross-rods <NUM>, <NUM>, for example firstly from a fixed joint <NUM> to the moving joint <NUM>, then along the rod <NUM> to the fixed joint <NUM>, then to the moving joint <NUM> and back to the fixed joint <NUM>, then along the rods <NUM> and by an analogy the cable <NUM> is transmitted in each next bays. The cables <NUM> are also provided by unwinding/winding drams <NUM> with drive units, which are setting on the at least one connecting rod <NUM> of the rings <NUM> of the peripheral support framework <NUM> (<FIG>). Latching mechanism is known from a previous art and can be performed as springed-teeth on the moving joints <NUM> and respective holes on the connecting rods <NUM> of the rings <NUM> of the support framework <NUM> of the reflector (not shown in drawings).

According to the next embodiment of the deployable space reflector for decreasing the stowed height, at least every second connecting rod <NUM> of the rings <NUM> of the peripheral support framework <NUM> is made with inner and outer parts <NUM> and <NUM> which have coupling bars <NUM>. The cross full rods <NUM> and <NUM> of the one ring <NUM> are connected to the inner part <NUM> of the connecting rods <NUM> of the rings <NUM>, while the ends of the rods <NUM> of the other polygonal ring <NUM> are connected to the outer <NUM> of the connecting rods <NUM> (<FIG>).

For compactness of the stowed package of the deployable space reflector, the rods <NUM>, <NUM> and <NUM> of the polygonal rings <NUM> which are hinged to the connecting rods <NUM> of the rings, either fixed <NUM> or with translation possibilities <NUM>, are joined pair-wise with rotation possibility around the axes of the connecting rods of the rings, with the limiting supports of the rotation angle <NUM> (<FIG>).

According to another main embodiment, a deployable space reflector comprising a peripheral support framework <NUM>, a tensioning framework <NUM> made of substantially inextensible front side and rear side networks <NUM>, <NUM>, which are interconnected with the substantially elastic links <NUM> and connected to the peripheral supporting framework <NUM>. The deployable reflector has a reflecting surface <NUM> connected to the tensioning framework <NUM>, a deployable mechanism and a latching mechanism which are made such as mechanisms of the first main variant of reflector. For reaching deployed reflector large sizes and decreasing the height of the stowed package, increasing of the stiffness and stability of the reflector, as well as decreasing the weight, simplifying and increasing reliability of deployment of the peripheral support framework <NUM>, the networks <NUM> and <NUM> of the tensioning framework <NUM> supporting the reflecting surface are made with the possibility of forming of a facetted shapes of double convex lens surfaces <NUM> around the axis of the reflector at least in the central part of it, with the formation possibility of facetted surfaces <NUM> of a double concave lens shape at the rest. Peripheral part of the reflector, with that, parts of the networks forming the facetted surfaces <NUM> of the double convex lens shape are connected to each other with at least one substantially elastic link <NUM>. Elastic links <NUM> made of a stable rod of a radio transparent material inside of the surfaces <NUM> of the double convex lens shape. The front network surface <NUM> part of the convex lens shape is made of the radio transparent material as well (<FIG>).

The tensioning framework <NUM> supporting the reflecting surface made with the possibility of forming of a facetted shapes of double convex lens surfaces <NUM> around the axis of the reflector may be connected to each other with one substantially elastic link <NUM> made of a stable rod.

The tensioning framework <NUM> supporting the reflecting surface made with the possibility of forming of facetted shapes of double convex lens surfaces <NUM> around the axis of the reflector may be connected to each other with many substantially elastic links <NUM> made of stable rods. The deployable space reflector facetted surfaces <NUM> of the double convex lens shape are formed via putting the front and rear sides of networks <NUM>, <NUM> through each other (<FIG> and <FIG>).

The tensioning framework <NUM> supporting the reflecting surface made with the possibility of forming of a facetted shapes of double convex lens surfaces <NUM> around the axis of the reflector may be used for the conical shapes peripheral support framework to make symmetrical and asymmetrical surfaces (<FIG> and <FIG>).

According additional embodiment of the deployable space reflector facetted surfaces <NUM> of the double convex lens shape are formed via bending of the networks <NUM> and <NUM> and bonding together at the places <NUM> of bending of the networks <NUM> and <NUM>, for example gluing and/or sewing of them (<FIG> and <FIG>).

The tensioning framework <NUM> of the deployable space reflector has front side stable rods of a radio transparent material, made for example, as substantially elastic links <NUM>. The tensioning framework <NUM> may be having circular, elliptical or other shaped supporting reflecting surface forming of facetted shapes of double convex lens surfaces <NUM>.

Claim 1:
A deployable space reflector comprising:
a peripheral support framework (<NUM>);
a tensioning framework (<NUM>) made of substantially inextensible front side and rear side networks (<NUM>, <NUM>) interconnected with substantially elastic links (<NUM>) and connected to the peripheral support framework (<NUM>);
a reflecting surface (<NUM>) connected to the tensioning framework (<NUM>);
a deployable mechanism; and
a latching mechanism;
characterized in that the front side and rear side networks (<NUM>, <NUM>) of the tensioning framework (<NUM>) support the reflecting surface and form facetted shapes that include:
double convex lens surfaces (<NUM>) around a central axis of the reflector at least in a central part of the reflector, wherein parts of the front side and rear side networks (<NUM>, <NUM>) forming the double convex lens surfaces (<NUM>) are connected to each other by at least one of the substantially elastic links (<NUM>) that is made of a stable rod of a radio transparent material, and wherein the part of the convex lens surface (<NUM>) that corresponds to the front side network (<NUM>) is made of the radio transparent material; and
a double concave lens shape (<NUM>) about the periphery of the double convex lens surfaces (<NUM>).