JP2006229750A - Unfolding antenna for space - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an expansion type antenna for space which can eliminate the need of designing a tension structure, mesh unfolding resistance, entanglement prevention and the like and simplify the assembling and adjustment of antenna mirror finished surfaces. <P>SOLUTION: Thin film segments 6 are shaped in a truncated sector obtained by radially dividing the plane shape of a paraboloid of revolution and have a out-of-plane stiffness. Two thin film segments 6 are arranged between each pair of rear face ribs 4 adjacent in a circumferential direction, truncated sector-shaped side faces of two thin film segments 6 are connected to each other at a plurality of places in a radial direction, and the other truncated sector-shaped side face of each thin film segment 6 is connected to the rear face rib 4 at a plurality of places in a radial direction to constitute an antenna reflecting mirror 2. The antenna reflecting mirror 2 is folded in the shape of a mountain at a position corresponding to the rear face ribs 4 and folded in the shape of valley at the mutually confronting parts of the truncated sector-shaped side faces of two thin film segments 6 between a pair of rear face ribs 4 adjacent in a circumferential direction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a deployable antenna mounted on space equipment such as an artificial satellite, and more particularly to a structure of an antenna reflector that can be reliably and easily deployed when deployed in space.

  A conventional deployable antenna for space is developed from a metal mesh that constitutes a radio wave reflecting surface of the antenna, a cable that retains its shape, a metal mesh and a cable folded, and after deployment, a metal mesh and a cable network. A deployable antenna having a deployable rib, a deployable hinge that retains the deployable rib, and a center hub that fixes the deployable hinge, and a storage cable having one end for retaining the cable attached to the cable; It is provided on the center hub, and when the antenna reflector is housed, the other end of the housing cable is discretely fixed to the center hub. To maintain the addition of the antenna reflector, a force in the unfolding direction is applied to the housing cable along with the addition of the addition slot. A storage cable release mechanism that sequentially opens the other end of the storage cable from the center hub. (E.g., see Patent Document 1).

Japanese Patent Laid-Open No. 7-226620

The conventional space deployable antenna has the following problems because the antenna mirror surface (radio wave reflecting mirror) is formed of a metal mesh having no rigidity.
First, it is necessary to design the tension structure and the mesh deployment resistance so that the antenna mirror surface can be developed so as to obtain high surface accuracy.
Secondly, in order to solve the problem that the metal mesh and the cable become untangled during deployment, the storage cable is discretely attached to the cable, and the storage cable is released by the storage cable release mechanism. Sometimes an extremely complex entanglement prevention mechanism is required that opens sequentially.
Thirdly, much time and cost are required for assembling and adjusting the antenna mirror surface.

  The present invention has been made in order to solve the above problems, and has a plurality of thin films each having an out-of-plane rigidity for maintaining a surface shape obtained by radially dividing a paraboloid of revolution and functioning as a radio wave reflecting surface. The purpose is to obtain a deployable antenna for space that can configure the antenna mirror surface with segments and eliminate the need for design such as tension structure, mesh deployment resistance and entanglement prevention, and easy assembly and adjustment of the antenna mirror surface. To do.

  The space deployable antenna according to the present invention has a disk-shaped center hub, and one end of each of which is rotatably attached to the center hub and arranged at a predetermined pitch in the circumferential direction of the center hub. A plurality of back ribs that take a storage position that surrounds the tube in a cylindrical shape and a deployment position that is opened radially from the center hub; An antenna reflector that is supported by the multiple back ribs so as to expand and constitutes a radio wave reflecting surface having a surface shape of a paraboloid of rotation in the expanded state. The antenna reflector is formed into a truncated fan shape obtained by radially dividing the surface shape of the rotating paraboloid, and is restored to the surface shape of the rotating paraboloid in an unloaded state. A plurality of thin film segments having rigidity, each of which is disposed between the pair of back ribs adjacent to each other in the circumferential direction; And the other side edges of the two thin film segments are connected to each other at a plurality of locations in the radial direction so as to be rotatable about a rotation axis along the opposing portion of the side edges. A plurality of radial positions are connected to the back rib so as to be rotatable about a rotation axis along the other side. Further, the antenna reflecting mirror is mountain-folded at a position corresponding to the back rib, and is opposed to the fringe-shaped side edges of the two thin film segments between a pair of the back ribs adjacent in the circumferential direction. It is folded and stored in a valley fold.

  According to the present invention, the antenna reflector is formed into a truncated fan shape obtained by radially dividing the surface shape of the rotating paraboloid, and is restored to the surface shape of the rotating paraboloid in an unloaded state. A large number of thin-film segments having out-of-plane rigidity are configured by connecting truncated fan-shaped sides. Therefore, when the back ribs are deployed radially, each thin film segment restores itself to the paraboloidal surface shape due to its out-of-plane rigidity, so the tension structure required when configuring the antenna mirror surface with a metal mesh In addition, it is not necessary to design the mesh deployment resistance. Furthermore, a cable and a cable release mechanism that are necessary when the antenna mirror surface is formed of a metal mesh are not required. Thereby, the assembly and adjustment of the antenna mirror surface can be simplified and the cost can be reduced.

Embodiment 1 FIG.
FIG. 1 is a perspective view schematically showing a storage state of a space deployable antenna according to Embodiment 1 of the present invention, and FIG. 2 is a schematic view of a space deployable antenna according to Embodiment 1 of the present invention. FIG. 3 is a perspective view schematically showing a deployment transient state of the space deployable antenna according to the first embodiment of the present invention, and FIG. 4 is a diagram according to the first embodiment of the present invention. FIG. 5 is a perspective view schematically showing the deployment completion state of the space deployment antenna according to Embodiment 1 of the present invention, and FIG. 6 is a perspective view schematically showing the deployment completion state of the space deployment antenna. FIG. 7 is a main part enlarged perspective view schematically showing a deployment completion state of the space deployable antenna according to the first embodiment of the invention, and FIG. 7 shows the antenna reflector of the space deployable antenna according to the first embodiment of the present invention. Fiber reinforced plastic that is the material of the thin film segment Plan view illustrating the orientation direction of the reinforcing fibers in tick, Fig. 8 is a perspective view showing the configuration of the connecting member to be applied to space for deployment type antenna according to the first embodiment of the present invention. In addition, in FIG. 1, FIG. 3 thru | or FIG. 5, the connection member is abbreviate | omitted.

  1 to 6, the deployable antenna 1 includes an antenna reflector 2 having a radio wave reflecting surface that forms a surface shape of a rotating paraboloid in a deployed state, a disk shape, and the center position of the antenna reflector 2. A center hub 3 disposed on the antenna reflector, a plurality of back ribs 4 that support the back surface of the antenna reflector 2, and a deployment mechanism 5 that houses and deploys the plurality of back ribs 4 in an umbrella shape. .

  The back rib 4 is formed into a T-shaped cross section using, for example, titanium, stainless steel, etc., and the end surface of the T-shaped standing side 4a faces the antenna reflecting mirror 2 side, and the center hub 3 is the center. They are arranged radially at an angular pitch, and one end of each is rotatably connected to the outer peripheral portion of the center hub 3 via a developing hinge (not shown). And the end surface of the T-shaped upright side 4a of the back rib 4 is formed in a curved surface shape equivalent to the surface shape in the radial direction of the paraboloid of revolution that constitutes the radio wave reflecting surface of the antenna reflector 2 in the unfolded state. Yes.

  The antenna reflecting mirror 2 has a large number of thin film segments 6 formed in a truncated fan shape obtained by radially dividing a paraboloid of revolution. Each thin film segment 6 is formed by dividing the rotational paraboloid radially by using CFRP (Carbon Fiber Reinforced Plastic), for example, which is made of polyether ether ketone resin or polyether sulfone resin as a matrix and reinforced with carbon fiber. The film is formed into a fan-shaped thin film, and the surface of the thin film is covered with a conductive material such as carbon, aluminum, or copper. Two thin film segments 6 are disposed between each pair of adjacent back ribs 4 arranged radially. In each pair of the two thin film segments 6, the end surfaces of the truncated fan-shaped sides are brought close to each other, the back surfaces of the thin film segments 6 are connected by the connecting member 7, and The back surface of the thin film segment 6 and the side surface of the standing side 4 a of the back rib 4 are connected by the connecting member 7 with the end surface of the side edge being brought close to the end surface of the T-shaped upstanding side 4 a of the back rib 4. Further, the connecting members 7 are arranged at a predetermined pitch in the radial direction.

Here, the thin film segment 6 is formed into a surface shape of a paraboloid of revolution by, for example, autoclave molding, and has out-of-plane rigidity. That is, the thin film segment 6 is shaped to be elastically deformed while changing its surface shape in a loaded state, and to be restored to the surface shape of the paraboloid when the load is released.
Further, as shown in FIG. 7, the carbon fiber 8 that is a CFRP reinforcing fiber for forming the thin film segment 6 is knitted so as to have three fiber orientation directions with an intersection angle of 60 °. CFRP reinforced with this triaxial type carbon fiber exhibits strength according to the strength of the fiber in the fiber direction, but the anisotropy that the strength becomes very weak in the direction perpendicular to the fiber direction is eliminated. The same rigidity and elastic modulus can be obtained in any direction. By using this CFRP, the thermal expansion coefficient of the thin film segment 6 can be adjusted to zero.

The connecting member 7 is made of CFRP, which is the material of the thin film segment 6, in a rectangular flat plate shape, and only the region of the dividing line 7a that divides the longitudinal direction into two is in an unimpregnated state of the matrix. That is, as shown in FIG. 8, the connecting member 7 is formed by connecting a pair of joint portions 7b formed of a CFRP into a rectangular flat plate shape by a dividing line 7a with a predetermined gap. Since the dividing line 7a is composed of only carbon fibers, the connecting member 7 can be bent at the portion of the dividing line 7a.
The connecting member 7 is bonded and fixed to the back surface of the adjacent thin film segment 6 with the dividing line 7a along the opposing portion of the end faces of the truncated fan-shaped side edges of the thin film segment 6. . As a result, the two thin film segments 6 are connected so as to be rotatable, that is, bendable, with the dividing line 7a of the connecting member 7 as a rotation axis. In addition, the connecting member 7 is formed by joining the dividing line 7a along the facing portion between the end face of the other side of the truncated fan shape of the thin film segment 6 and the end face of the T-shaped upright side 4a of the back rib 4. The part 7 b is bonded and fixed to the back surface of the thin film segment 6 and the side surface of the T-shaped upstanding side 4 a of the back rib 4. Thereby, each thin film segment 6 is connected to the back rib 4 so as to be rotatable, that is, bendable, with the dividing line 7a of the connecting member 7 as a rotation axis.

Next, the retracted state of the deployable antenna 1 configured as described above will be described.
The two thin film segments 6 disposed between the adjacent back ribs 4 are connected so that the truncated fan-shaped sides of the thin film segment 6 can be bent with the dividing line 7a of the connecting member 7 as a rotation axis. Further, the other side edges of the thin film segment 6 in a truncated fan shape are connected to the standing side 4a of the back rib 4 so as to be bendable with the dividing line 7a of the connecting member 7 as a rotation axis.
Therefore, in the retracted state of the deployable antenna 1, as shown in FIG. 1, the back ribs 4 are moved to the retracted positions substantially parallel to the center of the center hub 3 by the unfolding mechanism 5. Are arranged in a substantially cylindrical shape. The two thin film segments 6 disposed between the adjacent back ribs 4 are valley folds in which the connecting portions of the truncated fan-shaped sides of the thin film segment 6 are close to the axial center position of the center hub 3 (see FIG. The connecting portion between the truncated fan-shaped sides is bent in a valley state when viewed from the back side. As a result, as shown in FIG. 2, the antenna reflecting mirror 2 is housed by being folded in a mountain fold at each back rib 4 and in a valley fold between adjacent back ribs 4. At this time, the surface shape of each thin film segment 6 is elastically deformed against the out-of-plane rigidity. That is, each thin film segment 6 is accumulated with a restoring force for returning to the surface shape of the paraboloid of revolution.
Thus, the deployable antenna 1 is mounted on a rocket with the antenna reflector 2 folded and stored alternately in a valley fold and a mountain fold.

Next, a deployment operation of the deployable antenna 1 in space will be described.
Each back rib 4 is expanded by the expanding mechanism 5 so that the angle formed with the axis of the center hub 3 is gradually increased. At this time, as shown in FIG. 3, the angle formed between the adjacent back ribs 4 gradually increases, whereby the angle formed between the two thin film segments 6 located between the adjacent back ribs 4 gradually increases. growing. Then, as shown in FIGS. 4 to 6, when the development of each back rib 4 is completely completed, the angle formed by the two adjacent thin film segments 6 becomes approximately 180 °, and the surface shape of the paraboloid of revolution. Thus, the antenna reflector 2 having the radio wave reflecting surface developed in FIG.

This type of deployable antenna has a maximum length (the aperture diameter of the radio wave reflecting surface becomes the maximum length in the deployed state) due to the rocket mountability. However, in the deployable antenna 1 according to the first embodiment, the antenna reflecting mirror 2 is alternately folded and stored in a valley fold and a mountain fold, so that the maximum length when stored is: The length of the deployable antenna 1 in the axial direction is reduced to about ½ of the aperture diameter of the antenna reflector 2, and a deployable antenna having an aperture diameter of 8 to 10 m can be mounted on the rocket.
Further, since the thin film segments 6 have out-of-plane rigidity, in the deployment transition state of the back rib 4, each thin film segment 6 is released from the accumulated restoring force, and the surface shape of the paraboloid of revolution itself. Deforms to return to. Further, when the development of the back rib 4 is completed, no load is applied to each thin film segment 6, and each thin film segment 6 is completely restored to the surface shape of the rotating paraboloid. Therefore, it is not necessary to design the tension structure and the mesh deployment resistance in the conventional deployable antenna in which the antenna mirror surface is configured by a mesh. Further, a very complicated metal mesh and a cable entanglement preventing mechanism in the conventional deployable antenna are not required. Furthermore, the assembly and adjustment of the antenna reflector 2 can be simplified, and the manufacturing time and cost of the antenna can be greatly reduced as compared with the conventional deployable antenna.

Further, since the thin film segment 6 is made of CFRP, the weight can be significantly reduced as compared with a conventional deployable antenna using a metal mesh.
Moreover, since CFRP is reinforced with the triaxial type carbon fiber fabric, the coefficient of thermal expansion of the thin film segment 6 can be adjusted to zero, and the surface accuracy of the radio wave reflecting surface of the antenna reflector 2 can be improved.

The connecting member 7 is formed of CFRP in a rectangular flat plate shape, and only the region of the dividing line 7a that divides the longitudinal direction into two is in an unimpregnated state of the matrix, and can be bent at the portion of the dividing line 7a. ing. Since the connecting member 7 is deformed to realize the storing and unfolding operation of the antenna reflecting mirror 2, there is no backlash in the rotating portion at the hinge having the mechanical rotating portion, and the unfolded radio wave reflection. The surface accuracy of the surface is increased. That is, when a hinge having a mechanical rotating part is applied as a connecting member, there has been a problem that the surface accuracy of the radio wave reflecting surface due to backlash in the rotating part of the hinge is lowered when the antenna reflector is deployed. By using this connecting member 7, a decrease in surface accuracy of the radio wave reflecting surface is suppressed.
Furthermore, since the connecting member 7 is deformed, the connecting member 7 is easily adapted to the thin film segment 6 having a curvature, and an increase in the development resistance due to the use of the connecting member 7 is suppressed.

In the first embodiment, a thermoplastic resin such as a polyether ether ketone resin or a polyether sulfone resin is used as the CFRP matrix for producing the thin film segment 6, but the matrix is an epoxy resin or an unsaturated polyester. A thermosetting resin such as a resin may be used.
In the first embodiment, the thin film segment 6 is made of CFRP reinforced with triaxial carbon fibers. However, the biaxial carbon knitted so as to have two fiber orientation directions orthogonal to each other. A thin film segment may be produced by laminating CFRP films reinforced with fibers so that the fiber orientation directions are orthogonal to each other. Also in this case, the anisotropy is eliminated and the same rigidity and elastic modulus can be obtained in any direction as in the case of CFRP reinforced with the triaxial carbon fiber.
In the first embodiment, the thin film segment 6 is made of CFRP. However, the material of the thin film segment 6 is not limited to CFRP, as long as it has an out-of-plane rigidity. For example, fiber reinforced plastics such as AFRP (Aramid Fiber Reinforced Plastic) reinforced with aramid resin and HFRP (Hybrid Fiber Reinforced Plastic) reinforced with hybrid fibers such as carbon fiber and aramid fiber may be used.

In the first embodiment, the description will be made on the assumption that the CFRP is formed in a rectangular flat plate shape, and the connecting member 7 is used in which only the region of the dividing line 7a that divides the longitudinal direction into two is in an unimpregnated state of the matrix. However, the connecting member is not limited as long as it can be deformed (bent) to accommodate and deploy the antenna reflector 2. For example, AFRP having a large breaking strain formed into a thin plate, an aromatic polyimide film, etc. A plastic film, a metal mesh braided with a molybdenum wire plated with gold, a C spring made of CFRP, or the like can be used. Here, if an aromatic polyimide film is used as the connecting member, the deployment durability of the antenna reflector 2 is improved. Further, if a C spring is used as the connecting member, the rigidity of the entire radio wave reflecting surface of the antenna reflecting mirror 2 is improved.
In the first embodiment, the back rib 4 is made of a metal material such as titanium or stainless steel. However, the back rib is formed by laminating and integrating a large number of thin CFRP prepregs. May be. In this case, the deployable antenna can be reduced in weight.

Embodiment 2. FIG.
FIG. 9 is a perspective view schematically showing a main part of a storage state of the space deployable antenna according to the second embodiment of the present invention.
In FIG. 9, the deployable antenna 1 </ b> A is housed by being wound spirally after the two thin film segments 6 between the back ribs 4 are folded into valley folds.
Other configurations are the same as those in the first embodiment.

  In this deployable antenna 1A, the two thin film segments 6 between the back ribs 4 are each folded into a valley fold and further wound in a spiral shape. The size can be reduced, and the mountability to the rocket is further improved.

Embodiment 3 FIG.
10 is an enlarged perspective view of a main part schematically showing a storage state of the space deployable antenna according to the third embodiment of the present invention, and FIG. 11 is a deployment of the space deployable antenna according to the third embodiment of the present invention. It is a principal part expansion perspective view which shows a completion state typically.
10 and 11, the thin film segment 6A is a substantially triangular sub-segment divided by a line segment connecting a substantially central portion in the length direction of the side of the truncated sector and a substantially central portion in the circumferential direction of the outer periphery. 6b and the remaining main segment 6a. Then, the thin film segment 6A is formed by connecting both joints 7b of the connecting member 7 with the division lines 7a along the opposing portions of the division end faces, with the division end faces of the main segment 6a and the sub-segment 6b close to each other. And the sub-segment 6b are bonded to the back surface to form a truncated sector as a whole. Similar to the thin film segment 6, the thin film segment 6 </ b> A is formed in a truncated fan shape in which the paraboloid of revolution is radially divided and has out-of-plane rigidity.
The two thin film segments 6A are disposed between the back ribs 4 so as to face the sub-segment 6b, and the second thin film segments 6A are connected to each other along the dividing line 7a at the opposed portions of the end faces of the truncated fan-shaped sides. The 1st and 2nd junction part 7b is adhere | attached and connected with the back surface of 6 A of adjacent thin film segments. At this time, the sub-segments 6b of the two thin film segments 6A are connected to each other by the connecting member 7.
Other configurations are the same as those in the first embodiment.

As shown in FIG. 10, the deployable antenna 1B configured as described above includes two thin film segments 6A between adjacent back ribs 4, a connecting portion between the main segments 6a, a main segment 6a, and a sub-segment 6b. And are folded and stored in a mountain fold at the connecting portion between the sub-segments 6b.
Further, when the deployable antenna 1B deploys the back ribs 4, both the main segments 6a connected to the back ribs 4 rotate with respect to the back rib 4 using the dividing line 7a of the connecting member 7 as a rotation axis. It is developed so that the angle formed by both main segments 6a is approximately 180 °. Further, the two main segments 6a disposed between the adjacent back ribs 4 rotate about the dividing line 7a of the connecting member 7 connecting the two main segments 6a as the rotation axis, and the two main segments 6a It is developed so that the angle formed is approximately 180 °. Further, the adjacent main segment 6a and sub-segment 6b rotate about the dividing line 7a of the connecting member 7 connecting the main segment 6a and the sub-segment 6b as a rotation axis, and the main segment 6a and the sub-segment 6b It is developed so that the angle formed is approximately 180 °. Further, the adjacent sub-segments 6b rotate about the dividing line 7a of the connecting member 7 connecting the sub-segments 6b as a rotation axis so that the angle formed by both the sub-segments 6b is approximately 180 °. Be expanded. And each main segment 6a and subsegment 6b are each restored | restored in the surface shape of a rotation paraboloid by the out-of-plane rigidity. Thereby, the antenna reflecting mirror 2A having the radio wave reflecting surface developed in the surface shape of the rotating paraboloid is constructed.

  As described above, according to the third embodiment, the antenna reflector 2A is alternately and evenly folded into the valley fold and the mountain fold, and further, the outer peripheral portion of the valley fold is folded back into the mountain fold. Since it is housed, the outer periphery of the truncated fan shape of the thin film segment 6A having a long circumferential length is folded back into two substantially. Therefore, when the deployable antenna 1B is in the retracted state, the amount of extension of the thin film segment 6A from the tip of the back rib 4 in the axial direction of the center hub 3 is halved, and the radial outer dimension in the retracted state is reduced. , Mounting on rockets is further improved.

Embodiment 4 FIG.
In the fourth embodiment, a long metal mesh produced by braiding gold-plated molybdenum fine wires opens a gap between the truncated fan-shaped side edges of adjacent thin film segments 6 to the truncated fan-shaped side. It is bonded to the surface side of the adjacent thin film segment 6 so as to cover the entire length of the side.
Other configurations are the same as those in the first embodiment.

  According to the fourth embodiment, since the gap between the thin film segments 6 is closed with the metal mesh, it is possible to construct an antenna reflector that uses the entire paraboloid of revolution as the radio wave reflecting surface.

It is a perspective view which shows typically the accommodation state of the space | gear deployment type antenna which concerns on Embodiment 1 of this invention. It is a principal part expansion perspective view which shows typically the accommodation state of the space | gear deployment type antenna which concerns on Embodiment 1 of this invention. It is a perspective view which shows typically the expansion | deployment transition state of the expansion | deployment type | formula antenna for space concerning Embodiment 1 of this invention. It is a side view which shows typically the completion state of expansion | deployment of the space | gear deployment type antenna which concerns on Embodiment 1 of this invention. It is a perspective view which shows typically the deployment completion state of the space | gear deployment type antenna which concerns on Embodiment 1 of this invention. It is a principal part expansion perspective view which shows typically the completion state of expansion | deployment of the space | gear deployment type antenna which concerns on Embodiment 1 of this invention. It is a top view explaining the orientation direction of the reinforced fiber in the fiber reinforced plastic which is the material of the thin film segment which comprises the antenna reflector of the space | gear deployment type antenna which concerns on Embodiment 1 of this invention. It is a perspective view which shows the structure of the connection member applied to the space | gear deployment type antenna which concerns on Embodiment 1 of this invention. It is a principal part perspective view which shows typically the accommodation state of the space | gear deployment type antenna which concerns on Embodiment 2 of this invention. It is a principal part expansion perspective view which shows typically the accommodation state of the space | gear deployment type antenna which concerns on Embodiment 3 of this invention. It is a principal part expansion perspective view which shows typically the completion state of expansion | deployment of the space | gear deployment type antenna which concerns on Embodiment 3 of this invention.

Explanation of symbols

  1,1A, 1B Deployable antenna, 2,2A antenna reflector, 3 center hub, 4 back rib, 6,6A thin film segment, 6a main segment, 6b subsegment, 7 connecting member, 7a dividing line, 7b joint ( First and second joints), 8 carbon fibers.

Claims (8)

A disc-shaped center hub,
One end of each center hub is rotatably attached to the center hub and arranged at a predetermined pitch in the circumferential direction of the center hub. The storage position surrounds the center of the center hub in a cylindrical shape, and is opened radially from the center hub. A large number of back ribs that take the open position,
A radio wave reflecting surface that is supported by the plurality of back ribs so as to be housed and deployed in conjunction with the rotational movement of the plurality of back ribs with respect to the center hub, and has a paraboloidal surface shape in the deployed state. Comprising an antenna reflector to constitute,
The antenna reflector is formed into a truncated fan shape obtained by radially dividing the surface shape of the rotating paraboloid, and has an out-of-plane rigidity that restores the surface shape of the rotating paraboloid in an unloaded state. A plurality of thin film segments, and two thin film segments are disposed between the pair of circumferentially adjacent back ribs, and the two thin film segments face each other in the shape of a truncated fan. Let the other side edges of the two thin film segments be connected in a radial direction so as to be pivotally connected around a rotation axis along the opposing portions of the side edges at a plurality of radial positions. Are configured to be pivotally connected to the back rib at a plurality of locations around a rotation axis along the other side,
The antenna reflector is mountain-folded at a position corresponding to the back rib, and at a facing portion between the truncated fan-shaped sides of the two thin film segments between a pair of the back ribs adjacent in the circumferential direction. An expandable antenna for space use, which is folded and stored in a valley fold.   The thin film segment is formed by forming CFRP into a truncated fan shape obtained by radially dividing the surface shape of the paraboloid of revolution, and covering the surface with a conductive material. 1. A deployable antenna for space according to 1.   3. The space deployable antenna according to claim 2, wherein the carbon fiber of the CFRP is knitted so as to have three fiber orientation directions having an intersecting angle of 60 ° with each other.   2. The deployable antenna for space according to claim 1, wherein the thin film segments and the thin film segments and the back rib are connected by a connecting member that is bent to form the rotating shaft.   The connecting member is formed by connecting the first and second joint portions formed of a plastic whose matrix is reinforced with fibers into a flat plate shape with a predetermined gap, and the first and second joints. The joint portion is joined to the thin film segment or the back rib, and the fiber portion located between the first and second joint portions constitutes the rotating shaft. Deployable antenna for space.   5. The space deployable antenna according to claim 4, wherein the connecting member comprises a C spring.   The antenna reflector in the stowed state has a spirally folded portion folded in a valley fold at the opposed portions of the two fan-shaped side portions of the thin film segments between the pair of back ribs adjacent in the circumferential direction. 2. The deployable antenna for space according to claim 1, wherein the antenna is wound. The thin film segment is divided into a substantially triangular sub-segment including a predetermined region on the outer periphery, a predetermined region on the side, and a remaining main segment from the intersection of the fringe-shaped outer periphery and the side. And the main segment are configured such that the divided surfaces face each other and are pivotally connected around a rotation axis along a facing portion of the divided surfaces at a plurality of locations.
The two thin film segments disposed between the pair of adjacent back ribs are arranged so that the sub-segments are opposed to each other, and the sub-segments and the main segments are opposed to each other in a plurality of radial directions. It is connected so that it can freely rotate around the rotation axis along the facing part.
The antenna reflector in the stored state is valley-folded at the opposed portions of the main segments of the two thin film segments between the pair of back ribs adjacent in the circumferential direction, and at the opposed portions of the sub-segments. 2. The space deployable antenna according to claim 1, wherein the space-foldable antenna is folded in a mountain fold and further in a valley fold at an opposing portion of the main segment and the sub-segment of each thin film segment.

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