FR3060536A1 - SPACE ENGINE - Google Patents

Abstract

The invention relates to a spacecraft (2) comprising a body (4) having a face (16, 18), a radiator (22, 23) carried by said face, and a thermal insulation device (28) carried by the radiator. The thermal insulation device comprises: - a first screen device (30) able to cover a first zone (32) of said radiator, said first screen device (30) comprising a thermally insulating and flexible sheet, and at least two springs adapted to producing a constant reaction force, said springs being preformed so as to wind on themselves at rest and being fixed on the insulating sheet, said springs each having an end fixed on the radiator a free end; and a pulling device (34) capable of pulling on the free end of said springs so that the sheet covers the first zone and to release the free end to expose the first zone towards the space.

Description

060,536

62687 ® FRENCH REPUBLIC

NATIONAL INSTITUTE OF INDUSTRIAL PROPERTY © Publication number:

(to be used only for reproduction orders)

©) National registration number

COURBEVOIE © Int Cl ⁸ : B 64 G 1/50 (2017.01)

PATENT INVENTION APPLICATION

A1

©) Date of filing: 16.12.16. © Applicant (s): AIRBUS DEFENSE AND SPACE SAS (© Priority: Simplified joint stock company - FR. @ Inventor (s): DELTOUR BERNARD and LECONTE SYLVAIN. (43) Date of public availability of the request: 22.06.18 Bulletin 18/25. ©) List of documents cited in the report preliminary research: Refer to end of present booklet (© References to other national documents ® Holder (s): AIRBUS DEFENSE AND SPACE SAS related: Joint stock company. ©) Extension request (s): © Agent (s): CABINET PLASSERAUD.

(M) SPACE ENGINE.

FR 3 060 536 - A1 _ The invention relates to a spacecraft (2) comprising a body (4) having a face (16, 18), a radiator (22, 23) carried by said face, and an isolation device thermal (28) carried by the radiator. The thermal insulation device includes:

- A first screen device (30) capable of covering a first zone (32) of said radiator, said first screen device (30) comprising a thermally insulating and flexible sheet, and at least two springs capable of producing a constant reaction force, said springs being preformed so as to roll up on themselves at rest and being fixed on the insulating sheet, said springs each having one end fixed on the radiator with a free end; and

- A traction device (34) capable of pulling on the free end of said springs so that the sheet covers the first zone and of releasing the free end to expose the first zone towards space.

Spacecraft

The present invention is in the field of spacecraft.

In particular, the present invention relates to the field of thermal control of telecommunications satellites.

The heat dissipation of the payload of telecommunication satellites is ensured by radiators mounted on the North and South walls. These radiators are dimensioned so as to allow the heat generated by the payload to be removed under extreme operating conditions, typically when the payload is operating at full speed, the reflective surface of the radiators is degraded and assuming that one is during the Solstice period and consequently one of the radiators is heated by incident solar radiation.

In opposite extreme operating conditions such as when transferring the satellite from the injection orbit to the geostationary orbit, the payload will be subjected to very cold temperatures. It will then be reheated, for example by heaters, to keep it above its minimum operating temperature. The electric power necessary for this heating can represent up to 30% of the electric power generated by solar generators. It would be desirable to use this electrical power for other purposes, for example to increase the propelling force of the satellite during the transfer phase and thus shorten the duration of the transfer. This is all the more critical when using electric propulsion (alone or alternating with chemical propulsion) because the transfer times last several months.

The document FR 2 823 182 proposes to equip the satellites with deployable radiators having a radiant face and an insulating face. During the satellite transfer phase to the geostationary orbit, the deployable radiators are folded so that their insulating face is directed towards space. Once in geostationary orbit, these deployable radiators are deployed so that their radiant surface is directed towards space.

However, these deployable radiators are expensive, bulky and complex to install, in particular because of the difficulty in producing and mounting heat transfer systems from the radiators to the deployable radiators.

Furthermore, in the deployed position, these deployable radiators protrude laterally or vertically from the body of the satellite so that their deployment and folding cannot be controlled in a manner decolerated from the position or movement of the other appendages of the satellite. Thus, the deployed position of the deployable radiator is not compatible with all the positions of the solar panels, with all the positions of the antennas or with the use of certain thrusters.

The present invention aims to provide a spacecraft comprising a space-saving thermal insulation device, light and capable of being implemented independently of the positions of the other appendages.

To this end, the subject of the invention is a spacecraft comprising a body having at least one face, at least one radiator carried by said face, and at least one thermal insulation device carried by the radiator, characterized in that said thermal insulation device includes:

- A first screen device capable of covering a first zone of said radiator, said first screen device comprising a thermally insulating and flexible sheet, and at least two springs capable of producing a constant reaction force, said springs being preformed so as to roll up on themselves at rest, said springs being fixed on the insulating sheet, said springs each having a first end fixed to a traction device and a second end fixed to the radiator; and

a traction device suitable for pulling in a direction of traction on the first end of said springs of the first screen device so that the insulating sheet covers the first zone in a mode known as deployed mode, said traction device being able to release the first end said springs for exposing the first zone to space in a mode called exposure mode.

According to particular embodiments, the spacecraft includes one or more of the following characteristics:

- The first screen device comprises at least two cables, each cable being integral with said traction device and the first end of the springs, said cables being interposed between two windings of the springs in the exposure mode;

- The first screen device further comprises a support rod extending in a direction perpendicular to the direction of traction and at least two first stops fixed on the radiator between the insulating sheet and the traction device, said first stops being suitable for wedge the support rod during the launch of the spacecraft;

- the traction device comprises:

- a traction shaft rotatably mounted about an axis of rotation, said traction shaft extending perpendicular to the direction of traction, the first end of said springs being integral with said traction shaft; and

- a device for locking the rotation of the traction shaft around said axis of rotation;

- The traction device comprises an actuator capable of driving the traction shaft in rotation;

- The traction device further comprises a damping device capable of damping the rotation of the traction shaft, when the locking device is unlocked;

- The thermal insulation device further comprises a second screen device capable of covering a second area, said second screen device being identical to the first screen device, the springs of said second screen device extending parallel to the direction of traction;

- The first screen device and the second screen device are arranged on the same side of the traction device, and in which, in the exposure mode, the springs of the first screen device and the springs of the second screen device are wound on themselves in the same winding direction.

the insulating sheet of the second screen device is arranged in the extension of the insulating sheet of the first screen device in the direction of traction;

- The insulating sheet of the second screen device is arranged in the extension of the insulating sheet of the first screen device in a direction perpendicular to the direction of traction;

- The traction device is arranged between the first screen device and the second screen device and in which, in the exposure mode, the springs of the first screen device are wound on themselves in a first winding direction and the springs of the second screen device wind on themselves in a second winding direction, the second winding direction being opposite to the first winding direction;

the insulating sheet of the first screen device has a length greater than the length of the insulating sheet of the second screen device, said length being measured according to the direction of traction, and in which the traction shaft supports at least two pulleys of diameter greater than diameter of the traction shaft, said cables of the second screen device wound on said pulleys.

- The insulating sheet of the first screen device has a width greater than the width of the second screen device, said width being measured in a direction perpendicular to the direction of traction;

- The first screen device comprises at least two ramps fixed to the radiator in a direction parallel to the direction of traction, at least one of the springs and the ends of the support rods being adapted to bear against said ramps in the mode deployed, said ramps having ramp portions which project from the radiator;

- At least one edge of the insulating sheet has at least one cut;

- The spacecraft comprises a first gear mechanism fixed to the free end of a traction shaft, an angle transmission device coupled to the first gear mechanism, an additional traction shaft having a second mechanism 'gear coupled to the angle transmission device and at least one additional screen device fixed by cables to the additional traction shaft; the additional traction shaft extending in the direction of traction;

- Said springs are flat strips of stainless steel in the form of a ribbon, said strips having a width of between 5 and 30 millimeters;

- the insulating sheet is a Kapton sheet covered with a layer of aluminum.

The invention will be better understood on reading the description which follows, given solely by way of example and made with reference to the figures in which:

FIG. 1 is a schematic perspective view of a spacecraft according to the present invention,

- Figure 2 is a perspective view of a thermal insulation device according to a first embodiment, said thermal insulation device being adapted to be supported by the spacecraft illustrated in Figure 1;

- Figure 3 is a perspective view of a spring of the thermal insulation device illustrated in Figure 1;

- Figure 4 is a sectional diagram of the thermal insulation device illustrated in Figure 3, showing the operating principle of the thermal insulation device during the exposure mode;

- Figure 5 is a sectional diagram of the thermal insulation device illustrated in Figure 3, showing the operating principle of the thermal insulation device during deployment mode;

- Figure 6 is a perspective view of a thermal insulation device according to a second embodiment, said thermal insulation device being adapted to be supported by the spacecraft illustrated in Figure 1;

- Figure 7 is a perspective view of a thermal insulation device according to a third embodiment, said thermal insulation device being adapted to be supported by the spacecraft illustrated in Figure 1;

- Figure 8 is a perspective view of a thermal insulation device according to a fourth embodiment, said thermal insulation device being adapted to be supported by the spacecraft illustrated in Figure 1;

- Figure 9 is a perspective view of a thermal insulation device according to a fifth embodiment, said thermal insulation device being adapted to be supported by the spacecraft illustrated in Figure 1;

- Figure 10 is a sectional diagram of the thermal insulation device illustrated in Figure 9, showing the operating principle of the thermal insulation device during the exposure mode;

- Figure 11 is a sectional diagram of the thermal insulation device illustrated in Figure 9, showing the operating principle of the thermal insulation device during deployment mode;

- Figure 12 is a perspective view of a thermal insulation device according to a sixth embodiment, said thermal insulation device being adapted to be supported by a radiator of the spacecraft illustrated in Figure 1;

- Figure 13 is a perspective view of a thermal insulation device according to a seventh embodiment, said thermal insulation device being supported by a radiator of the spacecraft illustrated in Figure 1;

- Figure 14 is a perspective view of two thermal insulation devices according to the seventh embodiment, said thermal insulation device being supported by a radiator of the spacecraft illustrated in Figure 1;

- Figure 15 is a perspective view of a thermal insulation device according to the eighth embodiment, said thermal insulation device being adapted to be supported by a radiator of the spacecraft illustrated in Figure 1;

- Figure 16 is a perspective view of a thermal insulation device according to the ninth embodiment, said thermal insulation device being adapted to be supported by a radiator of the spacecraft illustrated in Figure 1;

- Figure 17 is a perspective view of a thermal insulation device according to the tenth embodiment, said thermal insulation device being adapted to be supported by a radiator of the spacecraft illustrated in Figure 1; and

- Figure 18 is a front view of an eleventh embodiment of a thermal insulation device arranged on a radiator of the spacecraft illustrated in Figure 1.

Referring to Figure 1, a spacecraft 2 according to the invention is in the form of a rectangular box 4. This box 4 always has the same face directed towards the Earth, this face being called the Earth face 6. The opposite face and parallel to the Earth face 6 is in turn called the anti-Earth face 8.

The - X face, also called the East face 10, and the + X face, also called the West face 12, are opposite faces, mutually parallel and perpendicular to the plane of the Equator once the satellite is in its geostationary orbit. Communication antennas 14 are generally fixed on the -X 10 and + X 12 faces. The - Y face, also called the South face 16, and the + Y face, also called the North face 18, are two other faces of the body. They are opposite, parallel to each other and perpendicular to the North-South axis of the Earth.

The spacecraft 2 generally comprises a solar panel 20 and a radiator 22 fixed on the + Y face 18, and a solar panel 21 and a main radiator 23 fixed on the -Y face 16.

The radiators 22, 23 are used to cool electronic equipment contained in the body. This electronic equipment not shown in the figures is thermally connected to the radiators, for example, by means of heat pipes also not shown.

Each radiator 22, 23 of generally parallelepiped shape, has an internal main face fixed to the body and an external main face 24, 25 opposite the internal main face and located on the side of the space outside the spacecraft. With reference to the orthonormal coordinate system illustrated in FIG. 1, the radiators 22, 23 extend in a plane (X, Z). They have longitudinal edges 26.

Referring to Figures 1 and 2, the radiator 22 of the south face 18 supports a thermal insulation device 28 according to a first embodiment of the invention.

This thermal insulation device 28 comprises a first screen device 30 capable of covering a first zone 32 of the radiator and a traction device 34 suitable for controlling the first screen device 30.

The first screen device 30 comprises a thermally insulating sheet 36 fixed to the radiator 22 by fixing means 46, two springs 38 fixed to the insulating sheet, a support rod 40 and two cables 41 integral with the springs.

The thermally insulating sheet 36 is a flexible sheet. It is, for example, made in a Kapton sheet. It has a face capable of reflecting solar radiation and in particular infrared radiation. This reflection face is, for example, produced by depositing a thin layer of aluminum. An external lateral edge 39 of the insulating sheet 36 is fixed to the radiator 22 so that its reflection face is situated towards space. In particular in the example illustrated in FIG. 1, the external lateral edge 39 of the insulating sheet 36 is fixed to a longitudinal edge 26 of the main external face 24 of the radiator 22.

This fixing is implemented by fixing means 46 such as, for example, rivets. The insulating sheet 38 has, for example, a thickness of 50 μm. According to the embodiment shown, the insulating sheet 38 has a rectangular shape of length Lo and width La. The length Lo is measured according to the direction of traction T

With reference to FIG. 3, the springs 38 are springs exerting a constant force, that is to say springs capable of producing a constant reaction force whatever their elongation. They are therefore non-linear springs.

The springs are prestressed by manufacture in order to remain wound on themselves at rest.

The springs are made of metal, for example, stainless steel.

The springs 38 each have the form of a ribbon produced in a thin and flat strip. Each ribbon has a width between 5 and 30 millimeters and, preferably, a width between 10 and 20 millimeters.

The springs 38 have a first end 42 located inside the ribbon winding and a second end 44 located at the outer periphery of the ribbon winding. The first end 42 of each spring is fixed to one end of the support rod 40. The second end 44 is fixed to the radiator by the fixing means 46.

A spring 38 is fixed along a longitudinal edge 43 of the insulating sheet 36. The other spring 38 is fixed along an opposite longitudinal edge 45 of the insulating sheet. As can be seen in FIG. 2, the springs 38 are fixed along their entire length to the insulating sheet, that is to say that a main face of the strip assembly from the first end 42 to the second end 44 is fixed on the insulating sheet.

The support rod 40 is fixed on an internal lateral edge 49 of the insulating sheet opposite to the external lateral edge 39 which is fixed on the radiator.

The cables 41 are each fixed, on the one hand, to the support rod 40 or to the first end 42 of the springs 38 and, on the other hand, to the traction device 34. They are flexible cables. They can, for example, be made of Kevlar or nylon.

The first screen device 30 also comprises at least two first stops 47 capable of wedging the support rods 40 during the launching of the spacecraft. The first stops 47 are fixed on the main external face of the radiator 22 between the insulating sheet 36 and the traction device 34.

The traction device 34 comprises a traction shaft 48 rotatably mounted about an axis of rotation AA, bearings 50 supporting and guiding the traction shaft 48, a device 52 for locking the rotation of the traction shaft around of said axis of rotation and an actuator 54 suitable for driving the traction shaft 48 in rotation.

One end of each cable 41 is fixed to one end of the traction shaft 48. When the first screen device 30 covers the first area 32 of the radiator, the cables 41 are wound on the traction shaft 48.

Pulleys 56 can advantageously be mounted on the traction shaft. When pulleys are mounted on the drive shaft, the cables 41 are fixed and wound on the pulleys 56.

The bearings 50 are fixed to the main external face 24 of the radiators.

The locking device 52 maintains a pre-stress level defined on the first screen device 30 so that the latter endures significant mechanical loads when the spacecraft is launched. This prestressing level is not felt by the actuator 54. The locking device 52 thus makes it possible to avoid tiring the engine of the actuator 54 by mechanical launching loads. Advantageously, this device makes it possible not to oversize the blocking capacities of the motor.

The locking device 52 is a retention and release mechanism generally known in English as "Hold Release Mechanism" or "HRM". It can, for example, be constituted by a shape memory lock which, by shrinking by heating, releases the actuator 54 from its blocking position. Such a locking device is used only once, during the launch of the spacecraft.

As a variant, the springs are only fixed at a few points on the insulating sheet 36.

The actuator 54 is, for example, a stepping motor with a reduction gear. It is suitable for rotating the traction shaft 48 in one direction to deploy the insulating sheet 36 over the first region of the radiator and in a opposite direction to wind the insulating sheet around the support rod 40. In this mode of embodiment, the actuator 54 controls the speed of winding and unwinding of the springs.

When launching the spacecraft, the traction device 34 pulls in a traction direction T on the first end 42 of the springs so that the insulating sheet 36 covers the first zone 32. The traction direction is perpendicular to the drive shaft 48 and is directed towards it. In the example illustrated in the figures, the direction of traction is directed in the direction X of the orthonormal coordinate system (X, Y, Z). The interior of the box 4 is then thermally isolated by the first screen device 30. The thermal insulation device 28 is in an operating mode called deployed mode.

In this deployed mode, the locking device 52 is locked. The support rod 40 is abutted against the first stops 47. The cables 41 are wound around the traction shaft 48 or around the pulleys 56. The insulating sheet 36 and the springs 38 extend unfolded along the first zone 32 of the radiator. The insulating sheet 36 and the springs 38 are then stretched between their second end 44 fixed to the edge 26 of the radiator and their first end 42 pulled by the cables 41. The springs 38 seek to regain their curvature at rest so that they apply a force F directed towards the main external face of the radiator. The insulating sheet 36 is thus pressed against the main external face of the radiator by the springs 38. Advantageously, in this position, the insulating sheet 36 is not necessarily stretched. So that it is not subjected to the crack propagation generated by impacts of micrometeorites.

Once the spacecraft is in orbit, the locking device 52 is unlocked. Then, the thermal insulation device 28 is put into an operating mode, called exposure mode. To this end, the traction device 34 frees the first end 42 of the springs to expose the first zone 32 towards space.

In particular, with reference to FIG. 4, in the thermal insulation device according to this first embodiment, the actuator 54 rotates the traction shaft 48 in a counterclockwise direction Se. The part of cable 41 wound around the traction shaft 48 is unwound. The unwinding of the cables 41 results in the winding of the springs 38. The springs 38 resume their rolled up shape at rest. By resuming their shape at rest, the springs 38 wind with them the insulating sheet 36 and the cables 41, around the support rod 40, as visible in FIG. 4. The cables 41 are inserted between the windings of the springs 38 and of the insulating sheet 36. The cables 41 are stretched constantly because the natural force of the constant force spring keeps them stretched.

The first screen device 30 according to this first embodiment also makes it possible to cover the first zone 32 once the spacecraft is in orbit to isolate the interior of the body 4 in order to meet specific needs. The thermal insulation device 28 is then put into an operating mode, called deployment mode.

To this end, with reference to FIG. 5, the actuator 54 rotates the traction shaft 48 in a clockwise direction Sd. The cables 41 are wound around the traction shaft 48 or around the pulleys 56. The cable 41 pulls on the winding formed by the springs 38, the insulating sheet 36 and part of the cables 41. Under the action of the tension exerted by the cables 41, the springs 38 and the insulating sheet 36 unwind and deploy once again on the first zone 32 of the radiator.

As a variant, the actuator 54 can either control the speed of rotation of the traction shaft 48 according to a single speed value fixed before launching, or offer variable speeds (for example by remote control) according to the needs of the mission. The variability of the speed of rotation can be understood either between two uses of the thermal insulation devices (for example switching to exposure mode or deployment mode), or within the same use in order to offer a acceleration or deceleration capacity (for example when approaching the extreme positions of thermal insulation devices) in order to reduce the duration of the operation.

Referring to Figure 6, the thermal insulation device 58 according to a second embodiment of the invention, is identical to the thermal insulation device 38 according to the first embodiment with the exception that the device traction 60 does not have an actuator 54 but has a damping device 62.

Unlike the thermal insulation device 38 according to the first embodiment, the thermal insulation device 58 according to the second embodiment cannot be put into an operating mode called deployment mode. The thermal insulation device 58 according to the second embodiment is mounted on the spacecraft 2 in a deployed mode configuration. Once in orbit, the thermal insulation device 58 is arranged in exposure mode. Then, the thermal insulation device 58 is held in this position.

The damping device 62 controls the winding speed of the insulating sheet 36 on the support rod 40, during the exposure mode. The damping device 62 consists, for example, of a centrifugal brake or a Foulcault current brake.

In operation, during the exposure mode, the locking device 52 releases the first end 42 of the springs. As the springs 38 seek to resume their shape wound at rest, they exert a constant force on the cables 4 in a direction opposite to the direction of traction T. The traction shaft 48 is rotated by the force exerted by the springs 38. The damping device 62 limits the speed of rotation of the traction shaft 48 and thus regulates the winding speed of the insulating sheet 36 and the springs 38 during the exposure mode.

Advantageously, the actuator 54 and the damping device 62 can be redundant. Thus, the thermal insulation device according to the invention is robust.

According to a variant not shown, the traction device 60 only comprises a pulley and a damping device.

According to another variant not shown, the traction device 34 comprises two flexible cables and two rotary actuators each suitable for controlling the winding of a cable.

As a variant, the thermal insulation device according to the invention comprises an emergency device for cutting cables, not shown. In the event of a breakdown, for example in the event of blockage of one of the elements of the device in a deployment position (ie. Cover of the radiators), this emergency device cuts the cables 41. The preformed springs to fold over them - even ensure that the external surface of the radiators are exposed.

Compared to solutions in which the screen device would be wound / unwound directly on the drive shaft, the device according to the invention is more reliable for the satellite mission. According to the invention, only the cables 41 are wound on the traction shaft. Thus, if the traction device breaks down, it would be possible to use the emergency cable sectioning device so that the screen devices automatically roll up on themselves without the possibility of blocking, thus revealing the radiators . To compensate for this loss of function, it would suffice to simply heat the interior of the satellite using the heaters when necessary. This situation would be far less damaging than cases where thermal shield devices wound on the drive shaft fail in the "deployment mode" position, that is to say completely covering the radiators. In such a situation, following the use of the payload, the temperature inside the satellite could rise significantly and the radiators would be prevented from performing their heat dissipation function, which could then cause irreparable damage to certain electronic equipment.

Referring to Figure 7, the thermal insulation device 64 according to a third embodiment of the invention is identical to the thermal insulation device 38 according to the first embodiment except that it comprises a second screen device 66 capable of using a second zone 68 of the radiator situated in the extension of the first zone 32 in the direction of traction T.

The first 30 and the second 66 screen devices are controlled by the same traction device 34, 60. This traction device 34, 60 may comprise an actuator 54 or a damping device 62.

The first 30 and the second 66 screen devices are located on the same side of the traction shaft 48. In particular, the second screen device 66 is adjacent and in the extension of the first screen device 30 in the direction of traction T.

The second screen device 66 is identical to the first screen device 30 except that the cables 70 of the second screen device have a greater length than the cables 41 of the first screen device. The cables 70 of the second screen device are also fixed to the traction shaft 48 or to pulleys 56 integral with the traction shaft. The winding of the cables 70 of the second screen device on the traction shaft 48 is arranged at a predefined distance from the winding of the cables 41 of the first screen device.

The support rod 40 of the second screen device extends parallel to the support rod 40 of the first screen device 30. In particular, the support rod 40 of the second screen device is adjacent and parallel to the external lateral edge 39 of the insulating sheet 36 of the first screen device.

The second screen device 66 comprises second stops 72 for wedging the support rod 40 of the second screen device. These second stops 72 are fixed on the main external face 24 of the radiator opposite and a few centimeters from the external lateral edge 39 of the insulating sheet 36 of the first screen device 30.

The springs 38 of said second screen device 66 extend parallel to the direction of traction T. In the exposure mode, the springs 38 of the first screen device 30 and the springs 38 of the second screen device 66 are wound on themselves in the same winding direction.

The first 30 and second 66 screen devices of the thermal insulation device according to the third embodiment operate in the same way as the thermal insulation devices according to the first and the second embodiment, the insulating sheets 36 of the two devices screens being controlled simultaneously by the rotation of the traction shaft 48.

Referring to Figure 8, the thermal insulation device 74 according to a fourth embodiment of the invention, is identical to the thermal insulation device 38 according to the first embodiment with the exception that it comprises a second screen device 76 capable of using a second zone 78 of the radiator situated in the extension of the first zone 32 in a direction perpendicular to the direction of traction T.

The first 30 and the second 76 screen devices are controlled by the same traction device 80. The traction device 80 can comprise an actuator 54 or a damping device 62. This traction device 80 comprises a first traction shaft 82 and a second traction shaft 84 mounted on the same axis of rotation AA. The first 30 and the second 76 screen devices are located on the same side of the first and second traction shafts 82, 84.

The second screen device 76 is adjacent and in the extension of the first screen device 30 in a direction perpendicular to the direction of traction T.

According to a variant not shown, the first traction shaft 82 and the second traction shaft 84 are interconnected by means of a gearbox type device. Thus, for a given speed of rotation of the first traction shaft 82, different rotation speed ratios are possible for the second traction shaft 84. This ratio can be fixed before launching or be variable by remote control as required.

According to a variant not shown, the traction device comprises a single traction shaft of length greater than the width La of the insulating sheet of the first screen device 30 plus the width La of the insulating sheet of the second screen device 66.

The cables 41 of the second screen device 76 are fixed to the second traction shaft 84 or to pulleys integral with the second traction shaft 84.

The support rod 40 of the second screen device extends in the extension of the support rod 40 of the first screen device 30.

The second screen device 76 comprises second stops 86 for setting the support rod 40 of the second screen device. These second stops 86 are fixed on the main external face 24 of the radiator opposite and at a short distance from each end of the second traction shaft 84.

The springs 38 of the second screen device 66 extend parallel to the direction of traction T. In the exposure mode, the springs 38 of the first screen device 30 and the springs 38 of the second screen device 66 are wound on themselves in the same winding direction.

The first 30 and second 76 screen devices of the thermal insulation device according to the third embodiment operate in the same manner as the thermal insulation devices according to the first and second embodiments. The insulating sheets 36 of the two screen devices are controlled simultaneously by the rotation of the first 82 and second 84 traction shafts.

Referring to Figure 9, the thermal insulation device 88 according to a fifth embodiment of the invention, is identical to the thermal insulation device 38 according to the first embodiment with the exception that it comprises a second screen device 90 suitable for covering a second zone 92 adjacent to the first zone 32.

The first 30 and the second 90 screen devices are driven in displacement by the same traction device 34, 60. Thus, the insulating sheets of the first 30 and second 90 screen devices are wound on the support rods 40 simultaneously and by the same device traction device 34, 60. This traction device may comprise an actuator 54 or a damping device 62.

In this fifth embodiment, the second screen device 90 is arranged on the other side of the traction device 34, 60. The traction shaft 48 is thus arranged between the first screen device 30 and the second screen device 90.

The second screen device 90 comprises second stops 94 fixed on the radiator on the other side of the traction shaft 48 in line with the first stops 47 of the first screen device.

The support rod 40 of the second screen device 90 extends parallel to the support rod 40 of the first screen device 30.

The first end 42 of the springs of the second screen device is fixed to the support rod 40. The second end 44 of the springs of the second screen device is fixed to the radiator by the fixing means 46. However, the springs 38 of the second screen device are mounted on the insulating sheet in the opposite direction to the springs 38 of the first screen device. And the cables 41 of the second screen device 90 are wound on the traction shaft 48 in a winding direction opposite to the direction of winding of the cables 41 of the first screen device 30. Consequently, the traction device 34, 60 applies a tensile force at the springs 38 of the second screen device in a direction opposite to the direction of traction T.

At rest, the springs 38 of the first screen device are wound on the support rod 40 in a first winding direction S1. The springs 58 of the second screen device are wound on the support rod 40 in a second winding direction S2. The second winding direction S2 is opposite to the first winding direction S1.

According to the example shown in Figure 10, during the exposure mode, the traction shaft 48 is rotated counterclockwise. The springs 58 of the first screen device are wound on the support rod in an anti-clockwise direction. The springs 58 of the second screen device are wound on the support rod 40 in a clockwise direction.

The insulating sheet of the first screen device 30 is wound while moving in a direction opposite to the direction X. The insulating sheet of the second screen device 90 is wound while moving in the direction of the direction X.

Referring to Figure 11, during deployment mode, the traction shaft 48 is rotated clockwise. The springs 58 of the first screen device unwind clockwise. The springs 58 of the second screen device take place in an anti-clockwise direction. The insulating sheet of the first screen device 30 is unrolled while moving in the direction of the direction X. The insulating sheet of the second screen device 90 is unrolled while moving in the direction of the direction X.

According to the third, fourth and fifth embodiments shown in Figures 7 to 9, the insulating sheet 36 of the second screen device 66, 76 has the same length Lo and the same width La as the insulating sheet 36 of the first screen device 30. As a variant, the length Lo and / or the width La of the insulating sheet 36 of the second screen device 66, 76 may be different from the length Lo and / or the width La of the insulating sheet 36 of the first screen device 30.

According to a variant not shown of the third, fourth and fifth embodiments, the insulating sheet 36 of the first screen device 30 has a length Lo greater than the length Lo of the insulating sheet 36 of the second screen device 90. To allow exposure and a deployment by the same traction shaft, the latter carries at least two pulleys with a diameter greater than the diameter of the traction shaft, said cables of the second screen device being wound on these pulleys.

According to another variant not shown of the third, fourth and fifth embodiments, the insulating sheet of the first screen device 30 has a width La greater than the width La of the second screen device.

According to a sixth embodiment of the invention shown in FIG. 12, the thermal insulation device 96 comprises two screen devices located on one side of the traction shaft 48 and two other screen devices located on the other side of the traction shaft. The insulating sheets of these four screen devices are moved by the same traction device 34, 60. This traction device can comprise an actuator 54 or a damping device 62.

According to a seventh embodiment of the invention shown in FIGS. 13 and 14, the thermal insulation device 98 comprises four screen devices and a traction device 80 capable of moving the four screen devices at the same time.

The traction device 80 has a first traction shaft 82 and a second traction shaft 84. The second traction shaft 84 is mounted on the same axis AA as the first traction shaft 82. A first 30 and a second 90 screen devices are arranged on either side of the first traction shaft 82. A first 30 and a second 90 screen devices are arranged on either side of the second traction shaft 84.

FIG. 14 shows an example of the use of two thermal insulation devices 98 according to the seventh embodiment of the invention on the same radiator of a spacecraft.

With reference to FIG. 15, the thermal insulation device 99 according to an eighth embodiment of the invention is identical to the thermal insulation device 38 according to the first embodiment except for the fact that the insulating sheet 36 further comprises an opening 101, that the support rods 40 have a length greater than the width

The of the insulating sheet and that it further comprises two ramps 100, 102 fixed to the main external face of the radiator.

The ramps 100, 102 extend in the direction of traction T on either side of the longitudinal edges 43, 45 of the insulating sheet.

The ramps 100, 102 have ramp portions 104 which extend projecting relative to the radiator. In particular, the ramp portions 104 extend in a plane perpendicular to the main external face of the radiator 22, 23. The ends of the support rods are capable of coming to bear against said ramps 100, 102 during the mode of exhibition or during deployment mode. Thus, advantageously, the ramps 100, 102 make it possible to pass the support rod over an obstacle in the positioning or winding of the insulating sheet.

When the screen device is in a deployed mode and the insulating sheet covers the area of the radiator to be insulated, the springs and the insulating sheet are pressed against the radiator. The opening 101 is crossed by an equipment projecting from the radiator such as for example a transmitter.

As a variant, the springs bear against the ramps.

With reference to FIG. 16, the thermal insulation device 106 according to a ninth embodiment of the invention is identical to the thermal insulation device according to the seventh embodiment except for the fact that one of the devices screens attached to the second traction shaft 84 is replaced by a first gear mechanism 108 attached to the free end of the second traction shaft 84, a bevel gear 110 coupled to the first gear mechanism 108, a third traction shaft 116 having a second gear mechanism 114 coupled to the bevel gear 110 and two additional screen devices 116 fixed by cables to the third traction shaft 116. The additional traction shaft 116 extending along the traction direction T.

With reference to FIG. 17, the thermal insulation device 118 according to a tenth embodiment of the invention is identical to the thermal insulation device according to the seventh embodiment except that one of the sheets insulators 36 has one or more cutouts 120. In this embodiment, the support rod is shorter and the spring extends partly over the longitudinal edge of the insulating sheet and partly inside the insulating sheet . This embodiment makes it possible not to deliberately cover part of the radiator or to bypass equipment which could be fixed to the radiator 22. Such equipment is for example a transmitter or an arm of a solar panel.

FIG. 18 represents an example of the use of a thermal insulation device 122 fixed to a radiator 22 of a spacecraft. This thermal insulation device 122 has a single traction shaft 48, six screen devices 124, 126, 128, 130, 132, 136 arranged to the right of the single traction shaft 48 and five screen devices 138, 140, 142, 144, 146 arranged to the left of the traction shaft.

As a variant, it is also possible to use traction shafts 48 whose diameter is not uniform over their entire length. In the case of an embodiment using several screen devices, this makes it possible, for the same speed of rotation of the traction shaft 48, to obtain very simply and very effectively different unwinding speeds of the cables (and therefore different screen devices).

The operation of the thermal insulation devices described in the invention can be controlled in several ways: either by sending remote controls from the ground, or automatically from the edge via an internal thermal control device to the satellite .

The purpose of such a check (from the ground or from the edge) is to determine when the following operations are carried out:

• unlocking the unlocking device 52 • switching to a deployment mode or an exposure mode, for what duration, with what range of movement (partial or full deployment) and for which screen device.

The advantage of the thermal insulation device according to the invention is its simplicity and genericity, making it possible to make numerous savings in qualification and assembly time, and in reducing risks on satellite programs using such devices. Indeed, the invention uses a basic module which can be qualified once and for all. Each new satellite program can then combine, like a puzzle, one or more of these devices according to the external configuration of the satellite walls, while benefiting from the prior qualification of the basic module.

The invention could also be used as a thermal insulation device on the X faces of satellites, and also as a thermal blanking system for optical instruments such as telescopes.

The device according to the invention is applicable for telecommunications or observation satellites operated on any type of orbit (LEO, MEO, HEO, GEO), and also for scientific space missions (probes) having long transfer times .

Claims (18)

1 spacecraft (2) comprising a box (4) having at least one face (16, 18), at least one radiator (22, 23) carried by said face (16, 18), and at least one thermal insulation device (28,58,64,74,88,96,98,99,106,118,122) carried by the radiator (22,23), characterized in that said thermal insulation device (28,58,64,74,88,96, 98, 99,106,118,122) includes: - a first screen device (30) capable of covering a first zone (32) of said radiator (22, 23), said first screen device (30) comprising a thermally insulating and flexible sheet (36) and at least two springs (38 ) capable of producing a constant reaction force, said springs (38) being preformed so as to roll up on themselves at rest, said springs (38) being fixed on the insulating sheet (36), said springs (38) each having a first end (42) fixed to a traction device (34,60) and a second end (44) fixed to the radiator (22, 23); and - a traction device (34, 60) suitable for pulling in a traction direction (T) on the first end (42) of said springs of the first screen device so that the insulating sheet (26) covers the first area (32) in a mode called deployed mode, said traction device (34, 60) being able to release the first end (42) of said springs to expose the first zone (32) towards space in a mode called exposure mode. 2, - spacecraft (2) according to claim 1, wherein the first screen device (30) comprises at least two cables (41), each cable being integral with said traction device (34,60) and the first end ( 42) springs, said cables (41) being interposed between two windings of the springs (38) in the exposure mode. 3. - spacecraft (2) according to any one of claims 1 and 2, wherein the first screen device (30) further comprises a support rod (40) extending in a direction perpendicular to the direction of traction (T) and at least two first stops (47) fixed on the radiator (22, 23) between the insulating sheet (36) and the traction device (34,60), said first stops (37) being adapted to wedge the support rod (40) during the launch of the spacecraft. 4. - spacecraft (2) according to any one of claims 1 to 3, in which the traction device (34,60) comprises: - a traction shaft (48) rotatably mounted about an axis of rotation (AA), said traction shaft (48) extending perpendicular to the direction of traction (T), the first end (42) of said springs ( 38) being integral with said traction shaft (48); and - a locking device (52) for the rotation of the traction shaft (48) about said axis of rotation (A-A). 5. - spacecraft (2) according to claim 4, wherein the traction device (34) comprises an actuator (54) capable of rotating the traction shaft (48). 6. - spacecraft (2) according to claim 4, wherein the traction device (60) further comprises a damping device (62) capable of damping the rotation of the traction shaft (48), when the locking device (52) is unlocked. 7. - spacecraft (2) according to any one of claims 1 to 6, wherein the thermal insulation device (64,74) further comprises a second screen device (66,76) capable of covering a second area (68,78), said second screen device (66,76) being identical to the first screen device (30), the springs (38) of said second screen device (66,76) extending parallel to the direction of traction (T ). 8. - spacecraft (2) according to claim 7, in which the first screen device (30) and the second screen device (66,76) are arranged on the same side of the traction device (34, 60), and in which, in the exposure mode, the springs (38) of the first screen device and the springs (38) of the second screen device (66,76) are wound on themselves in the same winding direction. 9. A spacecraft (2) according to claim 8, wherein the insulating sheet (36) of the second screen device (66) is arranged in the extension of the insulating sheet (36) of the first screen device (30) in the direction. of traction (T). 10. - spacecraft (2) according to claim 8, wherein the insulating sheet (36) of the second screen device (76) is arranged in the extension of the insulating sheet (36) of the first screen device (30) in a direction perpendicular to the direction of traction (T). 11. - spacecraft (2) according to claim 7, wherein the traction device (34, 60) is arranged between the first screen device (30) and the second screen device (90) and in which, in the mode d exposure, the springs (38) of the first screen device roll up on themselves in a first winding direction (S1) and the springs (38) of the second screen device roll up on themselves according to a second winding direction (S2), the second winding direction (S2) being opposite to the first winding direction (S1). 12. - spacecraft (2) according to the combination of claims 2, 4 and 11, wherein the insulating sheet (36) of the first screen device (30) has a length (Lo) greater than the length (Lo) of the sheet insulating (36) of the second screen device (66, 76, 90), said length (Lo) being measured in the direction of traction (T), and in which the traction shaft (48) supports at least two pulleys of diameter greater than the diameter of the traction shaft (48), said cables of the second screen device (66, 76, 90) are wound on said pulleys. 13. - spacecraft (2) according to any one of claims 11 and 12, wherein the insulating sheet (36) of the first screen device (30) has a width (La) greater than the width (La) of the second device screen (66, 76, 90), said width (La) being measured in a direction perpendicular to the direction of traction (T). 14. - spacecraft (2) according to any one of claims 11 to 13, wherein the first screen device (30) comprises at least two ramps (100, 102) fixed to the radiator (22, 23) in a parallel direction in the direction of traction (T), at least one of the springs (38) and the ends of the support rods being able to come into abutment against said ramps (100, 102) in the deployed mode, said ramps (100 , 102) having ramp portions (104) which project from the radiator (22, 23). 15. - spacecraft (2) according to any one of claims 1 to 14, wherein at least one edge of the insulating sheet has at least one cutout. 16. - spacecraft according to any one of claims 4 to 15, which comprises a first gear mechanism (108) fixed to the free end of a traction shaft (84), an angle transmission device (110) coupled to the first gear mechanism (108), an additional drive shaft (112) having a second gear mechanism (114) coupled to the bevel gear (110) and at least one additional screen device (116) fixed by cables to the additional traction shaft (112); the additional traction shaft (112) extending in the direction of traction (T). 17. - spacecraft (2) according to any one of claims 1 to 16, wherein said springs (38) are flat strips of stainless steel in the form of a ribbon, said strips having a width of between 5 and 30 millimeters. 18. - spacecraft (2) according to any one of claims 1 to 15, wherein the insulating sheet (36) is a Kapton sheet covered with a layer of aluminum. 1/12 22.24 ÀY