OUTPUT SYSTEM FOR A SATELLITE

Description

[0001] Satellites are widely used today for a multitude of applications. Until a few years ago, predominantly large, expensive satellites, the construction of which could take decades, were employed. The Iridium satellites serve as an example; each satellite body is approximately four meters long and over one meter in diameter, weighing over 650 kg. The cost of a single Iridium satellite amounted to several tens of millions of US dollars.

[0002] Modern satellites often weigh less than 500 kg (such as the satellites of SpaceX's Starklink system, each weighing approximately 230 kg). The current trend is toward so-called micro- and nanosatellites, with microsatellites weighing between 10 kg and 100 kg, and nanosatellites between 1 kg and 10 kg. A well-known example of nanosatellites are the so-called "CubeSats." These adhere to a standardized maximum weight (1.33 kg) and standardized external dimensions (10 x 10 x 10 cm). Micro- and nanosatellites can be built and launched into orbit relatively quickly and cost-effectively.

[0003] Especially in the field of nanosatellites, but also with microsatellites and traditional satellites, it is advantageous to save as much weight and space as possible. This allows a larger number of satellites to be carried on a single launch vehicle, thereby significantly reducing the cost of transporting each satellite into space.

[0004] In many applications, it is advantageous or even necessary to operate a satellite's functional element at a distance from its main body. Such a functional element can be a data generator like a sensor, for example, a temperature, acceleration, attitude, and / or radiation sensor, or an antenna. Other examples of functional elements include solar sails or panels and braking parachutes.

[0005] To position such a functional element in its operational position away from the satellite main body, a boom can be used, attached at one end to the functional element and at the other end to the satellite main body. For example, the boom can be designed as a foldable ladder or frame structure, so that it occupies less space in a prepared position than in the functional element's operational position. An example of a large foldable ladder structure is the so-called "Folding Articulated Square Truss (FAST)" mast, which is currently used on the International Space Station (ISS) to support solar panels.

[0006] US patent 2016 / 024790 A1 discloses a deployable structure with a spring band. US patent 2018 / 111703 A1 discloses a boom system with a coiled, stored boom. US patent 2020 / 122861 A1 discloses a device in which spring bands are coiled and stored, forming a boom structure after uncoiling. CN patent 209 213 333 U discloses a robot-arm-like boom structure for satellites.

[0007] Against this background, the task is to provide a cost-effective, compact and functionally improved boom system for a satellite.

[0008] A boom system for a satellite is provided, comprising a boom that is wound in multiple layers in a coiled state and unwound in an unwound state. The boom is designed to assume a predetermined shape in the unwound state under weightlessness. Thus, the boom can be unwound or unfolded from its coiled state.

[0009] Preferably, the boom is essentially ribbon-shaped, at least in its wound state, and also, for example, in its unwound state. In its wound state, the boom can be wound radially in multiple layers. In its wound state, the boom can also be wound in multiple layers in a helical or spiral shape.

[0010] The boom system includes a spring accumulator that provides the force required to unwind the boom from its coiled to its uncoiled state. In other words, the spring accumulator provides the force needed to extend the boom.

[0011] The spring storage system makes it possible to do without an electric motor for unwinding the boom, which at least minimizes the susceptibility to errors, the weight and the manufacturing costs.

[0012] The spring storage unit can include a bending spring, for example, a coil spring. The bending or coil spring can be made of a strip-shaped metallic material (e.g., spring steel). For example, the bending or coil spring is rotationally fixed to the boom. For this purpose, the bending or coil spring can be directly or via a connecting element rigidly connected to the boom in a rotationally and / or tensile-resistant manner.

[0013] In one example, the boom, when wound up, forms a spiral running in the opposite direction to the coil spring.

[0014] For example, when the boom is wound up, the coil spring and the wound boom essentially revolve around the same axis. The radial and axial directions and distances described herein can refer to this axis.

[0015] For example, superimposed layers of the wound cantilever each have the same radial spacing. Individual windings of the spiral spring can have different radial spacings from one another.

[0016] The cantilever system can include a bearing journal extending along the axis, with a radially internal end section of the bending or coil spring fixed or attached to the bearing journal. The bearing journal is, for example, rotationally fixed relative to the cantilever and the bending or coil spring, at least during the unwinding of the cantilever. For example, the bearing journal is rotationally fixed and axially releasable to a mounting plate. This allows the bending or coil spring to be wound by rotating the bearing journal before mounting on the mounting plate. In other words, rotating the bearing journal relative to the bending or coil spring allows spring tension to build up in the bending or coil spring. Counter-rotation of the bearing journal can be prevented by mounting it on the mounting plate, as this fixes the bearing journal rotationally fixed relative to the bending or coil spring.

[0017] The bending or spiral spring can be arranged entirely or substantially completely radially inside the wound-up boom when the boom is wound up.

[0018] The boom system can include a guide disc that is perpendicular to the axis and, in the wound-up state of the boom, covers the boom and / or the bending or coil spring in an axial plan view. The guide disc can be part of an empty spool, with the boom being wound onto the empty spool in the wound-up state. For example, in the wound-up state of the boom, the guide disc is under a spring preload provided by the spring storage element, in particular the bending or coil spring.

[0019] The boom system can include a fastening element that is attached to both the guide disc and the bending or coil spring. For example, when the boom is wound up, the fastening element is under spring tension provided by the spring storage, in particular the bending or coil spring.

[0020] The boom, in particular a radially inner end section (e.g., the first) when the boom is wound up, can be attached to the fastening element and / or to the bending or coil spring in the area of ​​the fastening element. Alternatively or additionally, the boom, or a radially inner end section (e.g., the first or second) when the boom is wound up, can be attached to the guide disc.

[0021] For example, the boom, or a radially inner end section of the boom (e.g., first, second, or third) when the boom is wound up, rests radially on the outermost mounting element, at least when wound up. The mounting element can therefore be part of the empty coil. Alternatively or additionally, the boom, or a radially inner end section of the boom (e.g., first, second, third, or fourth) when the boom is wound up, can rest on an outermost radial winding of the coil spring, at least when the boom is wound up.

[0022] The boom system can comprise one or more guide elements attached to the guide pulley. For example, the boom, or a radially inner end section of the boom (e.g., first, second, third, fourth, or fifth) when wound, rests radially outer on one or more guide elements when wound. The one or more guide elements can be part of the empty spool.

[0023] In one example, the cantilever system includes a rolling bearing (e.g., a roller bearing) or a ball bearing that allows the guide disk to rotate around the axis. For example, the rolling or ball bearing is designed to limit the translation of the guide disk along the axis (e.g., in one or two directions).

[0024] The boom system can include electrical wiring extending from a first longitudinal end of the boom to a second longitudinal end. The wiring can run parallel to the boom at a maximum distance of a few centimeters (e.g., 1, 2.5, or 5). The wiring can be attached to the boom for essentially its entire length. The wiring can include one or more flat flexible cables (FFCs). An electrical load or data generator, such as an image, temperature, acceleration, position, and / or radiation sensor, a digital camera, or a (transmitting and / or receiving) antenna, can be connected to the electrical wiring, particularly to one end of the wiring. For example, the data generator may be attached to one longitudinal end of the boom.

[0025] The cabling enables the trouble-free operation of a connected data generator, and its mounting prevents blockages when the boom is unfurled. The cabling also allows for the operation of a wired data generator, eliminating the need for additional radio modules in the satellite. Ultimately, this also saves on size, weight, and construction costs.

[0026] The cantilever system can include a first cable section connected to and following a spiral path of the coil spring, which is connected to the electrical wiring. The first cable section can comprise one or more ribbon cables.

[0027] For example, the first cable section is essentially attached to the coil spring along its entire length, for example on a radial and / or axial surface of the coil spring.

[0028] The cantilever system can include a second cable section, connected to and electrically linked with the first cable section, which runs axially in the region of a radially inner end of the coil spring. The second cable section can comprise one or more ribbon cables.

[0029] For example, the second cable section is arranged in a rotationally fixed manner relative to the bearing journal. The second cable section can be arranged and / or fastened on a sheath surface of the bearing journal or within the bearing journal.

[0030] In one variant, the boom is made of a composite material. In this variant, the cabling can be embedded in the composite material or attached to a surface of the boom. The composite material can be a plastic composite, for example, a glass fiber, carbon fiber, or natural fiber reinforced plastic.

[0031] In a second variant, the boom is made of a metallic material (e.g., spring steel). In this variant, the cabling can be attached to a surface of the boom. The metallic material can be electrically grounded, particularly in relation to the data generator and / or a ground wire of the electrical cabling.

[0032] According to the invention, the boom system comprises a digital camera attached to a longitudinal end or end section of the boom such that its line of sight, when the boom is unwound, points substantially in the direction of the boom. For example, when the boom is unwound, the line of sight runs parallel to an unwound portion of the boom or is tilted at an acute angle relative to the unwound portion. The angle between the line of sight of the digital camera and the unwound portion of the boom, or between the digital camera and the boom in its unwound state, is, for example, less than 90°, preferably less than or equal to 45°, and in particular less than or equal to 25°, for example less than or equal to 10°. The line of sight can be deflected from the digital camera by one or more mirrors, in which case the last deflected portion points substantially in the direction of the boom.The line of sight lies, for example, in the center of an image taken by the digital camera.

[0033] The digital camera can be electrically connected via the electrical wiring. A control unit can be provided that is connected to the digital camera via the electrical wiring. In particular, the control unit can be electrically connected to the second cable section, with the electrical wiring being connected to the digital camera. The control unit can be configured to send data to the digital camera and / or receive data from the digital camera, such as image data. The digital camera can be powered via the electrical wiring.

[0034] The digital camera can capture an image of a satellite in which the boom system is integrated. This enables optical monitoring of various functions and functional elements of the satellite. For functional analysis, it is therefore not necessary to rely solely on satellite-internal sensor data (e.g., status sensors of a motor used to deploy the boom). Function and functional element monitoring can be optimized, and the use of various status sensors in the functional elements captured by the camera can be eliminated. This also allows for savings in size, weight, and construction costs.

[0035] The boom can be designed as a bistable element, so that in the wound state and in the unwound state it has a lower deformation energy than in any other state of the boom.

[0036] The predetermined shape of the boom can be essentially straight and / or essentially tangential to a radially outermost winding of the spiral spring.

[0037] The boom system may include a guide mechanism designed to guide the boom so that, in its unfurled state, it has the predetermined shape. For example, the guide mechanism may include at least two substantially parallel guide rollers positioned on opposite sides of the boom.

[0038] The guide mechanism, in particular one or both of the guide rollers, can be configured to permit or effect a change in the cross-sectional shape of the coiled boom when it is unwound. For example, a coiled portion of the boom always has a substantially rectangular cross-sectional shape. An unwound portion of the boom can have a curved and / or substantially U-shaped cross-sectional shape. For example, the boom has a cross-sectional shape that substantially corresponds to that of a steel tape measure.

[0039] The boom system can include a locking system which, in a locked state, blocks the unwinding of the wound boom and, in an unlocked state, allows the unwinding of the wound boom. For this purpose, the locking system can be coupled to the guide pulley in a way that allows it to be unlocked. In particular, the locking system can include a locking pin that is in contact with the guide pulley in the locked state of the locking system or in the wound state of the boom. The locking system can include an actuator that releases the locking pin from contact with the guide pulley to move the locking system from the locked to the unlocked state. The locking system can be a so-called "pin puller," whose pin corresponds, for example, to the locking pin described here. For example, the locking system includes the one described in the document dated 31.The actuator module described in the application DE 10 2020 000 688.4, filed in January 2020, is described therein. The release element described therein can correspond to the aforementioned blocking pin.

[0040] The cantilever system can comprise a plurality of cantilevers wound in alternating layers in the wound state. For example, in addition to the cantilever described above, the cantilever system comprises a second cantilever that is wound in multiple layers in the wound state and unwound in the unwound state. The second cantilever is configured to assume a second predetermined shape in the unwound state under weightlessness, with the cantilever in the wound state and the second cantilever in the wound state forming alternating layers. The second cantilever can have the same or different features as the cantilever described above. Preferably, the predetermined shape of the cantilever differs from the predetermined shape of the second cantilever at least in that the cantilever in the unwound state extends in a different direction than the second cantilever.For example, the first boom and the second boom run parallel to each other, spaced apart, in opposite directions. The lengths of the extended booms can be essentially the same.

[0041] Furthermore, a satellite comprising the boom system described herein will be provided. The satellite is, for example, a microsatellite or a nanosatellite.

[0042] The satellite can comprise a main body in which the boom system is located. For example, the boom extends away from the main body when unfurled. The digital camera can be configured and / or attached to the boom in such a way that it can capture an image in which the main body of the satellite is at least partially included.

[0043] In other words, a satellite can be provided with a data generator comprising a digital camera, which can be extended from a preparation position to an operating position by means of a boom, wherein the boom has a flexibly bendable strand body wound into a coil in the preparation position of the data generator, which is connected to the data generator in the region of its outer coil end, wherein when the strand body is unwound its unwound strand parts assume a substantially straight-line orientation (e.g. the predetermined shape described above) that is stable under space conditions (e.g. weightlessness), wherein the strand body is associated with a force source comprising the spring storage for providing a driving force to drive the coil for unwinding the strand body.

[0044] The invention is further explained below with reference to the accompanying drawings. These depict: Fig. 1 a schematic view of a cantilever system; Fig. 2 a cross-sectional view of the cantilever system Fig. 1 ; Fig. 3a a schematic view of part of the boom system; Fig. 3b a schematic view of part of a cantilever system; Fig. 4 a perspective view of the boom system; and Fig. 5 A schematic representation of a satellite with the boom system.

[0045] In the following, unless otherwise explained, the same reference symbols denote the same structural and functional features.

[0046] Fig. 1 shows a schematic representation of a boom system 100 for a satellite, Fig. 2 a sectional view along line AA in Fig. 1 The boom system 100 comprises a boom 2, which in these two figures is shown in a wound-up state. In this state, the boom 2 is wound in multiple layers, while in an unwound state it is unwound.

[0047] It is understood that in the wound-up state, an outermost or radially outermost end section 2a of the boom 2 can run in a straight line. In other words, the radially outermost end section 2a of the boom, in the wound-up state of the boom, is, for example, not part of the winding formed by the wound-up main part of the boom 2 (not visible in Fig. 1 It can be said that the boom 2 is predominantly wound up in its coiled state (e.g., to more than 75%, preferably to more than 80%, or even to more than 90% of the total length of the boom 2). A similar situation applies to the unwound state, in which an inner or radially innermost end section 2b (not visible in Fig. 1 The curve of the boom 2 can be circular or spiral. It can be said that the boom 2 is predominantly unwound in its unwound state (e.g., more than 75%, preferably more than 80%, or even more than 90% of the total length of the boom 2).

[0048] The boom system 100 includes a spring accumulator 4, which provides the force required to unwind the boom 2 from the wound state to the unwound state. As in Fig. 1 As can be seen, the boom system includes a guide disc 6 which covers a wound part of the boom 2 and the spring storage unit 4 in axial plan view.

[0049] The guide disc 6 is supported by a rolling bearing (e.g., roller bearing) 8. The rolling bearing 8 also limits the translation of the guide disc along the axis of rotation. A ball bearing can also be used instead of the rolling bearing 8.

[0050] The boom 2 is designed to assume a predetermined shape in its unfurled state under space conditions (e.g., in a vacuum and weightlessness). This predetermined shape is particularly stable under weightlessness and is essentially straight.

[0051] The boom system 100 comprises a guide mechanism 9 designed to guide the boom 2 such that the boom 2 assumes the predetermined shape in its unwound state. The guide mechanism 9 includes two substantially parallel rotatable guide rollers 10, 12 positioned on opposite sides of the boom 2. Additional bearing rollers 14, 16 are provided to support a wound portion of the boom 2 in a radial direction.

[0052] One or both of the guide rollers 10, 12 are configured to permit or effect a change in the cross-sectional shape of the coiled boom 2 when it is unwound. While a coiled portion of the boom 2 always has a substantially rectangular cross-sectional shape, an unwound portion of the boom 2 has a curved and / or substantially U-shaped cross-sectional shape. Furthermore, the boom 2 is designed as a bistable element, such that it exhibits lower deformation energy in both the coiled and unwound states than in any other state of the boom. In this respect, the boom 2 can be compared to a rolling steel measuring tape.

[0053] The boom system 100 comprises a locking system 17 which, when the locking system 17 is locked and the boom 2 is simultaneously wound up, blocks the unwinding of the wound boom 2, and when the locking system 17 is unlocked, allows the unwinding of the wound boom 2. For this purpose, the locking system 17 is coupled to the guide disc 6 in a way that allows it to be unlocked. In particular, the locking system 17 comprises a locking pin 18 which, when the locking system 17 is locked, is in contact with the guide disc 6 and blocks its rotation. The locking pin 18 can be retracted by an actuator 20 of the locking system 17, thereby releasing the guide disc 6 and allowing its rotation.

[0054] The locking system 17 is mounted on a mounting plate 22. The guide rollers 10, 12 and the bearing rollers 14, 16 are also arranged on the mounting plate 22. Fig. 1 Two housing walls 24, 25 are also indicated, which enclose the wound-up boom. The housing walls 24, 25 can be outer walls of a satellite and are shown in Fig. 2 Not shown for the sake of simplicity. Fig. 2 Furthermore, a housing cover 27 is shown, which runs parallel and axially spaced from the mounting plate 22.

[0055] In the illustrated embodiment, the boom system 100 comprises a plurality of booms 2, 26. These are wound one on top of the other in alternating layers when wound up. In other words, the Fig. 1 The illustrated boom system 100 includes, in addition to the boom 2 described above, a second boom 26, which is wound in multiple layers in its coiled state and unwound in its unwound state. The second boom 26 is configured to assume a second predetermined shape in its unwound state under weightlessness, with the boom 2 and the second boom 26 forming alternating layers in their coiled state. The second boom 26 can have the same features as the boom 2. In its unwound state, the second boom 26 extends parallel to and spaced apart from the second boom 26 in the opposite direction.

[0056] As in Fig. 1 As shown, the boom system 100 includes a digital camera 28. This is attached to the outer end section 2a of the boom 2 and its lens points towards the wound boom 2 or towards the axis of rotation of the guide disk 6.

[0057] Fig. 3a shows part of the system from the Fig. 1 and 2 However, in this view, a central part of the guide disc 6 is shown transparently. This makes the spring accumulator 4 easier to see.

[0058] The spring accumulator 4 comprises a coil spring 29 made of strip-shaped spring steel. In its wound state, the cantilever 2 forms a spiral extending in the opposite direction to the coil spring 29, with the coil spring 29 and the wound cantilever 2 rotating around the axis of rotation of the guide disk 6. In the wound state of the cantilever, the coil spring 29 is arranged entirely radially within the wound cantilever 2. The cantilever system 100 comprises a bearing journal 30 extending in the direction of the axis of rotation of the guide disk 6, with a radially inner end section 29b of the coil spring 29 being attached to the bearing journal 30.

[0059] The bearing journal 30 is fixed to the mounting plate 22 in a rotationally fixed manner. Before mounting the bearing journal 30 and the coil spring 29 on the mounting plate 22, the coil spring 29 can be placed under mechanical tension or wound up by rotating the bearing journal (in Fig. 3a counterclockwise). After winding, the bearing pin 30 can be prevented from rotating in the opposite direction by its mounting on the mounting plate 22. A radially outer end section 29a of the coil spring 29 is coupled to the guide disc 6, so that the guide disc 6 is under spring tension when the boom 2 is wound up or after the coil spring 29 has been wound up. However, the guide disc 6 is prevented from being driven by the coil spring 29 by the locking system 17 (in Fig. 3a (clockwise). Only when the locking system 17 is unlocked can the guide disc 6 rotate under the influence of the spring force of the coil spring 29. The radially inner end section 2b of the boom 2, which is located in the wound-up state of the arm 2, is coupled to the guide disc 6 in a force-transmitting manner. Therefore, the arm 2 is unwound during the spring-driven rotation of the guide disc 6.

[0060] In the illustrated embodiment, the cantilever system 100 comprises a fastening element 32, which is attached to both the guide disc 6 and the radially outer end section 29a of the coil spring 29. A bolt 34 is provided for fastening the fastening element 32 to the guide disc 6. The fastening element 32 is also under spring preload when the cantilever 2 is wound up or after the coil spring 29 has been wound up. The radially inner end section 2a of the cantilever 2 is attached to the fastening element 32 or, in the area of ​​the fastening element 32, to the coil spring 29.

[0061] The boom system 100 comprises several guide elements 36, 38, 40, each of which is attached to the guide disc 6 by bolts 42, 44, 46. The guide elements 36, 38, 40 can be structurally identical to the fastening element 32. For example, the boom 2, or rather the radially inner end section 2a of the boom 2 when wound up, rests radially outer on the guide elements 36, 38, 40 when wound up.

[0062] The guide elements 36, 38, 40 and the fastening element 32 serve as spacers between the guide disc 6 and a guide disc 48 that is axially spaced from and parallel to the guide disc 6. A wound portion of the cantilever 2 and the spiral spring 29 are enclosed and guided axially by the guide disc 6 and the guide disc 48. The guide elements 42, 44, 46, the fastening element 32, the guide disc 6, and the guide disc 48 form an empty coil, wherein the cantilever 2, in its wound state, is wound around the guide elements 42, 44, 46 and the fastening element 32 of the empty coil, and the empty coil is bounded axially by the guide discs 6 and 48.

[0063] Fig. 3b This shows a schematic view of part of a boom system. The boom system shown corresponds, for example, to boom system 100.

[0064] Fig. 4 shows a perspective view of part of the cantilever system 100. As in Fig. 4 As indicated, the boom system includes an electrical cable 50 extending from a first longitudinal end of the boom 2 to a second longitudinal end of the boom 2, and which is attached to the boom 2 along essentially its entire length. The cable 50 is designed as a flexible ribbon cable and is electrically connected to the digital camera 28. The cable 50 is configured to supply power to the digital camera 28 and to transmit data to and from the digital camera 28.

[0065] The cantilever system 100 comprises a first cable section 50a, which is connected to and electrically linked with the electrical wiring 50 and follows a spiral path of the spiral spring 29. The first cable section 50a is designed as a flexible flat cable and is attached to a radial surface of the spiral spring 29 along essentially its entire length (see figure). Fig. 3a The length of the first cable section 50a thus corresponds essentially to the length of the coil spring 29. The length of the coil spring 29 is essentially constant. In other words, the length of the coil spring 29 in the unwound state of the boom 2 does not differ significantly from its length in the wound state of the boom 2. The aforementioned arrangement of the first cable section 50a thus ensures that no mechanical stresses or compressions occur in the first cable section 50a when the boom 2 is unwound or wound up.

[0066] The cantilever system 100 comprises a second cable section 50b, which adjoins and is electrically connected to the first cable section 50a and runs axially in the region of a radially inner end of the coil spring 29 or in the region or at the end of the end section 29b. The second cable section 50b is also designed as a flat ribbon cable. The second cable section is arranged either on a sheath surface of the bearing journal 30 or within the bearing journal 30. In particular, the second cable section 50b is arranged in a rotationally fixed manner relative to the bearing journal 30, for example, by being attached to it and / or to the mounting plate 22. Thus, the second cable section 50b is immovable relative to the bearing plate 22, even though the wiring 50 and the first cable section 50a move relative to the bearing plate 22 when the cantilever is unwound or wound up.In other words, the second cable section 50a represents an electrical connection point for the first cable section 50a that is fixed relative to the bearing pin 30 and / or the mounting plate.

[0067] The first and second cable sections 50a, 50b make it possible to electrically contact the wiring 50 attached to the boom 2 without the use of sliding contacts.

[0068] In this embodiment, the boom 2 is made of spring steel, and the wiring 50 is attached to a surface of the boom. The spring steel is electrically grounded, thereby minimizing electrical interference signals emanating from the boom 2.

[0069] Alternatively, the boom 2 could consist essentially of a fiber composite material. In this case, it would be conceivable to embed the cabling 50 in the fiber composite material.

[0070] Fig. 5 shows a satellite 500 with a satellite main body 502 and the boom system 100 arranged therein. As in Fig. 5 As shown, the predetermined shape of the unwound boom is essentially straight and tangential to a radially outermost winding of the spiral spring 29 or to the end section 29a of the spiral spring 29. In the unwound state shown, the boom 2 extends away from the satellite main body 502. A viewing axis 52 of the digital camera 28 runs parallel to the unwound part of the boom 2. A viewing area 54 of the digital camera 28 encompasses the satellite main body 502 of the satellite 500. Thus, the digital camera can capture an image in which the satellite main body is at least partially, and preferably completely, depicted.

[0071] The spring-driven approach described here eliminates the need for an electric motor to extend the boom. This saves weight, size, and costs.

[0072] The cabling enables the cantilever system to be used with wired data generators, thus expanding its range of applications. Depending on the cabling design, sliding contacts, which are typically required to electrically connect a rotating element, can be completely eliminated. The cabling allows for low-interference, cost-effective, and compact electrical contacting of a data generator located away from a satellite, at low cost, with minimal weight and size.

[0073] By using a backward-facing digital camera as a data source, it is possible to capture images of the satellite's main body. This allows for sharp images of the satellite in orbit and enables visual monitoring of various satellite functions and components. This improves the satellite's operational reliability. Sensors otherwise required for functional monitoring can be eliminated, which in turn saves on size, weight, and cost.

[0074] Features of the exemplary designs, embodiments, and examples described herein can be combined with one another. It is also understood that the boom system need not possess all of the features listed above with reference to the figures.

Claims

1. Boom system (100) for a satellite (500), comprising: a boom (2) which in a furled state is furled in multiple layers and in an unfurled state is unfurled, wherein the boom (2) is adapted to assume a predetermined shape in the unfurled state in zero gravity, wherein the boom system (100) comprises a spring energy store (4) which provides a force necessary to unfurl the boom (2) from the furled state into the unfurled state, characterised in that the boom system (100) further comprises a digital camera (28) which is fastened to a longitudinal end of the boom (2) or to an end portion of the boom (2) in such a manner that its viewing axis (52) points substantially in the direction of the boom (2) in the unfurled state of the boom (2).

2. Boom system (100) according to claim 1, wherein the spring energy store (4) comprises a spiral spring (29).

3. Boom system (100) according to claim 2, wherein the spiral spring (29), in the furled state of the boom (2), is arranged radially inside the furled boom (2).

4. Boom system (100) according to claim 3, further comprising an empty reel (6, 32, 36, 38, 40, 48), wherein the boom (2) is furled onto the empty reel in the furled state, wherein the spiral spring is arranged radially or / and axially inside the empty reel.

5. Boom system (100) according to claim 4, further comprising a bearing pin (30) which is fixed against rotation at least during unfurling of the boom (2), wherein a radially inner end portion (29b) of the spiral spring (29) is fixed to the bearing pin (30).

6. Boom system (100) according to claim 5, wherein, in the furled state of the boom (2), the spiral spring (29) and the furled boom (2) run substantially around the same axis, wherein the bearing pin (30) runs in the direction of the axis.

7. Boom system (100) according to claim 5 or 6, wherein the bearing pin is fastened to a mounting plate (22) so as to be releasable in the axial direction, so that, before mounting on the mounting plate (22), the spiral spring (29) can be wound by rotation of the bearing pin.

8. Boom system (100) according to any one of claims 2 to 7, wherein the boom (2) in the furled state forms a spiral running in the opposite direction to the spiral spring (29).

9. Boom system (100) according to any one of claims 1 to 8, wherein the boom (2) is designed as a bistable element.

10. Boom system (100) according to any one of claims 1 to 9, further comprising: electrical cabling (50) which extends from a first longitudinal end of the boom (2) to a second longitudinal end of the boom (2), wherein the digital camera (28) is electrically connected to the electrical cabling (50).

11. Boom system (100) according to claim 10, wherein the electrical cabling (50) comprises one or more flexible ribbon cables.

12. Boom system (100) according to any one of claims 1 to 11, wherein, in the unfurled state of the boom (2), the viewing axis (52) is parallel to an unfurled part of the boom (2).

13. Boom system (100) according to any one of claims 1 to 11, wherein the viewing axis (52) is tilted at an acute angle relative to the unfurled part of the boom (2).

14. Satellite (500) comprising the boom system (100) according to any one of claims 1 to 13.

15. Satellite (500) according to claim 14, further comprising: a satellite main body (502) in which the boom system (100) is arranged, wherein the boom (2) in the unfurled state extends away from the satellite main body (502), wherein the digital camera (28) is adapted and fastened to the boom (2) in such a manner that it is able to record an image in which the satellite main body (502) is contained at least in part.