Spacecraft, propulsion device and method for propelling a spacecraft by means of laser ablation

Abstract

Spacecraft (200) with a propulsion device (100) comprising at least a propulsion module (10) with at least one laser system (12) for emitting a laser beam (50), a scanning device (40) for receiving and directing the laser beam (50) to an area (60) of the spacecraft (200) which is designed or provided as a material source for removing material from the spacecraft (200) by the laser beam (50).

Description

State of the art

[0001] The invention relates to a spacecraft with a propulsion device, a propulsion device for a spacecraft and a method for propelling a spacecraft with a propulsion device by means of laser ablation.

[0002] A variety of propulsion systems are known for generating thrust on spacecraft. Currently, chemical propulsion, cold gas propulsion, electric propulsion, ion propulsion, Hall-effect propulsion, field-effect propulsion (ion propulsion), and light sails are used. Research projects are also investigating laser propulsion, electric propulsion, plasma propulsion, and pulsed plasma thrusters (PPTs) as spacecraft propulsion systems.

[0003] Many of the existing technologies require a fuel tank and fuel to provide thrust.

[0004] For physical reasons, chemical propulsion systems achieve a maximum specific impulse of approximately 450 s, which requires a relatively large amount of fuel compared to, for example, electric propulsion systems. The specific impulse I sp in seconds is the change in momentum in N s per ejected propellant mass in kg divided by the acceleration due to gravity in m / s 2 . Specific impulse can be considered as fuel efficiency.

[0005] Chemical propulsion also has a limited thrust range in which it can be used, limiting the accuracy of thrust control. Today's exclusively chemical propulsion systems allow for controlled re-entry of the spacecraft, for example, for a crash into the ocean, which may be necessary for large spacecraft if there is a significant risk that the object will not burn up completely upon re-entry into the atmosphere.

[0006] Cold gas engines achieve a low specific impulse of typically 80 s, which requires a lot of fuel to power a spacecraft.

[0007] Ion drives, Hall effect drives, field effect drives, and plasma drives require high voltages, magnetic fields, high-frequency fields, and fuel tanks for liquid or gaseous propellants.

[0008] Light sails only function in sunlight and not in the Earth's shadow, are complicated to set up and have low thrust and poor thrust vector control.

[0009] Classic laser propulsion requires multiple systems to enable thrust vector control.

[0010] In PPT drives, their electrodes degrade extremely quickly and are therefore not durable enough for practical use.

[0011] WO 2022 / 089979 describes a method for planning a satellite maneuver, in particular for planning a change in a satellite's orbit after the completion of a mission, wherein the satellite has a propulsion unit with a ground-based power supply. The method comprises the steps of configuring at least one ground-based laser system for generating a laser beam, in particular laser pulses; configuring at least one laser ground station including the at least one laser system; and laying out an optical transmission link for transmitting the laser pulses from the at least one ground station to the satellite.

[0012] The method further comprises the steps of configuring the satellite-based propulsion unit, in particular an ablation propulsion unit, in which mass is removed from the propulsion unit using laser pulses; and determining a trajectory curve achievable by the propulsion unit. These steps are repeated iteratively until the desired trajectory change is achieved. Disclosure of the invention

[0013] The object of the invention is to provide an improved spacecraft with a propulsion device.

[0014] Another object of the invention is to provide an improved propulsion device for a spacecraft.

[0015] A further object of the invention is to provide an improved method for propelling a spacecraft with a propulsion device.

[0016] The objects are achieved by the features of the independent claims. Advantageous embodiments and advantages of the invention emerge from the further claims, the description, and the drawings.

[0017] According to one aspect of the invention, a spacecraft is proposed with a drive device which at least comprises a drive module with at least one laser system for emitting a laser beam, and a device, in particular a scanning device, for receiving and directing the laser beam to an area, in particular on an outer side, of the spacecraft, which area is designed or provided as a material source for removing material from the spacecraft by the laser beam.

[0018] At least the device can be arranged outside a thermally insulated central volume (if present) of the spacecraft.

[0019] The proposed spacecraft features laser-ablative propulsion, allowing the use of solid propellant, eliminating the need for a propellant tank. This is an advantage over all propulsion technologies that require liquid or gaseous propellants. These include, for example, cold gas propulsion, chemical propulsion (except solid propulsion), and ion engines.

[0020] In addition, laser-ablative propulsion systems can demonstrably achieve a high specific impulse, greater than 1000 s, and thus require relatively little fuel or mass.

[0021] Laser-ablative propulsion typically does not require (besides laser radiation) additional electromagnetic fields, as is the case with most electric propulsion systems, i.e. high voltage, strong magnetic field, RF frequencies, which must be shielded to avoid interfering with the rest of the spacecraft's electronics.

[0022] Laser-ablative drives can be operated electrically and are therefore not directly dependent on solar radiation, for example, as is the case for light sails, thanks to energy storage.

[0023] Laser-ablative propulsion enables very fine thrust adjustment due to the extremely low pulse bits (nN s) that can be selected and the almost continuously variable laser pulse repetition rate. By transferring the facility's laser scanning system outside the spacecraft, the well-known properties of laser-ablative propulsion can be further improved: The proposed propulsion system is capable of addressing multiple areas of the spacecraft as propellant reservoirs (exposed solids) with a laser system, thus allowing the implementation of very effective thrust vector control.

[0024] Because one propulsion unit can already address multiple propellant reservoirs, adding a second propulsion unit can easily achieve redundancy for the entire thrust generation system. This means that one propulsion unit could fail completely without jeopardizing the mission. In this case, the maximum thrust is simply reduced by half. The total addressable impulse and attitude control remain virtually unaffected.

[0025] The simultaneous operation of two propulsion systems also allows the thrust vector to be placed almost ideally through the center of gravity of the spacecraft, so that it does not experience any torque during acceleration maneuvers.

[0026] Relocating the facility's laser scanning head outside the spacecraft now allows, in addition to thrust generation, laser radiation and laser-based measurement techniques to be applied to a large portion of the spacecraft's exterior. This allows, for example, laser material processing of the spacecraft's outer skin for separating, cutting, welding, roughening, heat treating, or drilling the surface or components. Optionally, optical components can also be regenerated using processes such as laser sputtering.

[0027] With suitable laser parameters, a slight pressure can be exerted on components as photon pressure.

[0028] Measurement methods such as LIPS (laser induced plasma spectroscopy) for material characterization, LIDAR (Light Detection And Ranging) for surface characterization and polarimetry can be added by adding detectors to the drive device.

[0029] In addition to dedicated propellant mass in the form of an ablator, the laser system can also separate support mass that was required by mission parameters such as the rocket launch with its acceleration, but is no longer relevant for the subsequent course of the mission, or even use it directly as propellant.

[0030] This allows the mass of the spacecraft to be further reduced to save fuel, while simultaneously using the same mass as fuel to further reduce the amount of dedicated fuel required, thus saving further mass.

[0031] After the mission ends, a satellite usually needs to be lowered into a re-entry trajectory. If the satellite contains components that could survive re-entry, a controlled re-entry would be necessary, for example, over ocean areas away from shipping routes. This precise lowering with a comparatively high thrust requirement over a short period of time is not possible with current electric propulsion systems, for example, so a chemical propulsion system with a relatively high fuel and mass must usually be installed.

[0032] In this case, the proposed propulsion system offers the possibility of preparing the spacecraft's robust components for re-entry, for example, through laser material processing—for example, perforating, machining, or cutting them to enable a potentially complete burn-up of the satellite. Demonstrating this functionality may further reduce the requirements for the propulsion system for re-entry, as it would then enable an uncontrolled re-entry that merely requires orbit descent and thus also allows for long thrust phases, for which the proposed propulsion system is also suitable.

[0033] For example, for a laser-ablative drive, so-called off-axis imaging can be advantageously used to irradiate the scanned laser beam at an inclination angle relative to the normal of the ablation zone without the need for refocusing. Such an arrangement can also be used in the drive device proposed here to provide a focal plane that is essentially parallel to the satellite surface and / or the ablation zone.

[0034] Since relatively large distances, typically 0.5 to 4 times the edge length of the spacecraft, are required, and the scanning optics will not be arbitrarily large, the laser focus can advantageously have a relatively large Rayleigh length, i.e., the distance along the optical axis required by a laser beam until its cross-sectional area doubles, starting from the beam waist or focus. Thus, a tilted or even flat focus surface for the laser beam is not required.

[0035] The simplest way to focus the beam onto the ablation surface is to focus it weakly, preferably with a variable focusing unit, and then scan it over the surface of the material to be ablated using one or more, typically one or two, fast deflection mirrors. It may also be useful to combine a fast scanner with a slow aligning mirror to address the largest possible area for ablation.

[0036] Typical parameters for efficient thrust generation with the ablation of aluminum are a pulse energy surface density (fluence) of 3 to 5 J / cm 2at a pulse duration of 5 ns and a wavelength of 1 µm. With a focus diameter of 0.1 mm, this translates into a pulse energy of approximately 0.3 to 0.5 mJ and a Rayleigh length of almost 300 mm. Thus, relatively large focus shifts during the scanning process can be neglected. The divergence angle of the laser beam is approximately 7 mrad, which means that a scanning optics system has an aperture of 7 mm at a distance of 1 m and 14 mm at a distance of 2 m.

[0037] With higher pulse energies, even larger ablation areas can be addressed with smaller optics.

[0038] According to a favorable design of the spacecraft, the device can be mounted on a boom of the spacecraft. In this way, various areas on the outer surface of the spacecraft can be conveniently reached with the laser beam for ablation. A scanning optics of the device can, for example, be mounted on a rod (boom), which cleverly positions it relative to the spacecraft.

[0039] According to a favorable design of the spacecraft, the propulsion module can be mounted on the spacecraft. This allows the propulsion module with the laser system to be economically supplied with energy from the spacecraft and can have a stable and / or protected mounting location on the spacecraft.

[0040] In a favorable spacecraft design, the propulsion module can be mounted on the boom. Alternatively, it is also possible for at least the propulsion module's laser system and the necessary electronics to be mounted on the boom, with only control signals and the power supply being provided by the spacecraft. The propulsion module and the system can advantageously be mounted together on the boom in a compact design.

[0041] The laser system of the drive module can be attached to the end of the boom, but can also send the laser radiation in the form of a laser beam to the scanning device through or alongside the boom.

[0042] According to a favorable design of the spacecraft, the boom can be adjustable at least in its length and / or position relative to the area. In particular, the boom can be designed as at least one of a telescopic device, a pressurizable hose, or a stabilized cable device. The boom can thus enable flexible positioning of the device in order to be able to direct the laser beam in a suitable manner onto the area of ​​the spacecraft for ablating material. Typically, the boom is only extended, unfolded, or positioned with a similar mechanism after launch in space. The term "boom" is not to be understood in a restrictive sense here. For example, a pressurizable hose that was previously flexible, or a clever cable construction that is stabilized by the flight dynamics, e.g., through rotation, can also be used.

[0043] According to a favorable design of the spacecraft, the propulsion module may comprise a beam splitter and a measuring system, wherein the beam splitter may be configured to guide a portion of a returning laser radiation into the measuring system.

[0044] This allows the returning laser beam to be continuously analyzed, allowing the outgoing laser beam to be optimized for thrust generation requirements. By analyzing the laser beam reflected from the area of ​​the spacecraft containing the material to be ablated, mismatching the laser beam with the material in the ablation area can be avoided. In addition, the addressable surface of the spacecraft can optionally be examined, should this be necessary for the mission.

[0045] According to a favorable design of the spacecraft, the drive module can have at least two mirrors for deflecting and / or moving the laser beam for scanning the material source and / or for stabilizing the laser beam relative to the device. Thus, the drive module can assume at least some of the functions of the device, which can facilitate the compact design of the drive device.

[0046] According to a favorable design of the spacecraft, the boom can have relay optics. In particular, the relay optics can comprise a plurality of optical lenses for at least a 4f image of the laser beam. A scanned laser beam can also be guided along the boom using relay optics. The relay optics can shape the laser beam appropriately and transmit it with as little loss as possible.

[0047] According to a favorable embodiment of the spacecraft, the device can comprise at least one mirror and / or deflector for moving the laser beam and / or at least one optical unit for focusing the laser beam on the region of the spacecraft that is designed or intended as a material source. This advantageously provides the possibility of ablating material at the focus of the laser beam.

[0048] According to a favorable embodiment of the spacecraft, the device can have at least two mirrors and / or deflectors, wherein a focusing lens, in particular a variable one, can be arranged between or in front of the at least two mirrors and / or deflectors for focusing the laser beam on the region of the spacecraft which is designed or provided as a material source.

[0049] The mirror and / or deflector arranged downstream of the focusing lens in the beam path can be designed to scan the material source with the laser beam. This can advantageously provide the possibility of ablating material at the focus of the laser beam.

[0050] According to a further aspect of the invention, a propulsion device for a spacecraft is proposed, comprising at least one propulsion module with at least one laser system for emitting a laser beam, and a device, in particular a scanning device, for receiving and directing the laser beam to an area, in particular on an exterior side, of the spacecraft, which is designed or provided as a material source for removing material from the spacecraft by the laser beam. At least the device is arranged outside the spacecraft.

[0051] The proposed propulsion system features laser-ablative propulsion, allowing the use of a solid propellant, eliminating the need for a propellant tank. This is an advantage over all propulsion technologies that require liquid or gaseous propellants. These include, for example, cold gas propulsion, chemical propulsion (except solid propulsion), and ion propulsion.

[0052] In addition, laser-ablative propulsion systems can demonstrably achieve a high specific impulse, greater than 1000 s, and thus require relatively little fuel or mass.

[0053] Laser-ablative propulsion allows for extremely fine thrust adjustment due to the extremely low pulse bits (nN s) that can be selected via the almost continuously variable laser pulse repetition rate. By transferring the facility's laser scanning system outside the spacecraft, the well-known properties of laser-ablative propulsion can be further improved: The proposed propulsion system is capable of using multiple areas of the spacecraft as propellant reservoirs (exposed solids) with a laser system, thus enabling the implementation of very effective thrust vector control.

[0054] Relocating the facility's laser scanning head outside the spacecraft now allows for the placement of laser radiation and laser-based measurement techniques over a large portion of the spacecraft's exterior, in addition to thrust generation. This allows, for example, laser material processing of the spacecraft's outer skin for separating, cutting, welding, roughening, heat treatment, or drilling of the surface or components. Optionally, optical components can also be regenerated, for example, using laser sputtering.

[0055] According to a further aspect of the invention, a method for propelling a spacecraft by means of laser ablation with a propulsion device is proposed, wherein at least one propulsion module of the propulsion device emits a laser beam, and a device receives the laser beam and focuses it on an area of ​​the spacecraft which serves at least temporarily as a material source for ablating material on the spacecraft by the laser beam.

[0056] The material removal can advantageously generate thrust for the spacecraft.

[0057] The proposed process is based on laser-ablative propulsion, allowing the use of a solid propellant, eliminating the need for a propellant tank. This is an advantage over all propulsion technologies that require liquid or gaseous propellants. These include, for example, cold gas propulsion, chemical propulsion (except solid propulsion), and ion thrusters.

[0058] In addition, laser-ablative propulsion systems can demonstrably achieve a high specific impulse, greater than 1000 s, and thus require relatively little fuel or mass.

[0059] Laser-ablative drives enable very fine thrust adjustment due to the extremely low pulse bits (nN s) that can be selected via the almost stepless variation of the laser pulse repetition rate.

[0060] According to a favorable embodiment of the method, the device and / or the propulsion module can be arranged on a boom of the spacecraft, which can be extended or retracted as needed. By transferring the laser scanning system of the device and / or the propulsion module outside the spacecraft, the known properties of laser-ablative propulsion can be further improved.

[0061] The proposed propulsion system is capable of using multiple areas of the spacecraft as propellant reservoirs (exposed solids) with a laser system, thus enabling the implementation of very effective thrust vector control.

[0062] Relocating the facility's laser scanning head outside the spacecraft now allows for the placement of laser radiation and laser-based measurement techniques over a large portion of the spacecraft's exterior, in addition to thrust generation. This allows, for example, laser material processing of the spacecraft's outer skin for separating, cutting, welding, roughening, heat treatment, or drilling of the surface or components. Optionally, optical components can also be regenerated, for example, using laser sputtering.

[0063] In a favorable embodiment of the process, a portion of the laser radiation from the propulsion module can be directed into a measurement system via a beam splitter. This allows the returning laser beam to be continuously analyzed, allowing the outgoing laser beam to be optimized for thrust generation requirements. By analyzing the laser beam reflected from the area of ​​the spacecraft containing the material to be ablated, a mismatch of the laser beam with the material of the ablation area can be avoided. In addition, the addressable surface of the spacecraft can optionally be examined, should this be necessary for the mission.

[0064] According to a favorable embodiment of the method, the laser beam can be deflected and / or moved with at least one, in particular at least two, mirrors of the drive module. This allows the drive module to assume at least some of the functions of the device, which can promote the compact design of the drive device.

[0065] According to a favorable embodiment of the method, the laser beam can be projected onto the device via a relay optics system arranged in the boom, whereby the laser beam can be projected via a plurality of optical lenses of the relay optics using 4f images. The relay optics allows the laser beam to be suitably shaped and transmitted with as little loss as possible.

[0066] According to a favorable embodiment of the method, the laser beam can be moved with at least one mirror and / or deflector of the device and / or focused with at least one optical unit on the area of ​​the spacecraft that can be ablated as a material source. This advantageously provides the possibility of ablating material at the focus of the laser beam.

[0067] According to a favorable embodiment of the method, the laser beam can be focused onto the region of the spacecraft serving as the material source using a focusing lens, in particular a variable one, which is arranged between or in front of the at least two mirrors and / or deflectors. The laser beam can be moved using the mirror and / or deflector arranged downstream of the focusing lens in the beam path. Thus, the mirror and / or deflector arranged downstream of the focusing lens in the beam path can be designed to scan the material source with the laser beam. This advantageously provides the possibility of ablating material at the focus of the laser beam.

[0068] According to a favorable embodiment of the method, to regenerate a window of a laser beam exiting the device, the laser beam can be focused at least temporarily on the window. This allows material deposited on it during ablation to be removed again by the laser beam.

[0069] According to a favorable embodiment of the method, a vacuum-based thin-film production process can be used to regenerate a mirror of the drive device using the laser beam, at least temporarily, whereby the mirror can be coated. Optionally, optical components can also be regenerated, for example, using laser sputtering.

[0070] There are two ways to regenerate the beam exit. It is possible to position a window at the beam exit, which can be regenerated using various methods, including focusing the laser beam on the window or changing the window if material from the ablation becomes deposited on it.

[0071] Alternatively, the deflecting mirrors can be regenerated, for example, by thermal vapor deposition. Any process used to create reflective surfaces in a vacuum is conceivable.

[0072] According to a favorable embodiment of the method, during a spacecraft mission, material can be brought into the area, in particular on the outside of the spacecraft, which serves at least temporarily as a material source for ablating material from the spacecraft using the laser beam. In particular, the material can be of natural or artificial origin. For example, during missions that visit another celestial body, material from this body can be attached to the outside of the spacecraft and used as fuel for the laser ablative propulsion. In this way, the fuel supplies can advantageously be replenished during the spacecraft mission, which can, for example, advantageously extend the mission. The material source can be of either natural origin, i.e. material from the celestial body, or of artificial origin, e.g. material produced on the celestial body.The material can be applied manually or automatically to the outside of the spacecraft in the area. drawing

[0073] Further advantages will become apparent from the following description of the drawings. The drawings illustrate exemplary embodiments of the invention. The drawings, the description, and the claims contain numerous features in combination. Those skilled in the art will also expediently consider the features individually and combine them into useful further combinations.

[0074] Examples include: Fig. 1 is a schematic representation of a spacecraft with a propulsion device according to an embodiment of the invention; Fig. 2 is a schematic representation of a drive module of the propulsion device of the spacecraft for emitting a laser beam according to an embodiment of the invention; Fig. 3 is a schematic representation of a relay optics arranged in a boom of the spacecraft according to an embodiment of the invention; Fig. 4 a schematic representation of a device, in particular a scanning device, for receiving and guiding the laser beam according to an embodiment of the invention; Fig. 5 a schematic representation of a device, in particular a scanning device, for receiving and guiding the laser beam according to a further embodiment of the invention; and Fig. 6 a schematic representation of a spacecraft with a propulsion device according to a further embodiment of the invention. Embodiments of the invention

[0075] In the figures, components of the same type or function similarly are designated by the same reference numerals. The figures are merely examples and are not to be construed as limiting.

[0076] Before describing the invention in detail, it should be noted that it is not limited to the specific components of the device and the specific method steps, as these components and methods may vary. The terms used herein are intended solely to describe particular embodiments and are not intended to be limiting. Furthermore, when the singular or indefinite articles are used in the description or claims, this also refers to the plural of these elements, unless the overall context clearly indicates otherwise.

[0077] The directional terminology used below, including terms such as "left," "right," "top," "bottom," "before," "behind," "after," and the like, is intended solely to enhance understanding of the figures and is in no way intended to limit the scope of the invention. The components and elements depicted, as well as their design and use, may vary according to the considerations of a person skilled in the art and may be adapted to specific applications.

[0078] Fig. 1 shows a schematic representation of a spacecraft 200 with a propulsion device 100 according to an embodiment of the invention.

[0079] The spacecraft 200 comprises a propulsion device 100 with a propulsion module 10 with at least one laser system 12 (see Fig. 2) and with a device 40, in particular a scanning device. The device 40 can be arranged outside a thermally insulated central volume of the spacecraft 200.

[0080] The drive module 10 of the drive device 100 emits a laser beam 50. The device 40 receives the laser beam 50 and focuses it on an area 60 of the spacecraft 200, which serves at least temporarily as a material source for ablating material from the spacecraft 200 by the laser beam 50. The device 40 is arranged outside the spacecraft 200. The material beam 70 with the ablated material is schematically shown pointing away from the spacecraft 200.

[0081] The propulsion module 10 is arranged on the spacecraft 200.

[0082] The device 40 is arranged on a boom 30 of the spacecraft 200, through which the laser beam 50 is guided. Optionally, the boom 30 can have a relay optics 32 as in Fig. 3. The relay optics 32 may, for example, comprise a plurality of optical lenses 34 for at least a 4f- Fig. of the laser beam 50.

[0083] The boom 30 is designed to be adjustable at least in its length and / or position relative to the region 60. In particular, the boom 30 can be, for example, a telescopic device, a pressurizable hose, or a stabilizeable cable device. The boom can be extended or retracted as needed. In particular, the boom can be folded during the launch of the spacecraft and only extended in space.

[0084] In the illustrated embodiment, the spacecraft 200 thus has a laser-ablative propulsion module 10, which is connected to the scanning device 40 via a boom 30. The laser beam 50 is generated in the propulsion module 10 and sent to the scanning device 40 via the boom 30.

[0085] The scanning device 40 serves to focus the laser beam 50 onto the spacecraft 200, thereby ablating material from it. The ablation beam 70 then generates a recoil. To vary the thrust vector, other positions on the spacecraft are also suitable for generating ablative thrust.

[0086] Fig. 2 shows a schematic representation of the drive module 10 of the drive device 100 of the spacecraft 200 for emitting a laser beam 50 according to an embodiment of the invention.

[0087] The drive module 10 has a laser system 12 that generates a laser beam 50. Furthermore, the drive module 10 has two mirrors 18, 20 for deflecting and / or moving the laser beam 50 for scanning the material source and / or for stabilizing the laser beam 50 relative to the device 40. The laser beam 50 is deflected and / or moved using the two mirrors 18, 20 of the drive module 10.

[0088] The propulsion module 10 further includes an optional beam splitter 16 and a measuring system 14. The beam splitter 16 is arranged in the beam path in front of the first mirror 18. This guides the returning laser radiation 52 into a measuring system 14. This allows the returning laser beam 52 to be continuously analyzed, allowing the outgoing laser beam 50 to be optimized for thrust generation requirements. By analyzing the laser beam 52 reflected from the region 60 of the spacecraft 200 containing the material to be ablated, a mismatch of the laser beam 50 to the material of the ablation region can be avoided. Furthermore, the addressable surface of the spacecraft can optionally be examined, should this be necessary for the mission.

[0089] Optionally, a method of vacuum-based thin film production can be used at least temporarily to regenerate a mirror 18, 20 of the drive device 10 by means of the laser beam 50, wherein the mirror 18, 20 is coated.

[0090] In Fig. Figure 3 shows a relay optics system according to an embodiment of the invention, optionally arranged in the boom 30 of the spacecraft. The laser beam 50 is imaged onto the device 40 via the relay optics system 32 arranged in the boom 30. This conventional structure for a relay optics system 32 is based on a series of 4f- Fig. with lenses 34 and can transmit both the laser radiation 50 and its exit angle. This makes it possible to provide a passive scanning optics at the end of the boom 30.

[0091] Fig. 4 shows a schematic representation of a device 40, in particular a scanning device, for receiving and guiding the laser beam 50 according to an embodiment of the invention.

[0092] The device 40 has two mirrors 44, 46 and / or deflectors 44, 46 for moving the laser beam 50 and an optical unit 42 for focusing the laser beam 50 onto the region 60 of the spacecraft 200, which is designed or provided as a material source.

[0093] Optionally, a method of vacuum-based thin film production can be used at least temporarily to regenerate a mirror 44, 46 of the device 40 by means of the laser beam 50, wherein the mirror 44, 46 is coated.

[0094] The device 40 represents an active scanning optics system. The laser beam 50 enters the device 40 and is guided and scanned by one or more mirrors 44, 46 or deflectors 44, 46. Finally, the laser beam 50 is focused by one of the optical units 42, thereby providing the possibility of ablating the material at the focus 54 of the laser beam 50.

[0095] To regenerate a window 43 of a beam exit of the laser beam 50 from the device 40, the laser beam 50 can be focused at least temporarily onto the window 43 in order to remove material deposited thereon by the ablation.

[0096] Fig. 5 shows a schematic representation of a device 40, in particular a scanning device, for receiving and guiding the laser beam 50 according to a further embodiment of the invention.

[0097] The device 40 also has two mirrors 44, 46 and / or deflectors 44, 46. A focusing lens 48, in particular a variable one, is arranged between the mirrors 44, 46 and / or deflectors 44, 46 for focusing the laser beam 50 onto the region 60 of the spacecraft 200, which is designed or intended to be a material source. The mirror and / or deflector 44, 46 arranged downstream of the focusing lens 48 in the beam path is designed for scanning the material source with the laser beam 50.

[0098] The device 40 represents a further embodiment of an active scanning optics system. The laser beam 50 enters the device 40 and is guided and scanned by one or more mirrors 44, 46 or deflectors 44, 46. Before passing the actual scanning mirrors 44, 46, the laser beam 50 is focused by the optionally variable focusing lens 48. This provides the possibility for ablation at the focus 54 of the laser beam 50.

[0099] In Fig. 6 is a schematic representation of a spacecraft 200 with a propulsion device 100 according to a further embodiment of the invention.

[0100] In this further variant, the drive module 10 and also relevant electronics are relocated to the outside, so that the laser system 12, electronics and device 40 on the boom 30 are arranged outside the spacecraft 200 and only control signals and power supply are still provided by the spacecraft 200.

[0101] With the extendable boom 30, a compact module can also be offered in this embodiment, which is installed similarly to a conventional drive of the spacecraft 200, which is only unfolded in space and then provides full functionality. Reference symbol 10 drive module 12 Laser system 14 Measuring system 16 beam splitters 18 mirrors 20 mirrors 30 booms 32 Relay optics 34 lens 36 4f-image 40 Scanning device 42 Optical unit 43 windows 44 mirrors 46 mirrors 48 Focusing lens 50 laser beam 52 returning laser beam 54 Focus of the laser beam 60 area 70 ablation beam 100 drive device 200 spacecraft 202 Outside QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] WO 2022 / 089979

[0011]

Claims

[1] Spacecraft (200) with a propulsion device (100) comprising at least - a drive module (10) with at least one laser system (12) for emitting a laser beam (50), - a device (40), in particular a scanning device, for receiving and directing the laser beam (50) to an area (60), in particular on an outer side (202), of the spacecraft (200), which area is designed or provided as a material source for removing material from the spacecraft (200) by the laser beam (50). [2] A spacecraft according to claim 1, wherein the device (40) is arranged on a boom (30) of the spacecraft (200). [3] Spacecraft according to claim 1 or 2, wherein the propulsion module (10) is arranged on the spacecraft (200). [4] Spacecraft according to claim 2 or 3, wherein the propulsion module (10) is arranged on the boom (30). [5] Spacecraft according to claims 2 to 4, wherein the boom (30) is designed to be adjustable at least in its length and / or position relative to the region (60), in particular wherein the boom (30) is designed at least as one of a telescopic device, a pressurizable hose, a stabilizeable cable device. [6] Spacecraft according to one of the preceding claims, wherein the drive module (10) comprises a beam splitter (16) and a measuring system (14), wherein the beam splitter (16) is designed to guide a portion of a returning laser radiation (52) into the measuring system (14). [7] Spacecraft according to one of the preceding claims, wherein the drive module (10) has at least one, in particular at least two mirrors (18, 20) for deflecting and / or moving the laser beam (50) for scanning the material source and / or for stabilizing the laser beam (50) relative to the device (40). [8] Spacecraft according to one of claims 2 to 7, wherein the boom (30) comprises a relay optics (32), in particular wherein the relay optics (32) comprises a plurality of optical lenses (34) for at least one 4f image (36) of the laser beam (50). [9] Spacecraft according to one of the preceding claims, wherein the device (40) comprises at least one mirror (44, 46) and / or deflector (44, 46) for moving the laser beam (50) and / or at least one optical unit (42) for focusing the laser beam (50) on the region (60) of the spacecraft (200) which is designed or provided as a material source. [10] Spacecraft according to one of the preceding claims, wherein the device (40) has at least two mirrors (44, 46) and / or deflectors (44, 46), wherein a focusing lens (48), in particular a variable focusing lens, is arranged between or in front of the at least two mirrors (44, 46) and / or deflectors (44, 46) for focusing the laser beam (50) onto the region (60) of the spacecraft (200) which is designed or provided as a material source, wherein the mirror and / or deflector (44, 46) arranged downstream of the focusing lens (48) in the beam path is designed for scanning the material source by the laser beam (50). [11] Propulsion device (100) for a spacecraft (200) according to one of the preceding claims, comprising at least - a drive module (10) with at least one laser system (12) for emitting a laser beam (50), - a device (40), in particular a scanning device, for receiving and directing the laser beam (50) to an area (60), in particular on an outer side (202), of the spacecraft (200), which area is designed or provided as a material source for removing material from the spacecraft (200) by the laser beam (50), wherein at least the device (40) is arranged outside the spacecraft (200). [12] Method for propelling a spacecraft (200) by means of laser ablation according to one of claims 1 to 10 with a propulsion device (100) according to claim 11, wherein at least one propulsion module (10) of the propulsion device (100) emits a laser beam (50), and a device (40) receives the laser beam (50) and focuses it on an area (60), in particular on an outer side (202) of the spacecraft (200), which area serves at least temporarily as a material source for ablating material on the spacecraft (200) by the laser beam (50). [13] Method according to claim 12, wherein the device (40) and / or the drive module (10) are arranged on a boom (30) of the spacecraft (200), which is extended or retracted as required. [14] Method according to claim 12 or 13, wherein a part of a returning laser radiation (52) of the drive module (10) is guided into a measuring system (14) via a beam splitter (16). [15] Method according to one of claims 12 to 14, wherein the laser beam (50) is deflected and / or moved with at least one, in particular at least two mirrors (18, 20) of the drive module (10). [16] Method according to one of claims 12 to 15, wherein the laser beam (50) is imaged onto the device (40) via a relay optics (32) arranged in the boom (30), wherein the laser beam (50) is imaged via a plurality of optical lenses (34) of the relay optics (32) by means of 4f images (36). [17] Method according to one of claims 12 to 16, wherein the laser beam (50) is moved with at least one mirror (44, 46) and / or deflector (44, 46) of the device (40) and / or is focused with at least one optical unit (42) onto the region (60) of the spacecraft (200) which is ablated as a material source. [18] Method according to one of claims 12 to 17, wherein the laser beam (50) is focused onto the region (60) of the spacecraft (200) which serves as a material source by means of a, in particular variable, focusing lens (48) which is arranged between or in front of the at least two mirrors (44, 46) and / or deflectors (44, 46), wherein the laser beam (50) is moved by means of the mirror and / or deflector (44, 46) arranged in the beam path after the focusing lens (48). [19] Method according to one of claims 12 to 18, wherein for regenerating a window (43) of a beam exit of the laser beam (50) from the device (40), the laser beam (50) is at least temporarily focused on the window (43). [20] Method according to one of claims 12 to 19, wherein for regenerating a mirror (18, 20, 44, 46) of the drive device (10) and / or the device (40) by means of the laser beam (50), a method of vacuum-based thin film production is used at least temporarily, wherein the mirror (18, 20, 44, 46) is coated. [21] Method according to one of claims 12 to 20, wherein during a mission of the spacecraft (200) material is brought into the region (60), in particular on the outside (202) of the spacecraft (200), which at least temporarily serves as a material source for removing material from the spacecraft (200) by the laser beam (50), in particular wherein the material is of natural or artificial origin.

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