Impact Propulsion System

Abstract

The present invention relates to a propulsion system comprising a motor with a pair of parallel longitudinal tubes (100), each longitudinal tube having a first end (10) and a second end (11) and defining a fluid-filled interior volume (12). Each longitudinal tube (100) has: - a projectile (200) configured for longitudinal movement within the internal volume and fixedly secured to a thruster (201); - a mechanism for launching a projectile from a first end within the internal volume (12), the thruster (201) being arranged to convert the translational motion of the projectile (200) into a rotational motion; - a device arranged at the second end for slowing the rotation of the projectile (200) within the internal volume (12); - a device for returning the projectile (200) towards the first end; -Heat dissipation equipment and and the pushers of the longitudinal tubes rotate in opposite directions to each other.

Description

[Technical field]

[0001] The present invention relates to propulsion systems, and more particularly to impact propulsion systems.

[0002] In particular, the invention is intended for use in the space field, for equipping spacecraft such as satellites. [Background technology]

[0003] To date, space propulsion is based on the principle of action and reaction. Schematically, the principle of action and reaction is reflected by the conservation of momentum in an isolated system in terms of propulsion. Typically, when gas is exhausted from a spacecraft with a given momentum, a momentum with the same absolute value and opposite direction to that of the gas is transferred to the spacecraft. In such a case, momentum must be expelled from the spacecraft, so that it is necessary to consume material to move forward. The efficiency of a propulsion system is measured by a quantity called the specific impulse in seconds. However, this quantity does not tell the whole story. In fact, currently, it takes 8 days to place a 6-ton communication satellite from a geostationary transfer orbit (also called a "GTO" orbit) to a geostationary orbit (also called a "GEO" orbit) using chemical propulsion with a specific impulse of the motor lasting 320 seconds, and 3 tons of fuel are loaded on board the satellite. Using electric propulsion with a motor specific impulse of 1,500 s, it would take eight months, but would require only 400 kg of fuel (typically xenon) and the satellite's mass would be less than four tonnes.

[0004] In other words, current electric propulsion systems have high specific impulse but low thrust, resulting in much longer mission times and lower launch costs since the mass of fuel for a given mission is much smaller than with chemical propulsion systems.

[0005] Moreover, once the satellites are in place, whatever their location, their orbits will be flat, and a change of plane would consume too much fuel and cannot currently be considered.

[0006] On the other hand, satellites in polar orbits and therefore moving generally have a useful life of five years, which corresponds to the time required to consume the fuel on board.

[0007] Finally, as the amount of space debris becomes more abundant, the number of avoidance maneuvers will increase and, as a result, the useful life of satellites in low earth orbit may be reduced. Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention aims to overcome the aforementioned drawbacks. [Means for solving the problem]

[0009] To this end, the present invention provides a propulsion system including a motor having a pair of parallel longitudinal tubes, each longitudinal tube having a first end and a second end and defining a fluid-filled interior volume. a projectile configured for longitudinal movement within the internal volume, the projectile being rigidly secured to the thruster; - a mechanism for launching a projectile from a first end of said longitudinal tube within an internal volume, the thruster being arranged to convert translational motion of the projectile into rotational motion; - a device for braking the rotation of the projectile within the internal volume, the device being positioned at the second end of the longitudinal tube; - a device for returning the projectile from the second end of the longitudinal tube towards the first end; -Heat dissipation equipment and Equipped with.

[0010] The mechanism for launching a projectile and the device for returning a projectile are powered by at least one power source.

[0011] Each longitudinal tube carries within its interior volume a projectile and a thruster rigidly secured to the projectile.

[0012] By "rigidly secured" it is understood that there are no degrees of freedom between the projectile and the thruster.

[0013] The thrusters of the projectiles, located in the two longitudinal tubes, rotate in opposite directions to each other, thus creating two equal but opposite moments of motion as the thrusters rotate, which essentially cancel each other out.

[0014] Such a propulsion system is an impulse thrust propulsion system. Each time a projectile is fired within the longitudinal tube of the projectile by the firing mechanism, it imparts momentum to the projectile towards the second end of the longitudinal tube. According to the action-reaction principle described above, during impact, it imparts momentum in the opposite direction to the longitudinal tube and thus to the propulsion system.

[0015] Advantageously, the propulsion system according to the invention allows a partial conversion of the translational motion of the projectile into a rotational motion thanks to the viscosity of the fluid, one part of which is converted into heat due to the viscosity of the fluid, and another part into thermal or electrical energy depending on the nature of the braking device, thus the part converted into rotation does not interfere with the balance of the total longitudinal momentum of the system.

[0016] At a given time, the projectile has a non-zero translational velocity towards the second end. Thus, the projectile encounters fluid molecules, which convert a part of the translational energy into rotational energy of the projectile. At the end of the journey, at the second end of the longitudinal tube, the projectile may no longer have a translational velocity, but it does have a rotational velocity. If the principle of conservation of momentum is applied, the moment of motion must also be conserved. Nevertheless, it is the fluid contained within the internal volume of the longitudinal tube that sets in motion the thruster and the projectile, and not the longitudinal tube itself. Thus, we obtain a system that conserves translational momentum, i.e. is non-moving, but with a non-zero angular momentum. Thus, the principle of conservation of momentum in an isolated system does not apply in this case, since the system is not isolated.

[0017] In addition, in each longitudinal tube, the heat generated during the movement of the projectile within its internal volume is removed by means of a heat dissipation device, thus proving that the propulsion system does not function as an isolated system.

[0018] The longitudinal tubes (volume, length), the mass of the projectile, and the impulse delivered to the projectile are sized such that the translational motion of the projectile within each longitudinal tube is stopped at the second end of the longitudinal tube.

[0019] Advantageously, the device for returning the projectile enables the projectile to be returned from the second end towards the first end of the longitudinal tube for re-firing.

[0020] Advantageously, the propulsion system according to the invention is a completely passive dissipative reaction mass propulsion system, in which each projectile and its thruster play the role of a reaction mass and are arranged to move freely and passively within the internal volume of the longitudinal tube in which they are arranged, the thrusters being arranged to convert the translational motion of the projectile into a rotational motion through a passive and dissipative interaction with a fluid contained within the internal volume of the longitudinal tube containing said thrusters.

[0021] In particular embodiments, the invention satisfies the following characteristics, which are implemented separately or in each of the technically operable combinations of the following characteristics:

[0022] In certain embodiments of the invention, to avoid contact between the projectiles and the longitudinal tubes, each longitudinal tube is provided with a device for retaining the projectile within its internal volume.

[0023] In certain embodiments of the invention, the device for holding the projectile comprises at least one connecting arm extending between the projectile and the longitudinal tube.

[0024] In a particular embodiment of the invention, the holding device and the projectile are connected by a pivot connection in order not to impede the rotation of the projectile during its movement within the longitudinal tube.

[0025] In a particular embodiment of the invention, for guiding a projectile, each longitudinal tube comprises a device for guiding a projectile in translation within its internal volume.

[0026] In a particular embodiment of the invention, the device for guiding the projectile in translation cooperates with a device for holding the projectile.

[0027] In certain embodiments of the invention, the same power source is configured to power said mechanism for launching a projectile and said device for returning the projectile in at least one longitudinal tube.

[0028] In a particular embodiment of the invention, the propulsion system comprises a tilting device configured to independently pivot each of the two longitudinal tubes about a parallel corresponding pivot axis, preferably in opposite directions of about 90°, which tilting device is activated only when the projectile reaches the second end of the longitudinal tube, to accelerate the return of the projectile towards the first end of the longitudinal tube by the device for returning the projectile.

[0029] In a particular configuration, in order to increase the thrust of the propulsion system in the same direction, said propulsion system comprises a number of pairs of parallel longitudinal tubes, the pairs being arranged parallel to each other.

[0030] The present invention also relates to a means of transport, in particular a spacecraft, comprising a propulsion system according to at least one of the embodiments of the present invention, which spacecraft has a reduced travel time for a given orbit and no fuel consumption, compared to spacecraft equipped with conventional chemical or electric propulsion systems.

[0031] The invention will be better understood on reading the following description, given purely as a non-limiting example, with reference to the drawings, in which: [Brief description of the drawings]

[0032] [Figure 1] 1 illustrates a propulsion system comprising a motor comprising a pair of longitudinal tubes, according to one embodiment of the present invention. [Diagram 2] 1 illustrates an alternative embodiment of a projectile within a longitudinal tube. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] In these figures, for clarity, the drawings are not drawn to scale in uniform units unless otherwise specified.

[0034] The present invention relates to a propulsion system.

[0035] In general, this propulsion system can be equipped, but is not limited to, any vehicle, in particular a vehicle from the aviation, space, rail, automotive or maritime sectors.

[0036] The invention will be described in the particular context of one of its preferred fields of application, in which the propulsion system is intended to be installed in a spacecraft such as a satellite, although nothing excludes the possibility of locating the propulsion system in any other type of vehicle.

[0037] FIG. 1 illustrates generally a propulsion system according to a preferred embodiment of the present invention.

[0038] The propulsion system comprises a motor 500. The motor comprises at least a pair of longitudinal tubes 100.

[0039] In the remainder of this specification, the propulsion system will be described in the preferred case where the motor comprises a pair of longitudinal tubes as illustrated in FIG.

[0040] Advantageously, the two longitudinal tubes 100 are arranged parallel to one another.

[0041] Preferably, the two longitudinal tubes 100 are similar and independent of each other.

[0042] Each longitudinal tube 100 has two longitudinal ends, a so-called first end 10 and a second end 11. Each longitudinal tube 100 is hermetically closed, sealed or closed at both its longitudinal ends.

[0043] Advantageously, the two longitudinal tubes 100 are positioned in the same direction and their first ends 11 are arranged on the same side.

[0044] In the example of FIG. 1, the first end 11 of the longitudinal tube 100 is located on the left side in FIG.

[0045] Preferably, each longitudinal tube 100 has a circular cross-section, as illustrated in FIG. 1, but may also have any other cross-sectional shape, e.g., square, rectangular, oval, etc., without the invention being so limited.

[0046] Preferably, each longitudinal tube 100 is made from a carbon material.

[0047] Each longitudinal tube 100 defines a hollow interior volume 12 in which the fluid expands.

[0048] Preferably, the fluid is a viscous fluid.

[0049] In a preferred embodiment, the fluid is a gas, such as air.

[0050] In other embodiments, the fluid may be Newtonian or non-Newtonian. It should be recalled that a fluid is so-called Newtonian when it does not modify its behavior under the influence of mechanical stress.

[0051] In other embodiments, the fluid may be a fluid whose viscosity changes under the action of a magnetic or electric field, so-called MR (magnetorheological) or ER (electrorheological) fluids, respectively.

[0052] Each longitudinal tube 100 comprises within its interior volume 12 a projectile 200 that is intended and configured to move longitudinally within the longitudinal tube 100.

[0053] Preferably, the projectiles 200 in each longitudinal tube 100 are identical.

[0054] In a first variant, as illustrated in Fig. 1, each projectile 200 takes the form of, for example, a closed, hollow or solid cylinder. For example, each projectile 200 may have a cross-section that is circular, square, rectangular, elliptical, etc., without limiting the invention in this way. The projectile has a length that is much shorter than the length of the longitudinal tube.

[0055] In one embodiment, as illustrated in FIG. 1, the longitudinal tube 100 and its projectile 200 have the same cross-section.

[0056] In a second variant of the projectile, as illustrated in Figure 2, when the longitudinal tube 100 has a circular cross section, each projectile 200 may take the form of an annular hollow cylinder with open ends and whose walls are located close to the inner surface 13 of the longitudinal tube 100. In this way, the mass of the projectiles 100 is distributed near the periphery of the longitudinal tube 100.

[0057] Advantageously, each projectile 200 is rigidly fixed to a thruster 201 .

[0058] By rigidly fixed, it should be understood that there are no degrees of freedom between the projectile 200 and the thruster 201. In other words, when the thruster 201 rotates, it causes the projectile to rotate. When the thruster 201 rotates on its own, it causes the projectile to rotate on its own.

[0059] It should be understood that the projectile 200 and its propellers 201 are both arranged in the interior volume 12 of the longitudinal tube. There are therefore as many propellers and projectiles as there are longitudinal tubes.

[0060] Each projectile 200 and its thruster 201 are arranged in the longitudinal tube 100 such that the thruster's rotation axis 202, and thus the projectile's rotation axis, is parallel to or coincides with the pivot axis 14 of the longitudinal tube 100. Preferably, the thruster's rotation axis 202 coincides with the pivot axis 14 of the longitudinal tube 100, as illustrated in FIG.

[0061] In one embodiment, in the projectile according to the first variant, as illustrated in FIG. 1, the thrusters 201 of the projectile 200 are located on the same side and at one end of the projectile within each corresponding longitudinal tube 100 of the projectile 200.

[0062] Preferably, in each longitudinal tube 100, as illustrated in FIG. 1, the projectile 200 faces a first end 10 of the longitudinal tube 100 and the thruster 201 faces a second end 11 of the longitudinal tube 100.

[0063] In another embodiment, in a projectile according to a second variant, as illustrated in Fig. 2, the thruster 201 of the projectile is located inside the cylinder forming the projectile, in the corresponding longitudinal tube 100 of the projectile. The projectile 100 therefore does not disturb the flow much.

[0064] Advantageously, the thrusters 201 of the projectile 200 located in the longitudinal tubes 100 of a pair of longitudinal tubes counter-rotate with respect to each other, i.e. rotate in opposite directions. Thus, when the thrusters 201 rotate, two identical but opposite momentums are simultaneously generated, the sum of which is approximately zero. Thus, a spacecraft equipped with a propulsion system with an even number of longitudinal tubes 100 and the thruster configuration as described will not become unbalanced during propulsion.

[0065] The efficiency of the thruster 201, i.e., its ability to convert the translational motion of the projectile 200 into rotational motion, depends in particular on the fluid contained in the longitudinal tube and on the pressure within the internal volume of said longitudinal tube.

[0066] In a non-limiting embodiment of the present invention, the propeller 201 may be an aircraft propeller type, an aircraft turbojet engine low pressure compressor propeller type, a centrifugal compressor propeller type, and so on.

[0067] In an improved embodiment, the propeller is a variable pitch propeller. Preferably, the electronic or mechanical device is configured to adjust the pitch, in particular by modifying the pitch angle of the propeller blades.

[0068] Preferably, each longitudinal tube 100 comprises a device 300 for holding a projectile in the internal volume 12 of said longitudinal tube. Advantageously, such a holding device 300 makes it possible to maintain the positioning of the projectile 200 at a distance from the inner surface 13 of the longitudinal tube 100, so that the projectile 200 and / or its propeller 201 come into contact with said inner surface during rotation of the motor.

[0069] Preferably, the device 300 for holding projectiles is identical in both tubes of the pair of longitudinal tubes 100 .

[0070] In an embodiment of the holding device 300, the holding device comprises at least one connecting arm 301, preferably a plurality of connecting arms 301. Each connecting arm 301 is rigid and extends between the projectile 200 and the longitudinal tube 100. Each connecting arm 301 comprises a first end 302 located on the side of the projectile 200 and a second end 303 located on the side of the longitudinal tube 100.

[0071] Preferably, when the device for holding 300 comprises several connecting arms 301, these several connecting arms 301 are arranged in the same plane.

[0072] 1, the device for holding 300 comprises three connecting arms 301 arranged at 120° to each other. Such a number and arrangement of connecting arms is particularly suitable when the longitudinal tube has, for example, a circular cross section.

[0073] In another embodiment, not shown, the holding device comprises four connecting arms arranged at 90° to one another, such a number and arrangement of connecting arms being particularly suitable when the longitudinal tube has, for example, a square or rectangular cross section.

[0074] Preferably, the device for holding 300 is connected to the projectile 200 in such a way that it does not impede the rotation of the projectile 200 about its axis of rotation. In other words, the device for holding and the projectile are connected by a connection with a single degree of freedom. This single degree of freedom is a rotational degree of freedom, allowing the rotation of the projectile about its axis of rotation. The connection is a pivotal connection.

[0075] In one embodiment, the device for holding is connected to the projectile via at least one bearing (not shown).

[0076] In one embodiment, when the device for holding 300 comprises multiple connecting arms 301 arranged in the same plane, the first ends 302 of the connecting arms are connected to the projectile 200 via a single bearing.

[0077] Preferably, each longitudinal tube 100 comprises a device 400 for guiding a projectile in translation. Advantageously, such a device 400 for guiding in translation makes it possible to ensure the longitudinal movement of the projectile 200 in the longitudinal tube 100 between the two longitudinal ends 10 and 11. Advantageously, said device 400 for guiding in translation cooperates with a device 300 for holding the projectile.

[0078] Preferably, the device 400 for guiding in translation is identical for both tubes of the pair of longitudinal tubes 100 .

[0079] In an embodiment of the device 400 for guiding in a translational state, as illustrated in the figure, the device 400 for guiding in a translational state comprises at least one longitudinal groove 401 formed in the longitudinal tube 100 in the area of ​​the inner surface 13.

[0080] Preferably, the longitudinal tube 100 includes as many longitudinal grooves 401 as there are connecting arms 301. The second end 303 of each arm 301 is configured to slide, glide or roll within a corresponding longitudinal groove 401.

[0081] Each longitudinal tube 100 includes a mechanism for launching a projectile (not shown) configured to apply thrust to the projectile 200 to initiate the projectile and launch it through the longitudinal tube 100.

[0082] Preferably, the mechanism for launching the projectile is arranged at the first end 10 of the longitudinal tube 100. Thus, the projectile 200 moves within the longitudinal tube 100 from the first end 10 towards the second end 20.

[0083] Preferably, the mechanism for launching the projectiles is identical for both tubes of the pair of longitudinal tubes 100.

[0084] In one embodiment, the mechanism for launching the projectile may include an electromagnet.

[0085] In another embodiment, the mechanism for launching the projectile may comprise a mechanical system of the catapult or compression spring type.

[0086] In embodiments where the mechanism for launching the projectile is a compression spring, the projectile is launched within the longitudinal tube by the expansion of the compression spring, which has been previously compressed.

[0087] Preferably, at least one power source (not shown) is configured to activate mechanisms for launching projectiles in each longitudinal tube 100. Advantageously, the at least one power source is connected to solar panels mounted on the spacecraft or to batteries on board the spacecraft.

[0088] Thus, at each longitudinal tube 100, the mechanism for launching the projectile is advantageously configured to apply an initial impulse to the projectile 100 at a predefined speed. A momentum or kinetic energy towards the second end 11 of the longitudinal tube 100 is then applied to said projectile. When this impulse is applied, an equal momentum is applied to the longitudinal tube 100 in the opposite direction. During the advancement of the projectile 200 in the longitudinal tube 100, the blades of the propeller 201 are subjected to a resistance that brakes the projectile 200 and a lifting force that drives the propeller 201, so that the projectile 200 is in a state of rotation. Thanks to the propeller 201, the translational motion of the projectile 200 in the longitudinal tube 100 is thus gradually converted into a rotational motion. This rotational motion of the projectile 200 gradually brakes the translational motion of the projectile 200 in the longitudinal tube 100 while generating heat.

[0089] Each blade of the propeller 201 has form resistance and friction resistance. Friction resistance, which is related to the viscosity of the fluid, allows for motion that follows well-known laws of fluid mechanics. In certain embodiments, the propeller blades are designed to maximize friction resistance. It is this friction that generates heat that is released to the outside, making the system non-isolated and therefore the total momentum non-conserved.

[0090] In embodiments where the thruster is a variable pitch thruster, a corresponding electronic or mechanical device is configured to adjust the pitch during movement of the projectile within the longitudinal tube, allowing friction to be maximized.

[0091] In other words, in each longitudinal tube 100, the initial translational kinetic energy of the projectile 200 is partially converted into rotational kinetic energy on the one hand and into heat on the other hand. At the end of the process of the projectile's movement through the longitudinal tubes, it is this "naturally" generated portion of rotational kinetic energy that is in effect obtained as the equivalent of the momentum transferred to the spacecraft.

[0092] The longitudinal tube 100 is sized to a predetermined length such that the translational motion of the projectile 200 stops proximate to, and closest to, the second end 11 of the longitudinal tube 100 without the projectile 200 or the thruster 201 of the projectile 200 contacting the second end 11.

[0093] In particular, the length of the longitudinal tube 100 depends on the mass of the projectile, on the impulse applied to the projectile 200 by the mechanism for launching the projectile, on the efficiency of the thruster in the fluid environment in which the projectile is moving, and on the viscosity of the fluid, which may depend on parameters such as temperature, and on externally regulated parameters such as electromagnetic, electric, or magnetic fields, which also depend on the nature of the fluid. Calculating this length is within the understanding of one skilled in the art.

[0094] In one embodiment, each longitudinal tube has a length in the range of 4 m, a diameter in the range of 50 cm, the mass of the projectile is in the range of 1 kilogram, and the launch velocity of the projectile is in the range of 400 km / hour to 500 km / hour.

[0095] As already mentioned, for each longitudinal tube 100, following an impact applied to the projectile 200, heat is generated within said longitudinal tube during the projectile's movement due to fluid friction.

[0096] Advantageously, each longitudinal tube 100 is equipped with a heat dissipation device (not shown).

[0097] Preferably, the heat dissipation devices are identical for both tubes of the pair of longitudinal tubes 100 .

[0098] In one embodiment, the heat dissipation device is a fin-type heat sink.

[0099] In a preferred application of the propulsion system on a spacecraft, for each longitudinal tube 100, the corresponding heat dissipation device can exchange with empty space exclusively via blackbody radiation. The heat dissipation device is therefore advantageously configured to emit photons, these photons having momentum.

[0100] Advantageously, the heat dissipation devices of each longitudinal tube 100 are arranged such that the photon emission is in a direction that promotes an increase in the momentum of the propulsion system and therefore of the spacecraft.

[0101] Advantageously, this photon emission ensures that the propulsion system cannot be considered as an isolated system.

[0102] As already described, after firing the projectile 200 per longitudinal tube 100, the translational movement of the projectile 200 stops at the second end 11 of the longitudinal tube 100. At this second end 11, the projectile 200 is only rotating and rotates on itself at a given speed.

[0103] Advantageously, each longitudinal tube 100 is equipped with a device (not shown) for braking the rotation of the projectile.

[0104] Preferably, the device for braking is identical for both tubes of a pair of longitudinal tubes 100 .

[0105] In some embodiments, the device for braking comprises an electromagnetic brake or a mechanical brake.

[0106] Braking the rotation of the projectile in each longitudinal tube creates a parasitic torque in the opposite direction. Nevertheless, a motor in a propulsion system comprising a pair of longitudinal tubes inside which a projectile with thrusters rotates in a counter-rotating and braking manner as a first approximation does not lead to any consequences in the propulsion system and therefore in the spacecraft, since the torques practically cancel each other.

[0107] As already described, after firing the projectile 200 for each longitudinal tube 100, the translational movement of the projectile 200 stops at the second end 11 of the longitudinal tube 100 and then the rotation of the projectile 200 is braked.

[0108] Advantageously, each longitudinal tube 100 is provided with a device (not shown in FIG. 1) for returning a projectile towards the first end 10 of said longitudinal tube 100 .

[0109] Preferably, the equipment for returning the projectiles is identical for the two tubes of a pair of longitudinal tubes 100 .

[0110] This device for returning the projectile is configured to return the projectile 200 located at the second end 11 of the longitudinal tube 100 to the first end 10 for re-firing if necessary via the mechanism for firing the projectile.

[0111] Preferably, the device for returning the projectile is configured to return the projectile 200 in the transverse tube at a constant velocity that is slower than the launch velocity of the projectile. Advantageously, returning the projectile 200 towards the first end 10 at a constant velocity can result in the propulsion system, and therefore the spacecraft, generating virtually no parasitic momentum.

[0112] In some embodiments, the device for returning the projectile may comprise an electromagnet, or a worm gear device.

[0113] In one variant, the propulsion system may comprise a tilting device (not shown in FIG. 1 ) to accelerate the return of the projectiles 200 towards the first end 10 of the longitudinal tubes 100. Such a tilting device is configured to independently pivot each of the two longitudinal tubes 100 around a parallel corresponding pivot axis at an angle within the range of 90°, but in the opposite direction. The projectiles 200 of each longitudinal tube 100 are then returned towards the first end 10 of the corresponding longitudinal tube 100, thus in the opposite direction, by means of the corresponding return device described herein above. The return of each projectile 200 towards the first end 10 of the corresponding longitudinal tube 100 can be made more rapid, since on the one hand the generated momentum cancels out, and on the other hand the generated momentum is not parasitic on the momentum applied to the projectile at the pivot axis of the longitudinal tube during the impact, and therefore on the opposite momentum transferred to the longitudinal tube during the impact and consequently to the propulsion system.

[0114] Preferably, at least one power source (not shown) is configured to activate a mechanism for returning projectiles within each longitudinal tube 100 .

[0115] The at least one power source is connected to solar panels mounted on the spacecraft or to a battery on board the spacecraft.

[0116] In one embodiment, the common power source is configured to activate the mechanism for launching the projectile and to activate the device for returning the projectile down the longitudinal tube.

[0117] Thus, as described, the propulsion system according to the present invention is an impulse thrust propulsion system rather than a continuous thrust propulsion system.

[0118] Each time a projectile 200 is fired through the two longitudinal tubes 100, an equal but opposite momentum is imparted to the longitudinal tubes, and therefore to the propulsion system.

[0119] Preferably, the launch of the projectiles 200 in the two longitudinal tubes is performed synchronously to avoid imbalance of the spacecraft.

[0120] The dependence on the frequency of impacts, i.e. the firing frequency of the projectiles 200 in each longitudinal tube 100, depends on the average thrust per unit time of the propulsion system.

[0121] In particular, the frequency of impact depends on the time the projectile 200 spends in each longitudinal tube 100, i.e., the type of return device selected to return the projectile 200 from the second end 11 to the first end 10 of the longitudinal tube 100 using the return device.

[0122] In the same direction, the thrust of the propulsion system can also be increased by increasing the number of pairs of longitudinal tubes 100, each pair arranged parallel to one another and all longitudinal tubes in the same direction.

[0123] In a particular embodiment not shown, in particular to improve the efficiency of the propeller 201, each longitudinal tube 100 may be provided with a device for modifying the viscosity of the fluid, and / or a device for modifying the temperature of the fluid, and / or a device for modifying the pressure of the fluid.

[0124] In one embodiment, to create thrust in all directions, at least one pair of longitudinal tubes are mounted on a multi-axis system configured to orient the at least one pair of longitudinal tubes in a direction opposite the desired thrust direction.

[0125] In some embodiments, since the apparatus for braking the rotation of the projectile 200 within the longitudinal tube creates a parasitic momentum, a spacecraft including a propulsion system may include inertia wheels configured to generate momentum within the spacecraft intended to balance the spacecraft.

[0126] For a propulsion system with a given number of pairs of longitudinal tubes arranged parallel to one another, the propulsion system can then be configured in two ways: a) all projectiles 200 of all pairs of longitudinal tubes 100 are fired synchronously, in which case the thrust is multiplied. In particular, the frequency of impacts depends on the time taken by the projectile to move in each longitudinal tube from the first end of the longitudinal tube to the second end of the longitudinal tube and to return from the second end of the longitudinal tube to the first end using the return device; b) Or the projectiles 200 of each pair of longitudinal tubes 100 are fired sequentially, in which case the thrust is less than if all projectiles of all pairs of longitudinal tubes are fired synchronously, but the frequency of impacts is increased.

[0127] The configuration selected may depend on the vehicle using the propulsion system and, in particular, the operations the vehicle will be performing.

[0128] When using a propulsion system in a preferred application in the space field, a spacecraft equipped with such a propulsion system can use a high thrust configuration (configuration a)) for some operations, e.g. orbital operations, and a smaller but more frequent thrust configuration (configuration b)) for other operations, e.g. operations in "distributed" environments (planets with atmospheres seeking to facilitate aerocapture, gravitational acceleration in the vicinity of asymmetric planets, etc.).

Claims

1. A propulsion system comprising a motor having a pair of parallel longitudinal tubes (100), each of said longitudinal tubes (100) having a first end (10) and a second end (11) and defining a fluid-filled interior volume (12); - a projectile (200) configured to move longitudinally within said internal volume (12), said projectile (200) being rigidly fixed to a thruster (201) without any degrees of freedom between said projectile and said thruster; a mechanism for launching said projectile from said first end (10) of said longitudinal tube (100) within said internal volume (12), said thruster (201) being arranged to convert the translational movement of said projectile (200) into a rotational movement; - a device positioned at the second end (11) of the longitudinal tube (100) for braking the rotational movement of the projectile (200) within the internal volume (12); - a device for moving said projectile (200) back from said second end (11) of said longitudinal tube towards said first end (10); - Heat dissipation devices and Equipped with said mechanism for launching said projectile (200) and said device for returning said projectile (200) are powered by at least one power source; A propulsion system in which the thrusters (201) of the projectiles located in the two longitudinal tubes (100) rotate in counter-rotating directions.

2. 2. The propulsion system of claim 1, wherein each of the longitudinal tubes (100) comprises a device (300) for retaining the projectile within the internal volume (12).

3. 3. A propulsion system according to claim 2, wherein the device (300) for holding the projectile comprises at least one connecting arm (301) extending between the projectile (200) and the longitudinal tube (100).

4. A propulsion system according to claim 2 or 3, wherein the device for holding (300) and the projectile (200) are connected by a pivot connection.

5. A propulsion system according to any one of claims 1 to 4, wherein each of said longitudinal tubes (100) comprises a device (400) for guiding said projectile in translation within said internal volume (12).

6. A propulsion system according to claim 5 and any one of claims 2 to 4, wherein the device (400) for guiding the projectile (200) in translation cooperates with the device (300) for holding the projectile.

7. A propulsion system according to any one of claims 1 to 6, wherein the same power source is configured to power the mechanism for launching the projectile (200) and the device for returning the projectile (200) of at least one of the longitudinal tubes (100).

8. A propulsion system according to any one of claims 1 to 7, comprising a tilting device configured to independently pivot each of the two longitudinal tubes (100) about parallel corresponding pivot axes.

9. A propulsion system according to any one of the preceding claims, comprising a plurality of pairs of parallel longitudinal tubes (100), said pairs being arranged parallel to one another.

10. A spacecraft comprising a propulsion system according to any one of claims 1 to 9.

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