FR3110552A1 - Vehicle in orbit with roll-up and deployable membrane for attitude and orbit control - Google Patents

Abstract

The invention relates to a vehicle (100) in orbit having an instantaneous position and an instantaneous attitude, said vehicle (100) being intended to take a set position and a set attitude in its orbit, comprising: a body (101); N storage rollers (R1, R2) connected to the box (101), N being an integer greater than or equal to 1, each of the N storage rollers (R1, R2) supporting a membrane (M1, M2), said membrane being capable of moving from a configuration wound around a first main axis (X1, X2) to a configuration deployed along a first secondary axis (Y1, Y2) substantially perpendicular to the first main axis (X1, X2), and vice versa; a set of sensors (103) of the instantaneous position and instantaneous attitude of the vehicle (100); a device (104) for actuating at least one of the N storage rollers (R1, R2) between the wound configuration and the deployed configuration of the membrane (M1, M2) to place the vehicle (100) at a new instant position and an instant new attitude; a control (105) of the actuation device (104) according to the new instantaneous position and the new instantaneous attitude relative to the set position and the set attitude. Figure for abstract: Fig. 4

Description

Vehicle in orbit with roll-up and deployable membrane for attitude and orbit control

1. à la mise à poste de satellites géostationnaires (télécommunications). L’invention est alors utilisée avantageusement lors des passages à altitude basse, lors des premières orbites ;
2. à la désorbitation de satellites en orbite basse (en application de la loi relative aux opérations spatiales, pour tous types de plateformes, notamment les nano-satellites). L’invention est utilisée avantageusement lors des passages à altitude basse, lors de la rentrée.

The present invention relates to a satellite attitude and orbit control device. The invention applies in particular, and in a non-limiting manner, to satellites in low orbit around the Earth or any planet with an atmosphere using aerodynamic pressure, and more particularly:

1. the positioning of geostationary satellites (telecommunications). The invention is then used advantageously during passages at low altitude, during the first orbits;
2. the deorbiting of satellites in low orbit (in application of the law relating to space operations, for all types of platforms, in particular nano-satellites). The invention is advantageously used during passages at low altitude, during reentry.

The invention is described with the example of a satellite in low orbit, but it also applies to all types of vehicles in geostationary orbits or in interplanetary orbits using solar radiation pressure.

To allow the use of the various instruments for the mission of a satellite, such as telecommunications systems, it is necessary to be able to control the position and the orientation of the satellite in orbit. In addition to the gravitational pull of the earth, a satellite experiences several forces of smaller magnitudes, as well as aerodynamic pressure which gradually disturb its position and orientation. The gravitational attraction of the sun and the moon, the deformation of the earth at the equator, or the solar radiative pressure generate drifts that should be corrected. In particular, at low altitude, the aerodynamic pressure has a major impact on the attitude of the satellite. Control systems are implemented to maintain on the one hand the orientation of the satellite relative to the earth, this is attitude control, and on the other hand its position in orbit relative to a desired ideal position. , this is orbit control.

A satellite is put into orbit by the combination of a launcher space vehicle and its own propulsion systems. The launcher transports and releases the satellite into a first so-called transfer terrestrial orbit, the perigee of which is generally low; once in this first orbit, a satellite propulsion system takes over to transport the satellite to its final orbit. Generally, this transfer is carried out by means of a main satellite thruster PSP consuming a chemical fuel of the propellant or propellant type, delivering a high-power thrust making it possible to quickly reach the final orbit. This transfer can also be carried out by means of electric thrusters, delivering low thrusts, the final orbit being reached after several months.

We can note the critical aspect of the first orbits after the separation of the launcher. Often the perigee is very low and this causes greater interaction with the atmosphere. In this situation, the torque requirement to maintain the attitude of the satellite is high and requires the use of actuators (wheels, thrusters, etc.).

Once stationed, several secondary thrusters of lower power maintain the satellite in position in orbit. For this, propellant chemical thrusters or electric thrusters can be used. In an electric thruster, of the plasma thruster or ion thruster type, xenon atoms are ionized by collision with electrons, creating xenon ions. Thrust is generated when charged xenon ions are accelerated out of the thruster by an electromagnetic field. Although expensive and of large initial mass, the efficiency of the electric thruster, or its ability to generate force by mass ejection, also called specific impulse, is significantly greater than that of chemical thrusters.

In known systems, chemical thrusters and electric thrusters are positioned at several locations on the structure of the satellite to meet all the needs of the mission, from transport from the transfer orbit to maintenance in orbit throughout the life of the satellite. The propulsion systems thus implemented have the drawback of a high cost and a high mass, of the various propellants and of the fuel. These drawbacks limit the payload onboarding capacity of the satellite.

According to the known state of the art, an orbit control system seeks to control the position of the satellite through six orbital parameters. There represents a satellite 10 in orbit 11 around the Earth 12. The orbit 11 is inclined at an angle θ with respect to the equatorial plane 13 which contains the ideal objective orbit 14. The orbit 11 of the satellite intersects the equatorial plane 13 at two points 15 and 16, commonly called orbital nodes. Orbit control consists in quantifying these orbital parameters and carrying out the necessary operations by means of the on-board propulsion systems, to maintain the satellite in a predefined zone in a set position.

A common architecture of a satellite 10, as shown in the , comprises a parallelepipedal structure 20 on which are fixed various devices useful for piloting the satellite 10 and its mission. Telecommunications or observation instruments 21 are installed on a face 22 whose orientation is maintained in the direction of the planet. On two opposite side faces 24 and 25 due to their orientation with respect to the equatorial plane, are positioned two sets of solar panels 26 and 27 allowing the supply of electrical energy to the on-board systems. Various devices can be embedded on the side faces 28 and 29. Maintaining a constant orientation of the satellite relative to the planet is necessary for the smooth running of the satellite's mission, for example for the orientation of the solar panels 26 and 27 or the pointing of the telecommunications or observation systems 21 towards the planet. This is achieved by means of an attitude control system. Several attitude control systems capable of detecting and correcting orientation errors are known. Thus, the measurement of the orientation of the satellite can be carried out by means of a set of sensors. From these measurements, satellite orientation corrections around its center of gravity can be made, for example by means of a set of inertia wheels 31, gyroscopic actuators, magneto-couplers, thrusters.

A satellite equipped with such a system allowing attitude control is said to be stabilized on three axes. Typically, by controlling the speed of rotation and the orientation of the inertia wheels, we know how to correct an orientation error in a reference trihedron linked to the satellite. In the following, we call Z an axis directed towards the planet, also called yaw axis, Y an axis perpendicular to the orbit and oriented in the opposite direction to the angular momentum of the orbit, also called pitch axis, and X an axis forming with Y and Z a direct orthogonal reference, also called roll axis which is oriented according to the speed in the case of circular orbits.

For orbit control, a number of thrusters around the satellite hull are present to perform the various orbit maneuvers.

Thus, during its orbit, the attitude, or orientation in rotation, of the satellite must be modified and constantly controlled so that its pointing remains in the desired direction, according to the needs of the mission. In addition, the attitude of satellites is disturbed by environmental effects, such as solar pressure at high altitude, aerodynamic forces at low altitude, electromagnetic effects with the earth's magnetic field, the gravity gradient effect tending to modify their orientation. These attitude disturbances must also be controlled.

Sensors and actuators, for example flywheels, magnetocouplers, nozzles, and automatic algorithms are used to perform this control.

In the particular case of a passage at a relatively low altitude (deorbit or passage at perigee in LEOP, acronym of the Anglo-Saxon term Launch and Early Orbit phase, meaning launch and orbiting phase), the aerodynamic torques become the majority torques exerted on the satellite. These torques depend directly on the shape of the satellite which is not optimized for this particular phase because it is not part of the satellite's mission. Thus, the nominal shape of the satellite for its mission may be naturally unstable and/or not suitable for passage at low altitude, making the satellite aerodynamically unstable or creating excessive torques that cannot be compensated with the inertia wheels usually available on board. .

The use of additional surfaces to facilitate the attitude control of a satellite has been known for several decades. However, the additional surfaces of the prior art are often fixed and are used for passive stabilization, or exclusively for deorbiting.

Another solution of the prior art proposes orientable surfaces, but the latter have a fixed area and therefore does not present any adaptation in their deployment.

Finally, there are solutions in which the deployed surfaces are completely collapsible. This is an “all or nothing” solution: the surface is either fully extended or fully folded. Such a solution does not offer adaptation in its deployment.

The invention aims to overcome all or part of the problems mentioned above by proposing an attitude and orbit control device for a vehicle in orbit comprising at least one membrane capable of moving between a rolled up position and a deployed position, allowing to create at will on the vehicle a torque and a force that can be continuously configured in a wide range, while being reversible and of very small size. The deployment and winding, total or partial, of the membrane(s) allows attitude and orbit control of the vehicle while guaranteeing its stability in the adopted position. The invention also makes it possible to facilitate the first passages at perigee after the separation of the launcher.

1. une caisse ;
2. N rouleaux de stockage reliés à la caisse, N étant un entier supérieur ou égal à 1, chacun des N rouleaux de stockage supportant une membrane, ladite membrane étant apte à passer d’une configuration enroulée autour d’un premier axe principal à une configuration déployée selon un premier axe secondaire sensiblement perpendiculaire au premier axe principal, et vice versa ;
3. un ensemble de capteurs de la position instantanée et l’attitude instantanée du véhicule;
4. un dispositif d’actionnement d’au moins un parmi les N rouleaux de stockage entre la configuration enroulée et la configuration déployée de la membrane pour placer le véhicule à une nouvelle position instantanée et une nouvelle attitude instantanée;
5. un asservissement du dispositif d’actionnement selon la nouvelle position instantanée et la nouvelle attitude instantanée par rapport à la position de consigne et l’attitude de consigne.

To this end, the subject of the invention is a vehicle in orbit having an instantaneous position and an instantaneous attitude, said vehicle being intended to assume a set position and a set attitude in its orbit, comprising:

1. the cash register ;
2. N storage rollers connected to the box, N being an integer greater than or equal to 1, each of the N storage rollers supporting a membrane, said membrane being capable of passing from a configuration wound around a first main axis to a configuration deployed along a first secondary axis substantially perpendicular to the first main axis, and vice versa;
3. a set of sensors for the instantaneous position and the instantaneous attitude of the vehicle;
4. a device for actuating at least one of the N storage rollers between the rolled-up configuration and the deployed configuration of the membrane to place the vehicle in a new instantaneous position and a new instantaneous attitude;
5. servo-control of the actuation device according to the new instantaneous position and the new instantaneous attitude with respect to the setpoint position and the setpoint attitude.

In one embodiment, the first main axis is substantially parallel to an edge of the body, preferably substantially coinciding with an edge of the body.

In another embodiment, the vehicle may comprise a mast having a first end called the base and a second end, opposite the base, the base being connected to the body, the mast supporting at least one of the N storage rollers.

In another embodiment, at least one of the N storage rollers is rotatable relative to the body along the first main axis associated with it.

In another embodiment, at least one of the N storage rollers is rotatable relative to the body along the first secondary axis associated with it.

In another embodiment, the membrane of at least one of the N storage rolls can be covered at least partially on one side with a coating optimized for the use of solar radiation pressure.

In another embodiment, the membrane of at least one of the N storage rollers can be covered at least partially on one side with a coating suitable for the use of aerodynamic drag.

In another embodiment, at least one of the N storage rollers further comprises at least two measuring tapes, each being capable of passing from a configuration wound around the first main axis to a configuration deployed along the first secondary axis, and vice versa, the membrane extending between the at least two measuring tapes.

In another embodiment, the membrane of at least one of the N storage rolls comprises a final end rigidly attached to a fixed anchor relative to the storage roll associated with it.

In a particular embodiment of the invention, the vehicle is a satellite.

The invention will be better understood and other advantages will appear on reading the detailed description of an embodiment given by way of example, description illustrated by the attached drawing in which:

There schematically represents a satellite in orbit around the Earth;

There schematically represents a common architecture of a satellite comprising a structure on which are fixed various devices useful for piloting the satellite and for its mission;

There schematically represents a satellite in orbit with a rollable and deployable membrane for attitude and orbit control, in a rolled-up configuration according to the invention;

There schematically represents a satellite in orbit with a rollable and deployable membrane for attitude and orbit control, in the deployed configuration according to the invention;

There schematically represents a rollable and deployable membrane with a free end according to the invention;

There schematically represents a rollable and deployable membrane with a fixed end according to the invention;

There schematically represents a variant comprising a support mast for the membranes according to the invention.

For the sake of clarity, the same elements will bear the same references in the different figures. In this application, the invention is presented with the non-limiting example of a satellite. Indeed, the invention does not only apply to a satellite, but it can apply to any vehicle in geostationary orbit or in interplanetary orbit.

There schematically represents a satellite in orbit around the Earth or in orbit around any other planet. It has already been described in the introduction.

There schematically represents a common architecture of a satellite comprising a structure on which are fixed various devices useful for piloting the satellite and for its mission. It has already been described in the introduction.

The invention relates to the attitude and orbit control of satellites in orbit. The attitude of satellites is disturbed by environmental effects, for example solar pressure at high altitude and aerodynamic forces at low altitude if the planet is surrounded by an atmosphere, tending to modify their orientation. These orientation disturbances must be controlled. The invention relates to this control by using additional surface(s) deployed around the satellite to voluntarily create a torque, by taking advantage of the environmental effects on these surfaces. In other words, the invention uses the environmental effects undergone by the satellite and which have the consequence of moving it away from its set position and attitude, to maintain it and/or return it to its set position and attitude. The principle of the invention is based on the continuous evolution of the additional surface(s) deployed around the satellite which can be deployed, rolled up, redeployed, oriented at will and in a continuous and reversible manner, in function of the position and the attitude of the satellite, and of the external constraints which it undergoes.

1. une caisse 101 ;
2. N rouleaux de stockage R₁, R₂, …, R_Nreliés à la caisse 101, N étant un entier supérieur ou égal à 1, chacun des N rouleaux de stockage R₁, R₂, …, R_Nsupportant une membrane M₁, M₂, …, M_N, ladite membrane étant apte à passer d’une configuration enroulée autour d’un premier axe principal X₁, X₂, …, X_Nà une configuration déployée selon un premier axe secondaire Y₁, Y₂, …, Y_Nsensiblement perpendiculaire au premier axe principal X₁, X₂, …, X_N, et vice versa ;
3. un ensemble de capteurs 103 de la position instantanée et de l’attitude instantanée du véhicule 100;
4. un dispositif d’actionnement 104 d’au moins un parmi les N rouleaux de stockage R₁, R₂, …, R_Nentre la configuration enroulée et la configuration déployée de la membrane M₁, M₂, …, M_Npour placer le véhicule 100 à une nouvelle position instantanée et une nouvelle attitude instantanée;
5. un asservissement 105 du dispositif d’actionnement 104 selon la nouvelle position instantanée et la nouvelle attitude instantanée par rapport à la position de consigne et l’attitude de consigne.

There schematically represents a satellite 100 in orbit with a rollable and deployable membrane for attitude and orbit control, in rolled-up configuration according to the invention. Vehicle 100 in orbit has instantaneous position and instantaneous attitude. The vehicle 100 is intended to assume a set position and a set attitude in its orbit. According to the invention, the vehicle 100 comprises:

1. a box 101;
2. N storage rollers R ₁ , R ₂ , …, R _N connected to the box 101, N being an integer greater than or equal to 1, each of the N storage rollers R ₁ , R ₂ , …, R _N supporting a membrane M ₁ , M ₂ , …, M _N , said membrane being capable of passing from a configuration wound around a first main axis X ₁ , X ₂ , …, X _N to a configuration deployed along a first secondary axis Y ₁ , Y ₂ , ..., Y _N substantially perpendicular to the first main axis X ₁ , X ₂ , ..., X _N , and vice versa;
3. a set of sensors 103 of the instantaneous position and the instantaneous attitude of the vehicle 100;
4. a device 104 for actuating at least one of the N storage rollers R ₁ , R ₂ , ..., R _N between the rolled-up configuration and the deployed configuration of the membrane M ₁ , M ₂ , ..., M _N to place the vehicle 100 at a new instantaneous position and a new instantaneous attitude;
5. a servo-control 105 of the actuation device 104 according to the new instantaneous position and the new instantaneous attitude with respect to the setpoint position and the setpoint attitude.

Body 101 is to be understood as any support in the vehicle.

In the foregoing, the new instantaneous position is the new position taken by the vehicle 100 and the new instantaneous attitude is the new attitude, that is to say orientation in space, taken by the vehicle 100 thanks to the actuation of the N storage rollers, that is to say following the combination of deployments and/or windings of 1 to N membranes. Furthermore, for each instantaneous position and attitude, one to N membranes can also be deployed/rolled up so as to provide the vehicle 100 with the required stability.

It should be noted that the invention is implemented on a satellite comprising traditional actuators (thrusters, reaction wheels, etc.) allowing standard attitude control. The implementation of the invention makes it possible to undersize these actuators, or even to eliminate some of them.

In addition, the satellite 100 traditionally comprises solar generators 40 allowing the supply of electrical energy to the on-board systems (in particular, among others, the sensors 103, the actuating device 104 of the rollers and the servo-control 105). It can also comprise elements 30, for example of telecommunications or any other appendix.

On the , the vehicle 100 comprises two storage rollers R1, R2. These two rollers support two membranes M1, M2, each being associated with its storage roller. Each of these two membranes is represented in a configuration wound around its first main axis (X1, X2) and can unroll along the first secondary axis (Y1 for the membrane M1 and Y2 for the membrane M2) substantially perpendicular to the first main axis ( X1, X2), and vice versa. This means that each membrane can switch from the coiled configuration to the deployed configuration and then from the deployed configuration to the coiled configuration. Each membrane can fully roll up and unfold, i.e. the entire surface of the membrane can either be fully rolled up or fully extended. But also each membrane can partially unfold and roll up, i.e. only a portion of the membrane is unfolded and the other part is rolled up, independently of the winding/unfolding state of a another membrane. The transition from one configuration (rolled up, deployed or intermediate) to a following configuration whatever it may be can be done jerkily, step by step, or even continuously according to an almost uninterrupted movement. The invention applies similarly with a single storage roll and therefore a single membrane, or else two, three, or preferably four, or even more.

Thanks to the deployment and winding mechanisms of the membrane(s), the area of the different surfaces of the deployed membrane(s) can be modified independently of each other, making it possible to create couples of different amplitude and direction if necessary. , using the environmental effects of aerodynamic drag and/or solar radiation pressure. The evolution of the torque thus created is continuous and configurable in a wide area.

The set of sensors 103, the actuation device 104 of the storage rollers and the servo-control 105 of the actuation device 104 are represented schematically but are not detailed further since they are sensors, traditional actuation and control known to those skilled in the art.

There schematically represents a satellite in orbit with a rollable and deployable membrane for attitude and orbit control, in the deployed configuration according to the invention. More precisely, the membrane M1 is fully deployed along its secondary axis Y1, and the membrane M2 is semi-deployed along its secondary axis Y2. The deployment length of each of the membranes is determined by the servo-control 105, from the instantaneous position and attitude, themselves impacted by the environmental effects, with respect to the set position and attitude that the satellite 100 must hold.

In one embodiment, the first principal axis X₁, X₂ (but also X₃, …, X_NOTin the case of N rolls) is substantially parallel to an edge of the body 101, preferably substantially coincident with an edge of the body 101. This embodiment has an advantage in terms of size and stability in the deployed configuration.

In another embodiment (not shown), the first principal axis X₁, X₂ (but also X₃, …, X_NOTin the case of N rollers) can be secant at an edge of the box 101.

As can be seen on the , at least one of the N storage rollers R1, R2, ..., RN can be rotatable relative to the body 101 along the first main axis X1, X2, ..., XN associated with it. In other words, in the case of two storage rollers R1 and R2 as in our non-limiting example, the storage roller R1 is rotatable around its main axis X1 and the storage roller R2 is rotatable around its axis main X2 with respect to the body 101. This allows an orientation of the membrane M1 deployed (or partially deployed) around the axis X1, and of the membrane M2 deployed (or partially deployed) around the axis X2.

Further, in another embodiment, at least one of the N storage rollers R₁, R₂, …, R_NOTcan be rotatable relative to the body along the first secondary axis Y₁, Y₂, …, Y_NOTwhich is associated with it. In other words, in the case of two storage rolls R₁and R₂as in our non-limiting example, the storage roll R₁is mobile in rotation around its secondary axis Y₁and storage roll R₂is mobile in rotation around its secondary axis Y₂relative to the body 101. This allows an orientation of the membrane M₁deployed (or partially deployed) around the Y axis₁, and the membrane M₂deployed (or partially deployed) around the Y axis₂. This may be the only possible rotation of the storage roller, but advantageously this rotation is to be coupled with the rotation around the main axis mentioned above. Thus, this allows an orientation of the membrane M₁deployed (or partially deployed) around the X axis₁ and the Y axis₁, and the membrane M₂deployed (or partially deployed) around the X axis₂ and the Y axis₂. Thanks to these degrees of freedom, each of the deployed or partially deployed membranes can be oriented along two axes of rotation by means of mechanisms located at the base of the associated storage roller. As a result, the direction of the torque created can be parameterized over a wide range.

The main axes X ₁ , X ₂ , …, X _N are not necessarily mutually parallel. They can be, according to the configurations considered, parallel, perpendicular or secant between them. The same is true for the secondary axes Y ₁ , Y ₂ , …, Y _N . They can be, according to the configurations considered, parallel, perpendicular or secant between them.

The deployed membrane or membranes allow the creation of a torque advantageously used in the satellite attitude control loop. This torque can for example be calibrated to reduce the total disturbing torques (and therefore reduce the capacity of the necessary actuators, or even eliminate some). This torque can be used to desaturate reaction wheels and/or reorient the satellite without activating other conventional actuators; and/or stabilize the satellite attitude. This torque can be used to turn the satellite in a desired direction without requiring the actuation of other actuators (reaction wheels, attitude nozzles, etc.).

The invention makes it possible to create at will on the satellites a torque that can be continuously parameterized in a wide range, in particular around the three axes of the satellite X, Y and Z. This created torque can be used advantageously in the attitude control loop of the satellite. For example, it can be calibrated to reduce the total disturbing torques and therefore reduce the capacity of the necessary actuators, or even remove some. This torque can be used to desaturate reaction wheels, and therefore reduce the capacity of the actuators necessary for desaturation, or even eliminate some. This torque can be used to turn the satellite in a desired direction without requiring the actuation of other actuators (reaction wheels, attitude nozzles, etc.).

The invention also makes it possible to create on the satellite a continuously configurable force which opposes the direction of the aerodynamic speed and which could also cause a certain lift in the perpendicular direction of the aerodynamic speed. This created force can be used in support of orbital control maneuvers, or even replace them.

The invention finally makes it possible to cancel a couple of aerodynamic pressure or solar radiation pressure when it is not useful for control. Thus, the invention makes it possible to control unwanted disturbances.

There schematically represents a rollable and deployable membrane M1 with a free end 120 according to the invention. According to the invention, at least one of the N storage rollers R1, R2, ..., RN can further comprise at least two measuring tapes 121, 122, each being capable of passing from a configuration wound around the first main axis X1 , X2, ..., XN to a configuration deployed along the first secondary axis Y1, Y2, ..., YN, and vice versa, the membrane M1, M2, ..., MN extending between the at least two measuring tapes 121, 122 .

In the space domain, measuring tapes are frequently used in deployment. In the stored (or rolled up) position, tape measures are wrapped around a mandrel. The deployment of the measuring tapes is ensured autonomously by their spontaneous unwinding when the mandrel is free to rotate. Measuring tapes are known in the space field as being flexible tapes having an arcuate section whose radius of curvature is convex on a first side and concave on a second side, these tapes being capable of passing from the state rolled up in the deployed state essentially thanks to their own elastic energy. There are different types of tape with their own properties. Monostable tapes have a natural deployed position and require maintenance in the stored position. Monostable measuring tapes therefore have a natural tendency to unfold and end up in their unrolled state. The deployment of monostable ribbons is often anarchic and uncontrolled. Bistable ribbons have two natural positions (rolled up position and extended position). Their deployment is linear and controlled. In the invention, it is the actuation device 104 which controls the deployment and winding of each measuring tape according to the need for deployed area and the required orientation of the membrane supported by the two measuring tapes. ribbons.

On the , only the membrane M1 is shown. It is supported by storage roll R1. Two measuring tapes 121, 122 are each able to pass from a configuration wound around the first main axis X1 to a configuration deployed along the first secondary axis Y1, and vice versa. The membrane M1 is wrapped around its main axis X1 and unfolds along its secondary axis Y1. The membrane M1 extends between the two measuring tapes 121, 122, and has a free end 120. It is therefore the deployment and winding of the measuring tapes 121, 122 which allow the deployment and winding of the M1 diaphragm.

Traditionally, guide elements can be added to come into contact with the measuring tapes. Such guide elements can take the form of point or linear supports on the tape measure in order to ensure its deployment in the right direction and to prevent them from "swelling" around the mandrel, i.e. that they release from their coiling in coiled configuration. These guide elements can be connected to the actuator 104 to control the deployment and winding of each tape measure.

As can be seen, the connection 80 allows the rotation of the storage roller R ₁ , and therefore of the membrane M ₁ , around the axis Y ₁ , and the connection 81 allows the rotation of the storage roller R ₁ , and therefore of the membrane M ₁ , around an axis parallel to the axis X ₁ . This is a non-limiting example of the embodiment of the rotational movements of the storage roller and therefore of the orientation of the membrane. The invention obviously applies to other rotation mechanisms.

There schematically represents a rollable and deployable membrane M1 with a fixed end 130 according to the invention. According to the invention, the membrane M1, M2, ..., MN of at least one of the N storage rollers R1, R2, ..., RN can comprise a final end 130 rigidly attached to an anchor 131 fixed relative to the storage roller R1, R2, …, RN associated with it. On the , only the membrane M1 is shown. It is supported by storage roll R1. The membrane may have at its final end 130 a point of attachment to the anchor 131 fixed with respect to the storage roll R1. Alternatively, the membrane M1 can extend between two measuring tapes 121, 122, as stated previously, and it is the final ends of each measuring tape which are connected to the fixed anchor point 131. As the final end 130 is fixed to the storage roller, we also speak of round-trip deployment because the membrane M1 is deployed along the axis Y1 and its first unfolded portion passes under the unfolded membrane to the point of anchor 131.

As before, it is advantageous to add occasional supports on the measuring tapes in order to prevent them "swelling" around the mandrel, that is to say that they relax from their winding in configuration rolled up.

The membranes M ₁ , M ₂ , ..., M _N can be made of a material eligible for the space domain. They can be made of polyimide film, also known as Kapton. It can be canvas based on carbon fibers or glass. The membranes M ₁ , M ₂ , ..., M _N can also be made of poly(p-phenyleneterephthalamide) (PPD-T) thermoplastic polymer (also known under the name Kevlar). A usable material may also be a thin layer of aluminum coating on a polymer (plastic) sheet, such as 2 µm (micrometer) aluminized Kapton film. The polymer provides mechanical support as well as flexibility, while the thin metallic layer provides reflectivity. Such a material resists heat and still remains reasonably strong. The aluminum reflective film is on the Sun side. An example is PET (short for poly(ethylene terephthalate)) aluminized (Mylar) film.

In another embodiment, the membrane M ₁ , M ₂ , ..., M _N of at least one of the N storage rollers R ₁ , R ₂ , ..., R _N can be covered at least partially on one face 111, 112 with a coating optimized for the use of solar radiation pressure. An example of implementation can be obtained by a polymer coating of Mylar and Kapton. Such a coating has a strong light-reflecting power.

In another embodiment, the membrane M ₁ , M ₂ , ..., M _N of at least one of the N storage rollers R ₁ , R ₂ , ..., R _N can be covered at least partially on one face 112, 111 of a coating adapted to the use of aerodynamic drag. The coating is adapted to the use of aerodynamic drag, ie resistant to a particulate flow and to thermal stresses. It may for example be PEEK (abbreviation for polyetheretherketone), PET (abbreviation for poly(ethylene terephthalate)), Kapton, FEP (abbreviation for Fluorinated ethylen propylene for fluorinated ethylene propylene).

The coating suitable for the use of aerodynamic drag can be on the same face as the coating optimized for the use of solar radiation pressure. For example, a distal portion of the face (towards the end of the membrane in the deployed configuration) can be covered with the coating adapted to the use of aerodynamic drag and a proximal portion (near the storage roller) can be covered coating optimized for the use of solar radiation pressure. This combination is possible in particular on round-trip membranes. A variant on the free-end membranes is to cover one face of the membrane with the coating suitable for the use of aerodynamic drag and the opposite face with the coating optimized for the use of the solar radiation pressure. In the latter case, a rotation of the membrane around the secondary axis Y ₁ , Y ₂ makes it possible to orient the adapted face of the membrane considered according to the effects to which the vehicle 100 is subjected.

There schematically represents a variant comprising a support mast 106 for the membranes M1, M2, ..., MN according to the invention. According to a variant of the invention, the satellite 100 can comprise a mast 106 having a first end 107 called the base and a second end 108, opposite the base, the base being connected to the body 101, the mast 106 supporting at least one N storage rolls R1, R2, …, RN. On the , the mast 106 supports two storage rollers R1, R2. Such a mast has the advantage of being able to offset the deployment of the membranes. In addition, the mast 106 can include several pivot links allowing many other rotations, and thus result in various orientations of the deployed surfaces of membranes. The configuration shown in is by way of example and does not limit the scope of the invention. Other links can be implemented without departing from the scope of the invention.

The connection 90 allows the rotation of the assembly of the mast 106 according to an axis substantially parallel to a surface of the body 101 of the satellite. Mast 106 may include another link 93 allowing rotation of the end of mast 106 along an axis substantially parallel to said surface of body 101. Finally, mast 106 may be extended by two distancing arms 94, 95, each of the distance arms 94, 95 supporting a storage roll. The angle formed between these two arms 94, 95 can be fixed or it can be made variable by a pivot link (not present on the ). The end of each distance arm may include a pivot link 91, 92 connected to one of the storage rollers. The pivot links 91, 92 allowing the rotation of the storage rollers R1, R2, each along an axis S1, S2, substantially perpendicular to their main axis X1, X2. By combining all the possible rotations, the membranes can be oriented as desired depending on the environmental effects. The rotations are implemented by the actuation device 104, in a manner known to those skilled in the art, according to the commands that it receives, based on the servo-control 105. It can be noted that the rotational mobilities indicated on are for example only, and that other rotations can be implemented. It is also possible to provide translational movements, for example by means of telescopic mast portions. The invention is not limited to the embodiments described above by way of non-limiting example. It encompasses all the variant embodiments which may be envisaged by those skilled in the art. In particular, those skilled in the art will understand that the invention is not limited to specific rotations as described, nor to a particular type of vehicle.

On the , the membranes are represented with an out-and-back deployment. The invention also applies with a mast 106 and deployment membranes with a free end.

The invention proposes a solution for controlling position and attitude in the orbit of a vehicle by deploying and orienting surfaces of variable area over time according to control needs. This solution is reversible and configurable. The membranes can be completely folded up during the phases of the mission where they are not useful, thus avoiding any disturbance in these phases. In the rolled-up configuration, the size of the membranes is small and the shape of the storage rolls allows optimization of the use of the space available under the fairing of the launcher. The invention has the advantage of being generic and usable for any type of platform. By adapting the size of the rollers and membranes to the size of the satellite, and therefore to the torque that we want to generate, the proposed solution can be used on different types of satellite, for example from nanosatellites to large telecommunications satellites. Position and attitude control, as well as vehicle stability, is achieved using the environmental effects of aerodynamic drag and/or solar radiation pressure. The entire control device is controlled to produce a variable torque at the vehicle level, this torque being created by the environmental effects on the properly deployed and oriented surfaces. This torque is used in the vehicle attitude control loop for a reduction in disturbing torques, setting the vehicle in motion, desaturation of reaction wheels. The domain of the couple thus created is wide and continuous. In addition, the use of environmental effects to reduce the onboard mass, both in fuel and also in actuators which can be smaller in size and/or in fewer numbers.

Claims (10)

Vehicle (100) in orbit having an instantaneous position and an instantaneous attitude, said vehicle (100) being intended to assume a setpoint position and a setpoint attitude in its orbit, characterized in that it comprises:

1. a crate (101);
2. N storage rollers (R1, R2, …, RN) connected to the box (101), N being an integer greater than or equal to 1, each of the N storage rollers (R1, R2, …, RN) supporting a membrane ( M1, M2, ..., MN), said membrane being capable of passing from a configuration wound around a first main axis (X1, X2, ..., XN) to a configuration deployed along a first secondary axis (Y1, Y2, …, YN) substantially perpendicular to the first main axis (X1, X2, …, XN), and vice versa;
3. a set of sensors (103) of the instantaneous position and the instantaneous attitude of the vehicle (100);
4. an actuating device (104) of at least one of the N storage rollers (R1, R2, …, RN) between the rolled-up configuration and the deployed configuration of the membrane (M1, M2, …, MN) to place the vehicle (100) at a new instantaneous position and a new instantaneous attitude;
5. a servo-control (105) of the actuation device (104) according to the new instantaneous position and the new instantaneous attitude with respect to the setpoint position and the setpoint attitude.

Vehicle (100) according to claim 1, in which the first main axis (X ₁ , X ₂ , ..., X _N ) is substantially parallel to an edge of the body (101), preferably substantially coinciding with an edge of the body ( 101). Vehicle (100) according to claim 1, comprising a mast (106) having a first end (107) called the base and a second end (108), opposite the base, the base being connected to the body (101), the mast (106) supporting at least one of the N storage rollers (R ₁ , R ₂ , ..., R _N ). Vehicle (100) according to one of claims 1 to 3, in which at least one of the N storage rollers (R ₁ , R ₂ , ..., R _N ) is rotatable relative to the body (101) according to the first main axis (X ₁ , X ₂ , …, X _N ) associated with it. Vehicle (100) according to one of claims 1 to 4, in which at least one of the N storage rollers (R ₁ , R ₂ , …, R _N ) is rotatable relative to the body along the first secondary axis (Y ₁ , Y ₂ , …, Y _N ) associated with it. Vehicle (100) according to one of Claims 1 to 5, in which the membrane (M ₁ , M ₂ , …, M _N ) of at least one of the N storage rollers (R ₁ , R ₂ , …, R _N ) is covered at least partially on one side (111, 112) with a coating optimized for the use of solar radiation pressure. Vehicle (100) according to one of Claims 1 to 6, in which the membrane (M ₁ , M ₂ , …, M _N ) of at least one of the N storage rollers (R ₁ , R ₂ , …, R _N ) is covered at least partially on one face (112, 111) with a coating adapted to the use of aerodynamic drag. Vehicle (100) according to one of Claims 1 to 7, in which at least one of the N storage rollers (R ₁ , R ₂ , …, R _N ) further comprises at least two measuring tapes (121, 122) , each being capable of passing from a configuration wound around the first main axis (X ₁ , X ₂ , …, X _N ) to a configuration deployed along the first secondary axis (Y ₁ , Y ₂ , …, Y _N ), and vice versa, the membrane (M ₁ , M ₂ , …, M _N ) extending between the at least two measuring tapes (121, 122). Vehicle (100) according to one of Claims 1 to 8, in which the membrane (M ₁ , M ₂ , …, M _N ) of at least one of the N storage rollers (R ₁ , R ₂ , …, R _N ) comprises a final end (130) rigidly attached to an anchor (131) fixed relative to the storage roll (R ₁ , R ₂ , …, R _N ) which is associated with it. A vehicle (100) according to any of claims 1 to 9, said vehicle being a satellite.