Hold-down and release system for stacked spacecraft

Abstract

Hold-down and release system (10) for stacked spacecraft (7), configured to change from a hold-down position to a released position with respect to a launcher (13), said system comprising at least one sub-system (20, 20'), each sub-system (20, 20') comprising: - a cable relaxation and rolling assembly configured to be attached to the launcher (13) and comprising: - an inertia drum (2), - an articulated lever (3) configured for engagement and disengagement with the inertia drum (2) at a first end (11) of the articulated lever (3), - an actuator (4) connected to the inertia drum (2) and configured to trigger same, - a cable (5) comprising a first fitting (8), configured to engage with the articulated lever (3) at a second end (12) of the articulated lever (3), and having one of its ends connected to the inertia drum (2), such that the cable (5) can be wound on the inertia drum (2), and additionally comprising a second fitting (9) on the second end of the cable (5), and - a release mechanism (6), configured to be attached to one end of the outermost stacked spacecraft (1), and to hold the second fitting (9) placed on the second end of the cable (5) in the hold-down position, wherein in the hold-down position the articulated lever (3) is engaged with the inertia drum (2) and the first fitting (8) of the cable (5), and the cable (5) is tensioned between the first fitting (8) and the second fitting (9) to keep the stacked spacecraft (7) together, and in the release position the articulated lever (3) is disengaged from the inertia drum (2) and the first fitting (8) of the cable (5).

Description

[0001] RETENTION AND RELEASE SYSTEM FOR STACKED SPACECRAFT

[0002] Field of invention

[0003] The present invention relates to a retention and release system for stacked spacecraft, particularly applicable to stacked satellites that need to be secured during launch and released once in orbit. However, it can also be applied to other elements and configurations.

[0004] Background

[0005] Release systems for securing spacecraft to the launch vehicle so they remain attached during the launch event and are released at the injection point in orbit are currently based on various types of pre-tensioned fastenings: bars, retainers, retaining bands, or multi-point release devices activated by pyrotechnics and / or non-explosive actuators. Each fastening is best suited for a specific type of component to be separated and its particular configuration. In the case of stacked spacecraft, tensioned bars have been the preferred option to date.

[0006] Upon activation, the retention and release systems free the spacecraft for ejection. Part of the retention and release system remains with the upper spacecraft or is ejected as debris from the launch package, which could impact flight hardware. The remainder of the retention and release system stays in the lower interface (launcher adapter / dispenser structure).

[0007] As mentioned, current systems for securing and releasing stacked spacecraft use bars. In some designs, these bars are ejected after use, thus generating space debris.

[0008] The actuation and release sequence is complex, as it involves two or more actuators.

[0009] The retention and release system generates an unwanted shock due to the sudden reduction in tension caused by the triggering device and the energy dissipation of the de-tensioned structures. The relaxation of tension in the bars, without energy dissipation, emits shocks at levels that compromise sensitive equipment within the launcher and the spacecraft's survival.

[0010] Retention and release systems require coordination of activation with mission stages. Sometimes, more than one signal is requested simultaneously for controlled release events, and a device is also required to provide these sequenced energy signals. This adds further elements to the space system architecture.

[0011] Therefore, it would be desirable to have a retention and release system for stacked spacecraft with fewer elements that does not emit waste, allows for reduced collisions, and also minimizes excess mass in the upper structure.

[0012] Summary of the invention

[0013] Therefore, it is an object of the invention to provide a retention and release system for stacked spacecraft that is capable of overcoming the aforementioned drawbacks.

[0014] The invention provides a retention and release system for stacked spacecraft, configured to move from a retention position to a release position with respect to a launcher, characterized in that it comprises at least one subsystem, each subsystem comprising:

[0015] - a cable relaxation and winding assembly configured to be attached to the launcher, comprising:

[0016] - an inertia drum,

[0017] - an articulated lever configured to engage and disengage with the inertia drum at a first end of the articulated lever,

[0018] - an actuator connected to the inertia drum and configured to actuate it,

[0019] - a cable comprising a first accessory element configured to attach to the articulated lever at a second end of the articulated lever, and having one end connected to the inertia drum so that the cable can be wound onto the inertia drum, and further comprising a second accessory element at the second end of the cable, and

[0020] - a release mechanism, configured to attach to one end of the outermost stacked spacecraft, and to hold the second accessory element positioned at the second end of the cable in the retention position, wherein, in the retention position, the articulated lever is coupled to the inertia drum and the first accessory element of the cable, and the cable is tensioned between the first accessory element and the second accessory element to hold the stacked spacecraft together, and, in the release position, the articulated lever is uncoupled from the inertia drum and the first accessory element of the cable.

[0021] The system of the invention has the following advantages:

[0022] The excess mass in the outermost of the stacked spacecraft that is to be separated is minimized (the release mechanism). No additional hardware is added to the other spacecraft.

[0023] No waste is created at the time of release.

[0024] The induced shock is significantly lower than in prior art systems.

[0025] - A single actuator, requiring minimal signal energy, is used for tension relaxation, release, and winding functions.

[0026] Other features and advantages of the present invention will become clear from the following detailed description of an illustrative and non-limiting embodiment of its object in relation to the accompanying figures.

[0027] Description of the figures

[0028] Figure 1 shows the retention and release system for stacked spacecraft of the invention in the retention position, corresponding to the flight configuration when the spacecraft are attached to the launcher.

[0029] Figure 2 shows the retention and release system for stacked spacecraft of the invention in the released position immediately after activation of the actuator.

[0030] Figure 3 shows the retention and release system for stacked spacecraft of the invention during cable storage around the inertia drum.

[0031] Figure 4 shows the stacked spacecraft retention and release system of the invention with the final position of the cable on the launcher, and the release of the spacecraft.

[0032] Detailed description of the invention

[0033] Figure 1 shows the retention and release system 10 for stacked spacecraft 7 of the invention in the retention position. A launcher 13 is also shown. The system 10 comprises at least one subsystem 20, 20'; in the embodiment of Figures 1, 2, and 3, the system 10 comprises two subsystems 20, 20', which may be arranged symmetrically.

[0034] Each subsystem 20, 20' has the following elements: - a cable relaxation and winding assembly configured to be fixed to the launcher 13, comprising:

[0035] - an inertia drum 2,

[0036] - an articulated lever 3 configured to engage and disengage with the inertia drum 2 at a first end 11 of the articulated lever 3, and

[0037] - an actuator 4 connected to the inertia drum 2 and configured to actuate it.

[0038] Each subsystem 20, 20' further comprises a cable 5 comprising a first accessory element 8, configured to couple with the articulated lever 3 at a second end 12 of the articulated lever 3, and with one of its ends connected to the inertia drum 2, so that the cable 5 can be wound on the inertia drum 2, and further comprising a second accessory element 9 at the second end of the cable 5.

[0039] Each subsystem 20, 20' also comprises a release mechanism 6, configured to attach to one end of the outermost stacked spacecraft 1, and to hold the second accessory element 9 located at the second end of cable 5 in the retention position. The outermost stacked spacecraft 1 is considered to be the spacecraft in the spacecraft stack farthest from the launcher.

[0040] Figure 1 shows the retention position, which corresponds to the configuration of system 10 during flight. In this position, the articulated lever 3 is coupled to the inertia drum 2 and the first accessory element 8 of cable 5. Cable 5 is tensioned between the first accessory element 8 and the second accessory element 9 to hold the stacked spacecraft 7 together as it passes through the stacked spacecraft 7.

[0041] Actuator 4 can activate the movement of the corresponding retention and release subsystem 20 by uncoupling the inertia drum 2. This allows the articulated lever 3 to rotate (see Fig. 2), causing the initial rotation of the inertia drum 2 and the winding of the cable 5 onto the inertia drum 2. The articulated lever 3 then uncouples, releasing the tension on the cable 5, and the rotation of the inertia drum 2 accelerates. As shown in Fig. 2, in the release position, the articulated lever 3 is uncoupled from the inertia drum 2 and the first accessory element 8 of the cable 5.

[0042] The loss of tension in the cable allows the release mechanism 6 to open, thereby allowing the second accessory element 9 from the second end of cable 5 to pass through the release mechanism 6. Retraction of cable 5 is thus made possible, and cable 5 winds onto the inertia drum 2 as it rotates (see Figure 3). After these steps, cable 5, along with its first accessory element 8, is wound onto the inertia drum 2, the release mechanism 6 remains attached to the outermost spacecraft 1 of the stack, and no debris is released into space (Figure 4).

[0043] After actuating the actuator 4, the elastic energy of the cable 5 drives the rotation of the inertia drum 2 to wind the cable 5, as described above.

[0044] There may also be a coil spring connected to the inertia drum 2 to maintain and / or accelerate and / or a discharge system to slow the rotation speed of the inertia drum until the cable 5 is fully wound up.

[0045] The release system for stacked spacecraft 7 may comprise a base member comprising a stop for limiting the rotation of the articulated lever 3 and a retainer that holds the articulated lever and prevents it from bouncing unintentionally.

[0046] In one embodiment, the stacked spacecraft 7 are stacked satellites.

[0047] Several types of actuators can be used 4.

[0048] Although the present invention has been fully described in relation to the preferred embodiments, it is evident that modifications can be made within the scope, without considering it limited by these embodiments, but by the content of the following claims.

Claims

CLAIMS 1.- Retention and release system (10) for stacked spacecraft (7), configured to move from a retention position to a release position with respect to a launcher (13), characterized in that it comprises at least one subsystem (20, 20'), each subsystem (20, 20') comprising: - a cable relaxation and winding assembly configured to be attached to the launcher (13), comprising: - an inertia drum (2), - an articulated lever (3) configured to engage and disengage with the inertia drum (2) at a first end (1 1 ) of the articulated lever (3), - an actuator (4) connected to the inertia drum (2) and configured to actuate it, - a cable (5) comprising a first accessory element (8), configured to be coupled to the articulated lever (3) at a second end (12) of the articulated lever (3), and having one end connected to the inertia drum (2), so that the cable (5) can be wound onto the inertia drum (2), and further comprising a second accessory element (9) at the second end of the cable (5), and - a release mechanism (6), configured to be attached to one end of the outermost stacked spacecraft (1), and to hold the second accessory element (9) positioned at the second end of the cable (5) in the retaining position, wherein, in the retaining position, the hinged lever (3) is coupled to the inertia drum (2) and to the first accessory element (8) of the cable (5), and the cable (5) is tensioned between the first accessory element (8) and the second accessory element (9) to hold the stacked spacecraft (7) together, and, in the release position, the hinged lever (3) is uncoupled from the inertia drum (2) and from the first accessory element (8) of the cable (5). 2.- Retention and release system (10) for stacked spacecraft (7), according to claim 1, wherein the stacked spacecraft (7) are stacked satellites. 3.- Retention and release system (10) for stacked spacecraft (7), according to any of the preceding claims, wherein the articulated lever (3) is configured to rotate about a base member comprising a stop to limit the rotation of the articulated lever (3) and a retainer to hold it.

4. A retention and release system (10) for stacked spacecraft (7), according to any of the preceding claims, wherein each subsystem comprises a coil spring connected to the inertia drum to maintain and / or accelerate the rotation of the inertia drum.

5. A retention and release system (10) for stacked spacecraft (7), according to any of the preceding claims, wherein each subsystem comprises a release system to slow the rotation of the inertia drum. 6.- Retention and release system (10) for stacked spacecraft (7), according to any of the preceding claims, comprising two symmetrically arranged subsystems (20, 20').

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