Separable clamped HDRM interface for managing torsion loads
A Hold Down Release Mechanism, HDRM, interface for attachment of a spacecraft to an adjacent structure of a launch vehicle or another spacecraft, wherein the HDRM interface is configured for forming part of a single or multi-point releasable attachment of the spacecraft to said adjacent structure. The HDRM interface includes first and second connector parts, wherein one of the first and second connector parts is fastened to said adjacent structure, and other is fastened to the spacecraft; wherein the first connector part has a tapered projection with a non-circular external surface; wherein the second connector part has a tapered recess with a non-circular interior surface configured for form-lockingly receiving the tapered projection, for enabling transfer of torsion and shear load between the first and second connector parts, when the tapered projection is inserted in the tapered recess and the first and second connector parts are pressed together.
1. A Hold Down Release Mechanism (HDRM) interface for attachment of a spacecraft to an adjacent structure of a launch vehicle or to an adjacent structure of another spacecraft carried by the launch vehicle, wherein the HDRM interface is configured for forming part of a single-point or multi-point releasable attachment of the spacecraft to said adjacent structure, the HDRM interface comprising:
a first connector part and a second connector part, wherein one of the first and second connector parts is configured to be fastened to said adjacent structure, and the other of the first and second connector parts is configured to be fastened to the spacecraft,
wherein the first connector part has a tapered projection with a non-circular external surface in a plane perpendicular to a release direction of the HDRM interface,
wherein the second connector part has a matching formed tapered recess with a non-circular interior surface configured for form-lockingly receiving the tapered projection, for enabling transfer of at least torsion load and shear load between the first and second connector parts, when the tapered projection is inserted in the tapered recess and the first and second connector parts are pressed together,
wherein the tapered projection of the first connector part has the shape of a truncated or non-truncated substantially triangular pyramid, and the tapered recess of the second connector part has the shape of a truncated or non-truncated inverse substantially triangular pyramid,
wherein an exterior outline of a cross-section of the tapered projection of the first connector part, in a plane perpendicular to a release direction of the HDRM interface, has three substantially straight lateral sides with substantially equal length, and
wherein both the tapered projection of the first connector part and the tapered recess of the second connector part have a central through-hole for receiving a release bolt configured to clamp the first and second connector parts together.
2. The HDRM interface according to claim 1 , wherein a lateral surface area of the tapered projection of the first connector part is defined by a set of substantially flat lateral sides mutually connected via sharp or rounded or bevelled lateral edges, and wherein a lateral surface area of the tapered recess of the second connector part is defined by a set of substantially flat lateral sides mutually connected via sharp or rounded or bevelled lateral edges.
3. The HDRM interface according to claim 1 , wherein the tapered projection of the first connector part has a shape of truncated or non-truncated pyramid with odd number of main lateral sides, and the tapered recess of the second connector part has the shape of an inverse truncated or non-truncated pyramid with odd number of main lateral sides.
4. The HDRM interface according to claim 3 , wherein the tapered projection of the first connector part has the shape of a truncated triangular pyramid, and the tapered recess of the second connector part has the shape of a truncated inverse triangular pyramid.
5. The HDRM interface according to claim 1 , wherein an exterior outline of a cross-section of the tapered projection of the first connector part, in a plane perpendicular to a release direction of the HDRM interface, has three substantially straight lateral sides that are mutually connected by sharp or at least one of rounded or bevelled lateral edges.
6. The HDRM interface according to claim 1 , wherein an exterior outline of a cross-section of the tapered recess of the second connector part, in a plane perpendicular to a release direction of the HDRM interface, has three substantially straight lateral sides that are mutually connected by at least one of rounded or bevelled lateral edges.
7. The HDRM interface according to claim 1 , wherein an effective minimal contact length of a straight lateral side of an exterior outline of a cross-section of the tapered projection of the first connector part, in a plane perpendicular to a release direction of the HDRM interface, is at least 50% of a length of oppositely facing straight lateral side of the tapered recess of the second connector part, in said plane.
8. The HDRM interface according to claim 1 , wherein an effective minimal total contact length of an exterior outline of a cross-section of the tapered projection of the first connector part, in a plane perpendicular to a release direction of the HDRM interface, is at least 50% of a length of oppositely facing interior outline of a cross-section of the tapered recess of the second connector part, in said plane.
9. The HDRM interface according to claim 1 , wherein an exterior surface of a substantially flat lateral side of the tapered projection of the first connector part define a tapering angle, relative to a release direction of the HDRM interface, in the range of 5-45°.
10. The HDRM interface according to claim 1 , wherein each of the first and second connector parts has an attachment flange for attachment to the said adjacent structure and spacecraft, respectively, wherein the attachment flange of each connector part has a plurality of holes for receiving fasteners.
11. The HDRM interface according to claim 1 , wherein the non-circular external surface of the tapered projection of the first connector part, and the matching formed tapered recess of the second connector part, jointly provides a play-free connection between the first and second connector parts, when the tapered projection is inserted in the tapered recess and the first and second connector parts are pressed together by a release bolt.
12. A launch vehicle carrying a first spacecraft, which is releasably attached to an adjacent structure of the launch vehicle or to an adjacent structure of a second spacecraft carried by the launch vehicle by means of a singular or plurality of HDRM interfaces in a single-point or multi-point attachment of the first spacecraft for enabling controlled release of the first spacecraft, wherein each of the singular or plurality of HDRM interfaces is defined according to claim 1 , wherein one of the first and second connector parts of each of the singular or plurality of HDRM interfaces is fastened to the said adjacent structure, and the other of the first and second connector parts of each of the singular or plurality of HDRM interfaces is fastened to the first spacecraft, and wherein a release bolt extends through the central through-hole of the first and second connector parts of each of the singular or plurality of HDRM interfaces and clamps said first and second connector parts together.
13. A method for mounting a first spacecraft to an adjacent structure of a launch vehicle or of a second spacecraft using a singular or plurality of Hold Down Release Mechanism (HDRM) interfaces forming part of a single-point or multi-point attachment of the first spacecraft to said adjacent structure, the method comprising:
providing a singular or plurality of HDRM interfaces, each having a first connector part having a tapered projection with a non-circular external surface in a plane perpendicular to a release direction of the singular or plurality of HDRM interfaces and a central through-hole, and a second connector part having a matching formed tapered recess with a non-circular interior surface configured for form-lockingly receiving the tapered projection, for enabling transfer of at least torsion load and shear load between the first and second connector parts, when the tapered projection is inserted in the tapered recess and the first and second connector parts are pressed together, wherein the tapered projection of the first connector part has the shape of a truncated or non-truncated substantially triangular pyramid, and the tapered recess of the second connector part has the shape of a truncated or non-truncated inverse substantially triangular pyramid, wherein an exterior outline of a cross-section of the tapered projection of the first connector part, in a plane perpendicular to a release direction of the HDRM interface, has three substantially straight lateral sides with substantially equal length, and wherein also the second connector part has central through-hole;
providing a singular or plurality of release bolts and inserting a release bolt through the central through hole of the first and second connector parts of each of the singular or plurality of HDRM interfaces and clamping the first and second connector parts together by means of said release bolt to form a singular or plurality of assembled HDRM interfaces; and
attaching one of the first and second connector parts of the singular or plurality of HDRM interfaces to said adjacent structure and attaching the first spacecraft to the other of the first and second connector parts of the singular or plurality of HDRM interfaces.