Sealing system

Abstract

A projectile stage assembly for a projectile includes a projectile stage and an interstage ring. The projectile stage has an internal volume, defined by a forward wall longitudinally joined to an aft flexible sealing member by a peripheral wall. The interstage ring includes a coupling system for selectively and independently coupling the interstage ring with respect to the projectile stage and with respect to a remainder of the projectile. The flexible sealing member is fixedly and sealingly attached to an inside wall of the interstage ring, and prevents passage therethrough of fluids and / or particulates into the internal volume from an external environment outside of the projectile stage when the interstage ring is coupled to the projectile stage. The flexible sealing member is exposed to and facing the external environment at least when the projectile stage is in a precoupled configuration with respect to a remainder of the projectile.

Description

[0001] SEALING SYSTEM

[0002] TECHNOLOGICAL FIELD

[0003] The presently disclosed subject matter relates to the coupling / decoupling of two components, in particular where the two components are two respective stages of a projectile, in particular where such coupling must ensure clean conditions in at least one of the stages.

[0004] BACKGROUND

[0005] In certain types of projectiles, it is important, necessary or desirable to maintain an internal volume thereof in clean conditions, for example the payload module of a projectile, wherein a payload such as a satellite and / or other sensitive equipment may need to be stored. Such clean conditions are often important, necessary or desirable at least during assembly of the projectile and until the payload is delivered into space, to thereby prevent contamination of the satellite or other sensitive equipment in the payload module, for example.

[0006] In some such cases, the payload module needs to be assembled to a remainder of the projectile, which could include a number of stages.

[0007] In order to maintain the payload module interior clean and free of contaminants, not only must the payload module be accommodated with the satellite and / or other sensitive equipment under the clean conditions, also the assembly of payload module with respect to the remainder of the projectile, or to at least to the respective adjacent stage of the projectile, must also be carried out in clean conditions, provided by a clean room vehicle assembly building or the like.

[0008] 03043355\8-ll GENERAL DESCRIPTION

[0009] According to a first aspect of the presently disclosed subject matter there is provided a stage assembly for a projectile, the stage assembly comprising a projectile stage and an interstage ring, the projectile stage comprising an internal volume, defined by a forward wall and an aft flexible sealing member, longitudinally spaced from one another, and a peripheral wall longitudinally joining the forward wall and the flexible sealing member, the interstage ring comprising a coupling system configured for selectively and independently coupling the interstage ring with respect to the projectile stage and with respect to a remainder of the projectile; the interstage ring comprising the flexible sealing member, wherein the flexible sealing member is fixedly and sealingly attached to an inside wall of the interstage ring, and wherein the sealing member is configured to prevent passage through the flexible sealing member of at least one of fluids and particulates into the internal volume from an external environment outside of the projectile stage when the interstage ring is coupled to the projectile stage; and wherein the flexible sealing member is exposed to and facing the external environment at least when the projectile stage is in a precoupled configuration with respect to a remainder of the projectile.

[0010] For example, said peripheral wall defines at least part of a peripheral wall of the projectile stage, wherein the peripheral wall has an internal wall surface facing and exposed to the internal volume, and an outer wall surface facing and exposed to the external environment.

[0011] Additionally or alternatively, for example, the forward wall is an internal wall of the projectile stage.

[0012] Additionally or alternatively, for example, the forward wall and the peripheral wall are configured to prevent passage through the forward wall and the peripheral wall, respectively, of at least one of fluids and particulates into the internal volume from the external environment outside of the projectile stage.

[0013] 03043355\8-ll Additionally or alternatively, for example, said sealing member has a first surface exposed to and facing the internal volume in the precoupled configuration, and a second surface exposed to and facing the external environment when the stage is in the precoupled configuration, and wherein the internal surface and the external surface are separated by a sealing membrane thickness.

[0014] Additionally or alternatively, for example, the sealing member is configured for deforming when subjected to at least a longitudinal force acting thereon. For example, said force is generated by a non-zero pressure difference in the internal volume in the precoupled configuration. Additionally or alternatively, for example, said force is generated by a positive pressure difference in the internal volume acting on said first surface. Additionally or alternatively, for example, said force causes an aft longitudinal displacement of at least a central portion of the sealing member; for example, said aft longitudinal displacement is about 20% with respect to a radius of the sealing member. Additionally or alternatively, for example, said force causes the aft longitudinal displacement of at least a central portion of the sealing member to an aft longitudinal position aft of an aft peripheral edge of the projectile stage. Additionally or alternatively, for example, said force causes forward longitudinal displacement of at least a central portion of the sealing member. For example, said forward longitudinal displacement is about 20% with respect to a radius of the sealing member. Additionally or alternatively, for example, said force causes the forward longitudinal displacement of at least a central portion of the sealing member to a forward longitudinal position forward of an aft peripheral edge of the projectile stage. For example, said forward longitudinal position is correlated to a forward projection of an adjacent portion of the remainder of the projectile. For example, said force is correlated to a reaction force generated responsive to abutment of the forward projection onto the sealing member. For example, said force is generated responsive to abutment of the second surface of the sealing member on the projection of the adjacent portion of the remainder of the projectile.

[0015] For example, said pressure difference corresponds to a pressure in the external environment being nominally zero.

[0016] 03043355\8-ll Additionally or alternatively, for example, the sealing member comprises a base ring radially connected to a disc center plate via an intermediate ring. For example, said base ring is configured for being sealably affixed to the inside wall of the interstage ring.

[0017] Additionally or alternatively, for example, said base ring, said intermediate ring and said disc center plate are contiguous with one another and form a barrier that is configured for preventing flow therethrough, at least in a direction into the internal volume from the external environment, of at least one of the fluids and particulates, in the precoupled configuration. For example, the fluids include any one or more of gasses and liquids, and wherein the particulates include particulate matter, including one or more of debris, atmospherically carried solid contaminates including one or more of debris, sand, ash, hail.

[0018] Additionally or alternatively, for example, said thickness is uniform throughout the sealing member. Alternatively, said thickness is non uniform, being greatest at the base ring and tapering to a minimum said thickness at the disc center plate. Alternatively, each one of the base ring, intermediate ring and said disc center plate have respective thickness that are uniform or non-uniform.

[0019] Additionally or alternatively, for example, the second surface is coextensive with at least part of the base ring, all of the intermediate ring and all of the disc center plate on one longitudinal side of the sealing membrane, and wherein the first surface is coextensive with at least part of the base ring, all of the intermediate ring and all of the disc center plate on the other longitudinal side of the sealing membrane.

[0020] Additionally or alternatively, for example, the disc center plate extends radially from a center of the sealing member by a first radius, wherein the intermediate ring extends radially away from the center from the first radius to a second radius, and wherein the base ring extends radially away from the center from the second radius to a third radius. For example, said third radius corresponds to an internal radius of the inside wall of the interstage ring. Additionally or alternatively, for example, the first radius is about 20% of the second radius, and wherein the second radius is about 90% of the third radius; alternatively for example, the first radius is zero, and / or, the second radius is in the range between about 50% and about 90% of the third radius.

[0021] 03043355\8-ll Additionally or alternatively, for example, said base ring, said intermediate ring, and said disc center plate have different flexibilities with respect to one another. For example, said base ring and the disc center plate are relatively inflexible, and wherein said intermediate ring provides at least a majority of the flexibility for the sealing ring.

[0022] Additionally or alternatively, for example, each one of a first area of said external surface and a second area of said internal surface are nominally constant, irrespective of whether or not said force is acting on the sealing membrane.

[0023] Additionally or alternatively, for example, said sealing member is made from a material that provides plastic or elastic deformation when subjected to said force.

[0024] Additionally or alternatively, for example, the sealing member is made from flexible material, optionally including glass fiber panels embedded in a silicone matrix.

[0025] Additionally or alternatively, for example, when the stage is coupled with respect to the remainder of the projectile the sealing member adopts a generally concave configuration, and, wherein when the stage is decoupled with respect to the remainder of the projectile the sealing member adopts a generally convex configuration.

[0026] Additionally or alternatively, for example, said coupling system comprises a first coupling arrangement configured for selectively coupling the interstage ring with respect to the remainder of the projectile, and a second coupling arrangement configured for selectively coupling the interstage ring with respect to projectile stage.

[0027] For example, the first coupling arrangement is configured for reversibly coupling the interstage ring with respect to the remainder of the projectile once the projectile stage is coupled to the remainder of the projectile in a coupled configuration, and wherein the second coupling arrangement is also configured for reversibly coupling the interstage ring with respect to the projectile stage. For example, the second coupling arrangement is configured for selectively coupling the interstage ring with respect to the projectile stage in the precoupled configuration and in the coupled configuration, and wherein the second coupling arrangement is further configured for selectively decoupling the interstage ring with respect to the projectile stage and optionally for selectively decoupling the interstage ring with respect to the remainder of the projectile in a decoupled configuration, for example following the coupled configuration.

[0028] 03043355\8-ll For example, the first coupling arrangement is configured for permanently coupling the interstage ring with respect to the remainder of the projectile once the projectile stage is coupled to the remainder of the projectile in a coupled configuration, and wherein the second coupling arrangement is configured for reversibly coupling the interstage ring with respect to the projectile stage. For example, the second coupling arrangement is configured for selectively coupling the interstage ring with respect to the projectile stage in the precoupled configuration and in the coupled configuration, and wherein the second coupling arrangement is further configured for selectively decoupling the interstage ring with respect to the projectile stage in a decoupled configuration, following the coupled configuration.

[0029] Alternatively, for example, the second coupling arrangement is configured for permanently coupling the interstage ring with respect to projectile stage, and wherein the first coupling arrangement is configured for reversibly coupling the interstage ring with respect to the remainder of the proj ectile once the proj ectile stage is coupled to the remainder of the projectile in a coupled configuration. For example, the first coupling arrangement is configured for selectively coupling the interstage ring with respect to the remainder of the projectile in the coupled configuration, and wherein the first coupling arrangement is further configured for selectively decoupling the interstage ring with respect to the remainder of the projectile in a decoupled configuration, following the coupled configuration.

[0030] Additionally or alternatively, for example, the projectile stage is integrally formed with the interstage ring, and wherein said coupling system comprises a first coupling arrangement configured for selectively and reversibly coupling the interstage ring with respect to the remainder of the projectile.

[0031] According to a second aspect of the presently disclosed subject matter there is provided a projectile comprising the projectile stage assembly as defined herein regarding the first aspect of the presently disclosed subject matter, and further comprising an adjacent additional stage of the projectile detachably coupled with respect to the projectile stage assembly via said coupling arrangement.

[0032] According to a third aspect of the presently disclosed subject matter there is provided a projectile comprising a first stage, a second stage, and an interstage ring, wherein:

[0033] 03043355\8-ll the interstage ring comprising a flexible sealing member configured to prevent passage through the flexible sealing member of at least one of fluids and particulates; the interstage ring comprises a coupling system configured for selectively coupling the interstage ring and the second stage with respect to one another, and for independently and selectively coupling the interstage ring and the first stage with respect to one another; the second stage comprises an internal volume, sealed at the aft end by the flexible sealing member, when the second stage is coupled with respect to the interstage ring via the coupling system; wherein the interstage ring and second stage are coupled with respect to one another via the coupling system to provide a stage assembly in a precoupled configuration.

[0034] For example, said coupling system comprises a first coupling arrangement configured for selectively coupling the interstage ring with respect to the first stage, and a second coupling arrangement configured for selectively coupling the interstage ring with respect to second stage.

[0035] For example, the first coupling arrangement is configured for reversibly coupling the interstage ring with respect to the first stage once the second stage is coupled to the first stage in a coupled configuration, and wherein the second coupling arrangement is also configured for reversibly coupling the interstage ring with respect to the second stage. For example, the second coupling arrangement is configured for selectively coupling the interstage ring with respect to the second stage in the precoupled configuration and in the coupled configuration, and wherein the second coupling arrangement is further configured for selectively decoupling the interstage ring with respect to the second stage and optionally for selectively decoupling the interstage ring with respect to the first stage in a decoupled configuration, for example following the coupled configuration.

[0036] For example, the first coupling arrangement is configured for permanently coupling the interstage ring with respect to the first stage once the second stage is coupled to the first stage in a coupled configuration, and wherein the second coupling arrangement is configured for reversibly coupling the interstage ring with respect to the second stage. For example, the second coupling arrangement is configured for selectively coupling the interstage ring with

[0037] 03043355\8-ll respect to the second stage in the precoupled configuration and in the coupled configuration, and wherein the second coupling arrangement is further configured for selectively decoupling the interstage ring with respect to the second stage in a decoupled configuration, following the coupled configuration.

[0038] Alternatively, for example, the second coupling arrangement is configured for permanently coupling the interstage ring with respect to second stage, and wherein the first coupling arrangement is configured for reversibly coupling the interstage ring with respect to the first stage once the projectile stage is coupled to the first stage in a coupled configuration. For example, the first coupling arrangement is configured for selectively coupling the interstage ring with respect to the first stage in the coupled configuration, and wherein the first coupling arrangement is further configured for selectively decoupling the interstage ring with respect to the first stage in a decoupled configuration, following the coupled configuration.

[0039] Alternatively, for example, the second stage is integrally formed with the interstage ring, and wherein said coupling system comprises a first coupling arrangement configured for selectively and reversibly coupling the interstage ring with respect to the first stage.

[0040] Additionally or alternatively, for example, the first stage comprises a forward projecting structure configured for projecting into an aft end of the second stage in the coupled configuration, and wherein: the flexible sealing member being exposed to and facing the external environment at least in the precoupled configuration; and the flexible sealing member being in abutting contact with the projecting member in the coupled configuration.

[0041] For example, the forward projecting structure longitudinally projects forward of a forward peripheral edge by a spacing. For example, said spacing, as a percentage of an outer diameter of said forward peripheral edge, is in a range between 20% and 80%, or in a range between 30% and 70%, or in a range between 40% and 60%, or in a range between 30% and 50%.

[0042] Additionally or alternatively, for example, the forward projecting structure is any one of hemispherical and frusto-conical.

[0043] 03043355\8-ll Additionally or alternatively, for example, the sealing member is longitudinally positioned with respect to the aft end of the second stage such that in the coupled configuration the forward projecting structure presses the sealing member in a forward direction to adopt a concave configuration.

[0044] Additionally or alternatively, for example, in the decoupled configuration, the sealing member is in any one of a convex configuration and a neutral configuration.

[0045] Additionally or alternatively, for example, the projectile is a two-stage projectile.

[0046] Alternatively, for example, the projectile is a multi-stage projectile having more than two stages, wherein the second stage and the first stage correspond to an uppermost stage and to a penultimate stage, respectively, of the projectile.

[0047] Alternatively, for example, the projectile is a multi-stage projectile having more than two stages, wherein the second stage and the first stage correspond to two serially adjacent stages, respectively, of the projectile.

[0048] Alternatively, for example, the second stage and the first stage correspond to the payload and to an uppermost stage, respectively, of the projectile.

[0049] According to a fourth aspect of the presently disclosed subject matter there is provided a stage for a projectile, the stage being detachably coupleable to a remainder of the projectile via a coupling arrangement, the stage comprising an internal volume, defined by a forward wall and an aft flexible sealing member, longitudinally spaced from one another, and a peripheral wall longitudinally joining the forward wall and the flexible sealing member, wherein the flexible sealing member is fixedly and sealingly attached to the peripheral wall and is configured to prevent passage through the flexible sealing member of at least one of fluids and particulates into the internal volume from an external environment outside of the stage; and wherein the flexible sealing member is exposed to and facing the external environment when the stage is decoupled with respect to a remainder of the projectile.

[0050] 03043355\8-ll For example, said peripheral wall defines at least part of a peripheral wall of the stage, wherein the peripheral wall has an internal wall surface facing and exposed to the internal volume, and an outer wall surface facing and exposed to the external environment.

[0051] Additionally or alternatively, for example, the forward wall is an internal wall of the stage.

[0052] Additionally or alternatively, for example, the forward wall and the peripheral wall are configured to prevent passage through the forward wall and the peripheral wall, respectively, of at least one of fluids and particulates into the internal volume from the external environment outside of the stage.

[0053] Additionally or alternatively, for example, said sealing member has an internal surface exposed to and facing the internal volume, and an external surface exposed to and facing the external environment when the stage is decoupled with respect to a remainder of the projectile, and wherein the internal surface and the external surface are separated by a sealing membrane thickness.

[0054] Additionally or alternatively, for example, the sealing member is configured for deforming when subjected to at least a longitudinal force acting thereon. For example, said force is generated by a non-zero pressure difference in the internal volume. Additionally or alternatively, for example, said force is generated by a positive pressure difference in the internal volume acting on said internal surface. Additionally or alternatively, for example, said force causes an aft longitudinal displacement of at least a central portion of the sealing member. For example, said aft longitudinal displacement is about20% with respect to a radius of the sealing member. Additionally or alternatively, for example, said force causes the aft longitudinal displacement of at least a central portion of the sealing member to an aft longitudinal position aft of an aft peripheral edge of the stage.

[0055] Additionally or alternatively, for example, said force causes forward longitudinal displacement of at least a central portion of the sealing member. For example, said forward longitudinal displacement is about 20% with respect to a radius of the sealing member. Additionally or alternatively, for example, said force causes the forward

[0056] 03043355\8-ll longitudinal displacement of at least a central portion of the sealing member to a forward longitudinal position forward of an aft peripheral edge of the stage. For example, said forward longitudinal position is correlated to a forward projection of an adjacent portion of the remainder of the projectile. For example, said force is correlated to a reaction force generated responsive to abutment of the forward projection onto the sealing member. For example, said force is generated responsive to abutment of the external surface of the sealing member on the projection of the adjacent portion of the remainder of the projectile.

[0057] Additionally or alternatively, for example, the sealing member comprises a base ring radially connected to a disc center plate via an intermediate ring. For example, the base ring is configured for being sealably affixed to an inside surface of an aft end of the stage. Additionally or alternatively, for example, said base ring, said intermediate ring and said disc center plate are contiguous with one another and form a barrier that is configured for preventing flow therethrough, at least in a direction into the internal volume from the external environment, of at least one of the fluids and particulates. For example, the fluids include any one or more of gasses and liquids, and wherein the particulates include particulate matter, including one or more of debris, atmospherically carried solid contaminates including one or more of debris, sand ash, hail.

[0058] Additionally or alternatively, for example, said thickness is uniform throughout the sealing member. Alternatively, for example, said thickness is non uniform, being greatest at the base ring and tapering to a minimum said thickness at the disc center plate. Alternatively, for example, each one of the base ring, intermediate ring and said disc center plate have respective thickness that are uniform or non-uniform.

[0059] Additionally or alternatively, for example, the external surface is coextensive with at least part of the base ring, all of the intermediate ring and all of the disc center plate on one longitudinal side of the sealing membrane, and wherein the internal surface is coextensive with at least part of the base ring, all of the intermediate ring and all of the disc center plate on the other longitudinal side of the sealing membrane.

[0060] Additionally or alternatively, for example, the disc center plate extends radially from a center of the sealing member by a first radius, wherein the intermediate ring extends radially away from the center from the first radius to a second radius, and wherein the base 03043355\8-ll ring extends radially away from the center from the second radius to a third radius. For example, said third radius corresponds to an internal radius of an inside surface of the stage. Additionally or alternatively, for example, the first radius is about 20% of the second radius, and wherein the second radius is about 90% of the third radius, or, the first radius is zero, and / or, the second radius is in the range between about 50% and about 90% of the third radius.

[0061] Additionally or alternatively, for example, said base ring, said intermediate ring, and said disc center plate have different flexibilities with respect to one another. For example, said base ring and the disc center plate are relatively inflexible, and wherein said intermediate ring provides at least a majority of the flexibility for the sealing ring.

[0062] Additionally or alternatively, for example, each one of a first wetted or longitudinally projected area of said external surface and a second wetted or longitudinally projected area of said internal surface are nominally constant, irrespective of whether or not said force is acting on the sealing membrane.

[0063] Additionally or alternatively, for example, said sealing member is made from a material that provides plastic or elastic deformation when subjected to said force.

[0064] Additionally or alternatively, for example, the sealing member is made from flexible material, optionally including glass fiber panels embedded in a silicone matrix.

[0065] Additionally or alternatively, for example, when the stage is coupled with respect to the remainder of the projectile the sealing member adopts a generally concave configuration, and, wherein when the stage is decoupled with respect to the remainder of the projectile the sealing member adopts a generally convex configuration.

[0066] According to a fifth aspect of the presently disclosed subject matter there is provided a projectile comprising the stage as defined herein regarding the fourth aspect of the presently disclosed subject matter, and further comprising an adjacent additional stage detachably coupled with respect to the stage via said coupling arrangement.

[0067] According to a sixth aspect of the presently disclosed subject matter there is provided a projectile comprising a first stage a second stage, and a coupling arrangement, wherein:

[0068] 03043355\8-ll the coupling arrangement is configured for releasably coupling the first stage and the second stage with respect to one another, between a coupled configuration and a decoupled configuration; the first stage comprises a forward projecting structure configured for projecting into an aft end of the second stage in the coupled configuration; the second stage comprises an internal volume, sealed at the aft end by a flexible sealing member, wherein the flexible sealing member is configured to prevent passage through the flexible sealing member of at least one of fluids and particulates into the internal volume from an external environment outside of the second stage in the decoupled configuration; the flexible sealing member being exposed to and facing the external environment in the decoupled configuration; and the flexible sealing member being in abutting contact with the projecting member in the coupled configuration.

[0069] For example, the forward projecting structure longitudinally projects forward of a forward peripheral edge by a spacing. For example, said spacing, as a percentage of an outer diameter of said forward peripheral edge, is in a range between 20% and 80%, or in a range between 30% and 70%, or in a range between 40% and 60%, or in a range between 30% and 50%.

[0070] Additionally or alternatively, for example, the forward projecting structure is any one of hemispherical and frusto-conical.

[0071] Additionally or alternatively, for example, the sealing member is longitudinally positioned with respect to the aft end of the second stage such that in the coupled configuration the forward projecting structure presses the sealing member in a forward direction to adopt a concave configuration.

[0072] Additionally or alternatively, for example, in the decoupled configuration, the sealing member is in any one of a convex configuration and a neutral configuration.

[0073] Additionally or alternatively, for example, the projectile is a two-stage projectile, or, the projectile is a multi-stage projectile having more than two stages, wherein the second stage and the first stage correspond to an uppermost stage and to a penultimate

[0074] 03043355\8-ll stage, respectively, of the projectile, or, the projectile is a multi-stage projectile having more than two stages, wherein the second stage and the first stage correspond to two serially adjacent stages, respectively, of the projectile, or, the second stage and the first stage correspond to the payload and to an uppermost stage, respectively, of the projectile.

[0075] Additionally or alternatively, for example, the second stage is the stage as defined herein regarding the fourth aspect of the presently disclosed subject matter.

[0076] According to a seventh aspect of the presently disclosed subject matter there is provided an interstage ring for a projectile, the projectile comprising a first stage and a second stage sandwiching therebetween the interstage ring, wherein: the interstage ring comprising a flexible sealing member configured to prevent passage through the flexible sealing member of at least one of fluids and particulates; the interstage ring comprises a coupling system configured for selectively coupling the interstage ring and the second stage with respect to one another, and for independently and selectively coupling the interstage ring and the first stage with respect to one another; the second stage comprises an internal volume, sealable at the aft end by the flexible sealing member, when the second stage is coupled with respect to the interstage ring via the coupling system.

[0077] For example, said coupling system comprises a first coupling arrangement configured for selectively coupling the interstage ring with respect to the first stage, and a second coupling arrangement configured for selectively coupling the interstage ring with respect to second stage.

[0078] For example, the first coupling arrangement is configured for reversibly coupling the interstage ring with respect to the first stage once the second stage is coupled to the first stage in a coupled configuration, and wherein the second coupling arrangement is also configured for reversibly coupling the interstage ring with respect to the second stage. For example, the second coupling arrangement is configured for selectively coupling the interstage ring with respect to the second stage in the precoupled configuration and in the coupled configuration, and wherein the second coupling arrangement is further configured for selectively decoupling the interstage ring with respect to the second stage and optionally

[0079] 03043355\8-ll for selectively decoupling the interstage ring with respect to the first stage in a decoupled configuration, for example following the coupled configuration.

[0080] Additionally or alternatively, for example, the first stage comprises a forward projecting structure configured for projecting into an aft end of the second stage in the coupled configuration, and wherein: the flexible sealing member being exposed to and facing the external environment at least in the precoupled configuration; and the flexible sealing member being in abutting contact with the projecting member in the coupled configuration.

[0081] For example, the forward projecting structure longitudinally projects forward of a forward peripheral edge by a spacing. For example, said spacing, as a percentage of an outer diameter of said forward peripheral edge, is in a range between 20% and 80%, or in a range between 30% and 70%, or in a range between 40% and 60%, or in a range between 30% and 50%.

[0082] Additionally or alternatively, for example, the forward projecting structure is any one of hemispherical and frusto-conical.

[0083] Additionally or alternatively, for example, the sealing member is longitudinally positioned with respect to the aft end of the second stage such that in the coupled configuration the forward projecting structure presses the sealing member in a forward direction to adopt a concave configuration.

[0084] Additionally or alternatively, for example, in the decoupled configuration, the sealing member is in any one of a convex configuration and a neutral configuration.

[0085] 03043355\8-ll BRIEF DESCRIPTION OF THE DRAWINGS

[0086] In order to better understand the subject matter that is disclosed herein and to exemplify how it may be carried out in practice, examples will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:

[0087] Fig. 1 schematically illustrates in partially cross-sectional side view, a vehicle according to a first example of the presently disclosed subject matter, in precoupled mode.

[0088] Fig. 2 schematically illustrates in partially cross-sectional side view, the example of Fig. 1, in coupled mode.

[0089] Fig. 3 schematically illustrates in partially cross-sectional side view, the example of Fig. 1, in decoupled mode.

[0090] Fig- 4 illustrates in isometric view, an example of sealing member of vehicle example of Fig. 1.

[0091] Fig- 5 illustrates in cross-sectional side view, the sealing member example of Fig.

[0092] 4.

[0093] DETAILED DESCRIPTION

[0094] Referring to Fig. 1, Fig. 2 and Fig. 3, a vehicle according to a first example of the presently disclosed subject matter, generally designated 10, comprises a first component 100 and a second component 200, reversibly coupled to one another via sealing system, the sealing system being in the form of an interstage ring 400 and comprising a coupling system 300.

[0095] In at least this example, and according to an aspect of the presently disclosed subject matter, such a vehicle is a projectile, which is launchable from a terrestrial platform, or from a seaborne platform, or from an airborne platform, the projectile being capable of reaching a high altitude, optionally including space, such that the second component can reach any one of suborbital flight or orbital flight or other spaceflight. Alternatively, such a projectile can comprise additional booster stages to provide at least initial take-off thrust and optionally additional boost to the projectile to enable the projectile to reach a high altitude, optionally 03043355\8-ll including space, such that the second component can reach any one of suborbital flight or orbital flight or other spaceflight.

[0096] For example, the projectile (also interchangeably referred to herein as any one of: a multi-stage projectile; launch vehicle, a launch vehicle assembly, a multi-stage launch vehicle) can be at least any one of the following: a two-stage launch vehicle;

[0097] - the two upper stages of a multi-stage launch vehicle;

[0098] - two serially adjacent intermediate stages of a multi-stage projectile; a final stage of a launch vehicle including a detachable payload.; single stage launch vehicle including a detachable payload.

[0099] In at least this example, the first component 100 and the second component 200 correspond to a first stage and a second stage, respectively, of the projectile, the projectile having two stages. However, in at least some alternative variations of this example, the second component 200 and the first component 100 correspond to the uppermost stage and to the penultimate stage, respectively, of the respective projectile, the projectile having more than two stages. In yet at least some other alternative variations of this example, the second component 200 and the first component 100 correspond to two serially adjacent stages of the respective projectile, the projectile having more than two stages. In yet at least some other alternative variations of this example, the second component 200 and the first component 100 correspond to the payload and to the uppermost stage, respectively, of the respective projectile; herein, such a payload is also referred to interchangeably herein as a stage of the projectile. Thus, the second component 200 is essentially detachably coupleable to the remainder of the projectile or vehicle 10, via the interstage ring 400 and coupling system 300.

[0100] As will become clearer herein, the vehicle 10 has a precoupled configuration PC, a coupled configuration CC and a decoupled configuration DC.

[0101] In the precoupled configuration PC, and referring to Fig. 1, the second component 200 is ready for coupling with the first component 100, but coupling has not yet taken place.

[0102] In the coupled configuration CC, and referring to Fig. 2, the second component 200 and the first component 100 are coupled to one another, having transited to the coupled

[0103] 03043355\8-ll configuration CC from the precoupled configuration PC; launch of the projectile 10 occurs only in the coupled configuration CC.

[0104] In the decoupled configuration DC, and referring to Fig. 3, the second component 200 and the first component 100 are decoupled to one another, having transited to the decoupled configuration DC from the coupled configuration CC.

[0105] Also as will become clearer herein, the coupling system 300 is configured for providing the precoupled configuration PC and the coupled configuration CC, and for selectively transitioning the projectile from the precoupled configuration PC to the coupled configuration CC, and from the coupled configuration CC to the decoupled configuration DC

[0106] In at least this example:

[0107] - the interstage ring 400 is coupled to the second component 200 in the precoupled configuration PC via the coupling system 300;

[0108] - the interstage ring 400 is coupled to the second component 200 and to the first component 100 in the coupled configuration CC via the coupling system 300;

[0109] - the interstage ring 400 is coupled to the first component 100 in the decoupled configuration DC via the coupling system 300.

[0110] In at least this example, at least the front end 110 of the first component 100 is cylindrical, and at least the aft end 220 of the second component 200 is also cylindrical, and the two components are co-axial with respect to one another and the longitudinal axis LA of the vehicle 10. In at least this example, the front end 210 of the second component 200 is ogive-shaped, or is otherwise aerodynamically contoured; however, in at least some alternative variations of this example, the respective front end of the respective second component can have any suitable shape.

[0111] While in at least this example, the interstage ring 400 is nominally annular or cylindrical having a longitudinal dimension LD (Fig. 3), in at least some alternative variations of this example the respective interstage ring can be nominally frusto-conical, for example.

[0112] 03043355\8-ll Similarly, the front end 410 of the interstage ring 400 is cylindrical, and the aft end 420 of the interstage ring 400 is also cylindrical, and the two ends are also co-axial with respect to one another and with respect to the longitudinal axis LA of the vehicle 10.

[0113] However, in at least some alternative variations of this example, the respective front end of the first component is non-cylindrical, and / or the respective aft end of the second component is non-cylindrical, and / or the front end of the interstage ring is non-cylindrical, and / or the aft end of the interstage ring is non-cylindrical, for example each can be conical, or tapering, or having a polygonal cross-section, or elliptical cross-section, or superelliptical cross-section, or any other suitable cross-section.

[0114] In any case, the front end 110 of the first component 100 and the aft end 420 of the interstage ring 400 are complementary with respect to one another, or otherwise compatible with one another, for example in shape and size, such as to enable the first component 100 and the interstage ring 400 to be coupled to one another via the coupling system 300. Similarly, the front end 410 of the interstage ring 400 and the aft end 220 of the second component 200 are complementary with respect to one another, or otherwise compatible with one another, for example in shape and size, such as to enable the second component 200 and the interstage ring 400 to be coupled to one another via the coupling system 300.

[0115] Thus, the first component 100 comprises a forward peripheral edge 190 at the forward end 110 that abuts an aft peripheral edge 490 at the aft end 420 of the interstage ring 400 in the coupled configuration CC. In at least this example, the forward peripheral edge 190 at the forward end 110 remains abutted to the aft peripheral edge 490 at the aft end 420 of the interstage ring 400 in the decoupled configuration DC.

[0116] In at least this example, the coupling system 300 comprises a first coupling arrangement 310 and a second coupling arrangement 320.

[0117] In at least this example, the first coupling arrangement 310 can include any suitable coupling arrangement suitable for coupling the first component 100 and the interstage ring 400 with respect to one another, in the coupled configuration CC and in the decoupled configuration DC. The second coupling arrangement 320 can include any suitable coupling arrangement suitable for coupling the second component 200 and the interstage ring 400 with respect to one another in the coupled configuration CC and in the precoupled

[0118] 03043355\8-ll configuration PC, and for selectively decoupling the second component 200 and the interstage ring 400 with respect to one another in the decoupled configuration DC.

[0119] Thus, the interstage ring 400 and the coupling system 300 enables transmission of all the static loads, dynamic loads, aerodynamic loads, and thermal loads between the first component 100 and the second component 200 that are expected while coupled together in the coupled configuration CC according to the specific flight plan, and up to, responsive to suitable criteria, the coupling system 300 (in particular the second coupling arrangement 320) causes the first component 100 and the second component 200 to become uncoupled with respect to one another in the decoupled configuration DC, while maintain the interstage ring 400 coupled to the first component 100. Such criteria can include, for example, one or more of elapsed time from take-off; reaching a predetermined altitude; propellants being expended in the first component; and so on.

[0120] For example, such a first coupling arrangement 310 can include any conventional clamping or fastening arrangement, for example bolts that mechanically bolt together an aft flange 425 of the interstage ring 400 and a forward flange 115 of the first component 100.

[0121] For example, such a second coupling arrangement 320 can include a plurality of pyrotechnic bolts or their equivalents that reversibly bolt together an aft flange 225 of the second component 200 and a forward flange 415 of the interstage ring 400. The pyrotechnic bolts can be operatively coupled to a suitable controller that is operative to cause the pyrotechnic bolts to activate and thus decouple the interstage ring 400 (together with the first component 100) and the second component 200 from one another to provide the decoupled configuration DC. Alternatively, the second coupling arrangement 320 comprises reversible mechanical coupling clamps or their equivalents for reversibly coupling the second component 200 the interstage ring 400 with respect to one another. For example the second coupling arrangement 320 comprises a connection system as disclosed in WO 2022 / 269597 mutatis mutandis, assigned to the present assignee, and the contents of which, in particular pages 12 to 29 and Figs. 1(a) to 8(d) thereof, are incorporated herein. Alternatively, for example the second coupling arrangement 320 comprises a clamp band system as disclosed in WO 2024 / 142046 mutatis mutandis, assigned to the present assignee, and the contents of which, in particular pages 11 to 30 and Figs. 1 to 10 thereof, are incorporated herein.

[0122] 03043355\8-ll In at least some alternative variations of this example, the respective first coupling arrangement 310 can include any suitable coupling arrangement suitable for coupling the first component 100 and the interstage ring 400 with respect to one another, in the coupled configuration CC and in the decoupled configuration DC, and for selectively decoupling the first component 100 and the interstage ring 400 with respect to one another in the decoupled configuration DC. In at least some such examples the respective second coupling arrangement 320 includes any suitable coupling arrangement suitable for coupling the second component 200 and the interstage ring 400 with respect to one another in the coupled configuration CC and in the precoupled configuration PC, and for selectively decoupling the second component 200 and the interstage ring 400 with respect to one another in the decoupled configuration DC. In such examples, the respective interstage ring 400 is thus reversibly coupleable with respect to the respective first component 100 via the respective first coupling arrangement 310, and, the respective interstage ring 400 is also reversibly coupleable with respect to the respective second component 200 via the respective second coupling arrangement 320. In such cases, the respective projectile can transition from the coupled configuration CC to the decoupled configuration DC by any one of the following steps: causing the respective first coupling arrangement 310 to decouple the first component 100 from the interstage ring 400, while retaining the interstage ring 400 coupled to the second component 200 via the respective second coupling arrangement 320; causing the respective second coupling arrangement 320 to decouple the second component 200 from the interstage ring 400, while retaining the interstage ring 400 coupled to the first component 100 via the respective first coupling arrangement 310; causing the respective first coupling arrangement 310 to decouple the first component 100 from the interstage ring 400, and causing the respective second coupling arrangement 320 to decouple the second component 200 from the interstage ring 400.

[0123] In the third option, decoupling of the respective first component 100 and decoupling of the second component 200 with respect to the interstage ring 400 can be concurrent, or 03043355\8-ll can occur in any order. For example, in the respective decoupled configuration DC, the respective first component 100 is first decoupled with respect to the interstage ring 400 via the respective first coupling arrangement 310, and this is followed some time later with decoupling of the second component 200 with respect to the interstage ring 400 via the respective second coupling arrangement 320. Alternatively for example, in the respective decoupled configuration DC, the second component 200 is first decoupled with respect to the interstage ring 400 via the respective second coupling arrangement 320, and this is followed some time later with decoupling of the respective first component 100 with respect to the interstage ring 400 via the respective first coupling arrangement 310. In any case, the ability for the respective interstage ring to be selectively and independently decoupled with respect to respective first component 100 and / or with respect to the respective second component 200, selectively enables the interstage ring 400 to be jettisoned independently of the first component 100 and of the second component 200, and for decoupling the interstage ring 400 from the first component 100 but while still coupled to the second component 200, to provide a two-plane separation. Such a two-plane separation may be required or desired, for example for safety reasons for example if decoupling occurs at a lower altitude than is optimal for the interstage ring 400 to be decoupled from the second component 200.

[0124] According to an aspect of the presently disclosed subject matter, the aft end 220 of the second component 200 defines an internal volume V. The volume V is bound circumferentially by the peripheral wall 230 (also interchangeably referred to herein as the inner wall) of the aft end 220, and at the forward longitudinal end by a forward wall 240. The volume V thus projects forwardly into the aft end 220 up to the forward wall 240. In at least this example, forward wall 240 is an internal wall of the second component 200, for example in the form of a bulkhead. However, in at least some alternative variations of this example, the forward wall is an external wall of the respective second component. For example, the peripheral wall 230 and the forward wall 240 together provide a fairing that internally defines the internal volume V.

[0125] The inner wall 230 and the forward wall 240 are configured to prevent any ingress therethrough of fluid and / or particulates, such as for example particulate matter, from the external environment EN and into the volume V, and optionally to prevent any fluid communication therethrough between the volume V and the external environment EN. Such fluids can include gases and / or liquids, for example atmospheric air and / or water vapor. Such 03043355\8-ll particulates can include particulate matter, such as for example debris, atmospherically carried solid contaminates including for example one or more of debris, sand, ash, hail, and so on.

[0126] The peripheral wall 230 defines part of the outer peripheral wall of the second component 200., for example part of the outer skin of the vehicle 10. The peripheral wall 230 has an internal wall surface 232 facing and exposed to the internal volume V, and an outer wall surface 234 facing and exposed to the external environment EN.

[0127] According to this aspect of the presently disclosed subject matter, the volume V can optionally accommodate a payload, including for example equipment and / or cargo, for example one or more satellites and / or sensitive equipment, and in any case it is desired or required for the volume V not to be exposed to the external environment EN. In particular it is desired or required for the volume V not to be in fluid communication with respect to the external environment EN, and at least to prevent any fluid ingress and / or particulate ingress into the volume V from the external environment EN, in particular during assembly of the second component 200 with respect to the first component 100, and until well after launch, for example until the payload can be exposed to the vacuum of space where no contaminants are expected to be present.

[0128] According to this aspect of the presently disclosed subject matter, the volume V is hermetically sealed from the outside environment EN via sealing member 500 at or near the aft end 220 of the second component 200. The provision of the sealing member 500 enables assembly of the second component 200 with respect to the first component 100, under conditions which are not required to be clean room conditions, while on the other hand ensuring that the volume V remains devoid of possible contaminants during and after such assembly. The provision of the sealing member 500 via the interstage ring 400 essentially thereby provides a sealing system for at least the second component 200.

[0129] In at least this example, the sealing member 500 is sealingly mounted to the interstage ring 400.

[0130] In at least this example, the sealing member 500 is in the form of a flexible membrane, and is thus configured at least to prevent fluid and / or particulate ingress therethrough into the volume V from the external environment EN, in the precoupled

[0131] 03043355\8-ll configuration PC and in the coupled configuration CC. While in at least this example, the sealing member 500 is also configured to prevent fluid and / or particulate communication therethrough between the volume V and the external environment EN at least in the precoupled configuration PC and in the coupled configuration CC, in at least some alternative variations of this example the respective sealing member is further configured to permit fluid egress from the volume V to the external environment EN, and for example includes vents or the like coupled to one-way valves that allow fluid flow only from the volume V to the external environment EN but not fluid flow or particulate flow from the external environment EN into volume V at least in in the precoupled configuration PC and in the coupled configuration CC. In yet other alternative variations of these examples, the respective inner wall of the respective aft end can similarly be configured to permit fluid egress of fluids from the volume V to the external environment EN but no corresponding ingress of fluids or particulates, and for example includes vents or the like coupled to oneway valves (for example flap valves) that allow fluid flow only from the volume V to the external environment EN but not from the external environment EN to volume V at least in the precoupled configuration PC and in the coupled configuration CC.

[0132] As will become clearer herein, the sealing member 500 is deformably flexible such that for example when the second component 200 is coupled with respect to the first component 100 (i.e., to the remainder of the vehicle 10) in the coupled configuration CC or in the decoupled configuration DC the sealing member 500 adopts a generally concave configuration, and, such that when the second component 200 and the first component 100 are in the precoupled configuration PC the sealing member 500 adopts a generally convex configuration.

[0133] In at least this example, the sealing member 500 is made from a flexible material that can be significantly deformed in shape, reversibly, responsive to the application of a force F thereon, in particular a longitudinal force. As will become clearer herein, such a force F can be generated by a non-zero pressure difference AP (for example a positive pressure difference or a negative pressure difference) acting on one side of the sealing member 500, or such a force can be a mechanical force applied to the other side of the sealing member 500. Furthermore, the sealing member 500 is configured for maintaining mechanical integrity, and thus not rupturing or tearing or otherwise becoming damaged, at

[0134] 03043355\8-ll least when subjected to such pressure differences AP that are within a design pressure difference APD.

[0135] Such a pressure difference AP is defined herein as the pressure difference between a first pressure Pl in the volume V, and a second pressure P2 corresponding to the external environment EN, i.e.:

[0136] AP = P1 - P2

[0137] The first pressure Pl is typically the air pressure present when installing the sealing member 500 with respect to the second component 200, i.e. via the interstage ring 400, to provide the precoupled configuration PC. For example, the first pressure Pl can be atmospheric pressure at sea level. Optionally, for example, the volume V can be at least partially evacuated after installation of the sealing member 500 with respect to the second component 200, and thus the first pressure Pl can be less than sea level atmospheric pressure.

[0138] The second pressure P2 is the ambient pressure of the external environment EN. Thus in at least some examples, at sea level, for example at or before launch of the projectile 10, the first pressure Pl and the second pressure P2 can be nominally equal to one another, and the pressure difference AP, and thus the force F, are nominally zero; alternatively, if the volume V was partially evacuated after installation of the sealing member 500, the pressure difference AP can be negative, generating the force F towards the volume V.

[0139] Typically after launch, and as the projectile gains altitude, the second pressure P2 continuously decreases, while the first pressure Pl (in at least this example) remains constant, and thus the pressure difference AP and thus the force F both correspondingly increase.

[0140] For example, the design pressure difference APD is typically the maximum pressure difference AP (plus typically a safety factor, for example +20%) that is expected to be applied to the sealing member 500 during the working life thereof. In at least this example, the first pressure Pl can be for example sea level atmospheric pressure, and the minimum magnitude for the second pressure P2 can be nominally zero, for example for applications in which the second component 200 reaches the vacuum of space. In such an example, the maximum pressure difference AP expected to be applied to the sealing member 500 is thus 03043355\8-ll 1 atmosphere (1.01325 bar; 101.325 kilopascals), and for example the design pressure difference APD can also be 1 atmosphere, or, if a safety factor of 20% is to be applied, 1.2 atmospheres (1.2159 bar; 121.59 kilopascals).

[0141] Referring also to Fig. 4 and Fig. 5, the sealing member 500 has a first surface 510 on one longitudinal side thereof, and a second surface 520 on a second longitudinal side thereof, wherein the first surface 510 and the second surface 520 are separated from one another by the sealing member thickness t.

[0142] The first surface 510 (also interchangeably referred to here as the internal surface of the sealing member 500) is exposed to and faces towards the volume V in the precoupled configuration PC and in the coupled configuration CC, and defines a first area Al that can be acted upon by the pressure difference AP to thereby generate a first force Fl acting on the first surface 510. The first surface 510 is exposed to the external environment EN when the first component 100 and the second component 200 are decoupled with respect to one another in the decoupled configuration DC.

[0143] The second surface 520 (also interchangeably referred to here as the external surface of the sealing member 500) faces away from the volume V and is exposed to the external environment EN in the precoupled configuration PC. Thus, the second surface 520 is exposed to and facing a portion of the inside of the first component 100 when the first component 100 and the second component 200 are in the coupled configuration CC or in the decoupled configuration DC.

[0144] The sealing member 500 in at least this example has a generally disc-like shape, having a circular periphery complementary to and compatible with the inner form of the inside surface 430 of the interstage ring 400. The sealing member 500 has a base ring 530 radially connected to a disc center plate 550 via an intermediate ring 540. In at least this example, the sealing member 500 is non-flat and flexible, and under all conditions of pressure difference from zero to the design pressure difference APD all parts of the sealing member 500 are never concurrently at the same longitudinal position along the longitudinal axis LA. Thus, and as will become clearer herein, in at least this example the generally disclike shape is also non-flat, and can be convex or concave for example, generally depending on conditions such as for example the magnitude and sign (i.e., whether positive or negative)

[0145] 03043355\8-ll of the pressure difference AP, and / or, whether the first component 100 and the second component 200 are precoupled, coupled or uncoupled with respect to one another.

[0146] The base ring 530 is configured for being sealably affixed to the inside surface 430 of the interstage ring 400, for example to an annular flange 435 provided thereat.

[0147] The base ring 530, intermediate ring 540 and the disc center plate 550 are contiguous with one another and form a barrier that is configured for preventing flow therethrough, at least in a direction into the volume V from the external environment EN, of fluids such as for example gasses and liquids (including for example atmospheric air and / or water vapor), and / or of particulates including for example particulate matter, such as for example debris, atmospherically carried solid contaminates including for example one or more of debris, sand, ash, hail, and so on.

[0148] While in at least some examples the thickness t can be uniform throughout the sealing member 500, in at least this example the respective thickness t is non uniform, being greatest at the base ring 530 and tapering to a minimum thickness at the disc center plate 550. Alternatively, for example, each one of the base ring 530, intermediate ring 540 and said disc center plate 550 have respective thickness that are uniform or non-uniform.

[0149] The first surface 510 is thus coextensive with at least part of the base ring 530, all of the intermediate ring 540 and all of the disc center plate 550 on one longitudinal side of the sealing membrane 500, while the second surface 520 is coextensive with at least part of the base ring 530, all of the intermediate ring 540 and all of the disc center plate 550 on the other longitudinal side of the sealing membrane 500.

[0150] Thus, the first area Al is defined as the wetted area of the first surface 510, and thus the wetted area defined by at least part of the base ring 530, all of the intermediate ring 540 and all of the disc center plate 550 on one longitudinal side of the sealing membrane 500, while the second area A2 is defined as the wetted area of the second surface 520, and thus the wetted area of at least part of the base ring 530, all of the intermediate ring 540 and all of the disc center plate 550 on the other longitudinal side of the sealing membrane 500.

[0151] Alternatively, the first area Al is defined as the longitudinally projected area of the first surface 510 (i.e., projected in the longitudinal direction), and thus the longitudinally projected area defined by at least part of the base ring 530, all of the intermediate ring 540 03043355\8-ll and all of the disc center plate 550 on one longitudinal side of the sealing membrane 500, while the second area A2 is defined as the longitudinally proj ected area of the second surface 520, and thus the longitudinally projected area of at least part of the base ring 530, all of the intermediate ring 540 and all of the disc center plate 550 on the other longitudinal side of the sealing membrane 500. In such a case, the corresponding force F is also in the longitudinal direction.

[0152] The disc center plate 550 extends radially from the longitudinal axis LA (i.e. from the center of the sealing member) by a first radius Rl, the intermediate ring 540 extends radially away from the longitudinal axis LA from the first radius Rl to a second radius R2, and the base ring 530 extends radially away from the longitudinal axis LA from the second radius R2 to a third radius R3. The third radius R3 can correspond to the internal radius of the inside surface 430 of the interstage ring 400, for example.

[0153] The relative sizes of the first radius Rl, the second radius R2 and the third radius R3 can vary between different alternative variations of this example. For example, the first radius Rl can be about 20% of the third radius R2 (i.e., 20%±5% of the third radius R2), while the second radius R2 can be about 90% of the third radius R3 (i.e., 90%±5% of the third radius R3). In other examples, for example, the first radius Rl can be nominally zero, and / or, the second radius R2 can be in the range between about 50% and about 90% of the third radius R3 (i.e., between 50%±5% and 90%±5% of the third radius R3).

[0154] In at least this example, the base ring 530, intermediate ring 540 and the disc center plate 550 have different flexibilities with respect to one another. For example, the base ring 530 and the disc center plate 550 can be relatively inflexible (or are at least less flexible than the intermediate ring 540), while the intermediate ring 540 provides a majority (i.e., most or all) of the required flexibility for the sealing ring 500.

[0155] By flexibility is meant herein the facility or extent by which the respective base ring 530, intermediate ring 540 and the disc center plate 550 are able to deform at least in the longitudinal direction responsive to the application of a first force Fl on the first surface 510, or responsive to a second force F2 on the second surface 520. For example, application of the first force Fl or of the second force F2 on the sealing member 500 causes an aft longitudinal displacement or a forward longitudinal displacement, respectively, of at least a

[0156] 03043355\8-ll central portion of the sealing member 500, for example of at least the disc center plate 550 and optionally also of part or all of the intermediate ring 540.

[0157] In at least some examples, the sealing member 500 is sufficiently flexible such as to essentially sit in abutment with the contour of the forward projecting structure 150.

[0158] For example when the first force Fl corresponds to the design pressure difference APD, the sealing member 500 is maximally deformed aft to a convex configuration CX, for example as illustrated in Fig. 5, in which the aft longitudinal displacement ASa of the disc center plate 550 with respect to the base ring 530 is maximized. For example, such maximal aft longitudinal displacement ASa can be in at least one the following ranges as percentages of the third radius R3: between about 10% and about 100%; between about 20% and about 90%; between about 30% and about 80%; between about 40% and about 70%.. For example, the first force Fl can cause the aft longitudinal displacement of at least a central portion of the sealing member 500 to an aft longitudinal position that is aft of the aft peripheral edge 425 of the interstage ring 400.

[0159] In at least some examples, the sealing member 500 is sufficiently flexible such as to essentially sit on the contour of the forward projecting structure 150, for example when the first component 100 and the second component 200 are being assembled together via the interstage ring 400, and also optionally during the initial stages of flight from launch and until the first component 100 and the second component 200 are decoupled with respect to one another. The flexibility of the sealing member 500 enables the tolerances and dimensions of the forward projecting structure 150 to be less accurate than that of other parts of the first component 100 or of the second component 200.

[0160] Conversely, for example, when the second force F2 corresponds to predetermined magnitude, the sealing member 500 is maximally deformed forwardly to a concave configuration CV, for example in dotted line 500' as illustrated in Fig. 5, in which the forward longitudinal displacement ASf of the disc center plate 550 with respect to the base ring 530 is maximized. As will become clearer below, such a magnitude of the second force F2 can be generated, for example, in the coupled configuration CC, wherein the first component 100 and the second component 200 are coupled with respect to one another via the interstage ring 400, and the first component 100 comprises a forward projecting structure 150 which, in the coupled configuration, projects into the aft end 220 of the second 03043355\8-ll component 200 (via the sealing member 500), as illustrated in Fig. 2, for example. For example, such maximal forward longitudinal displacement ASf can be in at least one of the following ranges as percentages of the third radius R3: between about 10% and about 100%; between about 20% and about 90%; between about 30% and about 80%; between about 40% and about 70%. For example, the second force F2 can cause the aft longitudinal displacement of at least a central portion of the sealing member 500 to a forward longitudinal position that is forward of the aft peripheral edge 225 of the second component 200. For example, the forward longitudinal position is correlated to a forward projection of an adjacent portion, for example a projecting structure 150, of the first component 100 in the coupled configuration CC, as will become clearer herein. For example, the second force F2 is correlated to a reaction force generated responsive to abutment of the forward projection onto the sealing member 500 in the coupled configuration CC or in the decoupled configuration DC; for example, the second force F2 is generated responsive to abutment of the external surface of the sealing member 500 on the projection of the adjacent portion of the remainder of the projectile, as will become clearer herein.

[0161] In at least some implementations of the above examples, the sealing member 500 has a Youngs modulus in the range between 60 GPa and 90 GPa.

[0162] In at least this example, such deformation is neither elastic not plastic, and the magnitudes of the first area Al and of the second area A2 are each nominally constant regarding of the particular state of deformation of the sealing member 500, irrespective of whether the first force Fl or the second force F2 or no force is acting on the sealing membrane 500.

[0163] However, in at least some alternative variations of this example, the respective sealing member is made from a material that provides plastic or elastic deformation when subjected to the first force Fl or the second force F2.

[0164] The sealing member 500 can be made from any suitable material that provides the above-mentioned properties, regarding preventing therethrough ingress of fluids and / or particulates, and regarding the required flexibility and deformation thereof when the first force Fl or the second force F2 are applied thereto. For example, such a material can include a plurality of glass fiber panels embedded in a matrix of silicone rubber, vulcanized rubber, any other suitable rubber, composite materials, and so on. 03043355\8-ll Referring again to Fig. 1 and Fig. 2, according to an aspect of the presently disclosed subject matter, and as disclosed above, the first component 100 comprises a forward projecting structure 150 which, in the coupled configuration CC, projects into the interstage ring 400 and in at least some examples also proj ects further into the aft end 220 of the second component 200.

[0165] Thus, the structure 150 longitudinally projects forward of the forward peripheral edge 190 at the forward end 110. For example, the structure 150 longitudinally projects forward of the forward peripheral edge 190 by a spacing M. Such a spacing M can be, as a percentage of the outer diameter D of forward end 110 at the forward peripheral edge 190, in a range, for example between 20% and 80%, or for example between 30% and 70%, or for example between 40% and 60%, or for example between 30% and 50%,

[0166] For example, the structure 150 can be hemispherical, or alternatively frusto-conical or other suitable shape.

[0167] For example, such a structure 150 can be a forward bulkhead of a propellant tank housed in the first component 100. Alternatively, such a structure 150 can be any other nominally rigid structure.

[0168] Referring again to Fig. 2 the sealing member 500 is longitudinally positioned with respect to the interstage ring 400, in particular with respect to the aft peripheral edge 490, such that in the coupled configuration CC and in the decoupled configuration DC the forward projecting structure 150 presses the sealing member 500 in a forward direction to adopt a concave configuration, thereby applying a second force F2 to the second surface 520 of the sealing member 500. In at least some alternative variations of this example, the second force F2 can be zero or close thereto, and the sealing member 500 is sufficiently flexible such that in the non-stressed condition, the sealing member 500 abuts onto the forward projecting structure 150.

[0169] In the coupled configuration CC and in the decoupled configuration DC, a majority of the second surface 520 can be in abutting contact with the outer surface 155 of the projecting structure 150, for example including any one of: just the disc center plate 550; the disc center plate 550 and part of the intermediate ring 540; the disc center plate 550 and all

[0170] 03043355\8-ll of the intermediate ring 540 but excluding the base ring 530; the disc center plate 550, all of the intermediate ring 540, and at least part of the base ring 530.

[0171] In at least some implementations of the above examples, in the respective precoupled configuration PC, the sealing member 500 can be, for example, in a neutral configuration in which the sealing member 500 is unstressed. In such a neutral configuration the sealing member 500 can adopt a non-regular transverse cross-section, for example undulated form, in which for example some parts of the intermediate ring 540 are forward of base ring 530, while other parts of the intermediate ring 540 are aft of the base ring 530, for example as illustrated at 500" in Fig. 5.

[0172] Alternatively, in the precoupled configuration PC, the sealing member 500 can be for example in a concave configuration CV similar to that as illustrated at 500' in Fig. 5 for example.

[0173] In operation, and under clean room conditions, the second component 200 is prepared and loaded with a payload, for example one or more satellites and / or sensitive equipment, for example imaging equipment or sensors, after which the volume V is sealed via the sealing member 500, still under clean room conditions, by coupling the interstage ring 400 to the second component 200 via the second coupling arrangement 320, thereby providing the precoupled configuration PC. Thereafter, the projectile stage assembly 700, comprising the assembled second component 200 and interstage ring 400 in the precoupled configuration PC, can be removed from the clean room, and assembled with respect to the first component 100 under regular, non clean room conditions, via the first coupling arrangement 310 to provide the coupled configuration CC. Alternatively, the projectile stage assembly 700 can remain in the clean room, and assembled with respect to the first component 100 also under clean room conditions, to provide the coupled configuration CC in clean room conditions.

[0174] The assembled projectile 10 can then be launched in the coupled configuration CC, and at a predetermined altitude and / or time after launch, the second component 200 is decoupled from the first component 100 to provide the decoupled configuration DC, for example by suitably actuating the second coupling arrangement 320, and the interstage ring remains coupled to the first component 100. When the second component 200 reaches a predetermined altitude, typically the vacuum of space, the volume V is exposed to the space 03043355\8-ll environment, and one or more satellites payload can be deployed from the internal volume V

[0175] In at least some alternative variations of the above examples, the respective interstage ring 400 is permanently coupled to the respective second component 200, and optionally can be integrally formed therewith. Thus in such examples the respective interstage ring 400 forms the aftmost portion of the respective second component 200.

[0176] In such examples, in the respective decoupled configuration DC (as in the respective precoupled configuration PC) the respective interstage ring 400 effectively remains coupled to the second component 200, rather than to the first component 100. In the respective coupled configuration CC the respective interstage ring 400 is also reversibly coupled to the first component 100. Thus, in such examples, the respective first coupling arrangement 310

[0177] In such examples, the respective first coupling arrangement 310 can include any suitable coupling arrangement suitable for coupling the interstage ring 400 (and thus the second component 200) and the first component 100 with respect to one another in the coupled configuration CC, and for selectively decoupling the second component 200 (via the interstage ring 400) with respect to the first component 100 in the decoupled configuration DC.

[0178] For example, in such examples, such a respective first coupling arrangement 310 can include a plurality of pyrotechnic bolts or their equivalents that reversibly bolt together a forward edge 190 of the first component 100 and an aft edge 490 of the interstage ring 400. The pyrotechnic bolts can be operatively coupled to a suitable controller that is operative to cause the pyrotechnic bolts to activate and thus decouple the interstage ring 400 (together with the second component 200) and the first component 100 from one another to provide the decoupled configuration DC. Alternatively, the first coupling arrangement 310 comprises reversible mechanical coupling clamps or their equivalents for reversibly coupling the first component 100 and the interstage ring 400 (and thus the second component 200) with respect to one another. For example the first coupling arrangement 310 comprises a connection system as disclosed in WO 2022 / 269597 mutatis mutandis, assigned to the present assignee, and the contents of which, in particular pages 12 to 29 and Figs. 1(a) to 8(d) thereof, are incorporated herein. Alternatively, for example the first coupling arrangement 310 comprises a clamp band system as disclosed in WO 2024 / 142046 mutatis 03043355\8-ll mutandis, assigned to the present assignee, and the contents of which, in particular pages 11 to 30 and Figs. 1 to 10 thereof, are incorporated herein.

[0179] On the other hand, the respective second coupling arrangement 320 (in alternative variations of these examples in which the respective interstage ring 400 is not integrally formed with the respective second component 200), the respective second coupling arrangement 320 can include any suitable coupling arrangement suitable for coupling the second component 200 and the interstage ring 400 with respect to one another, in the respective precoupled configuration PC, in the respective coupled configuration CC and in the respective decoupled configuration DC.

[0180] For example, such a respective second coupling arrangement 320 can include any conventional clamping or fastening arrangement, for example bolts that mechanically bolt together a respective forward edge 415 of the interstage ring 400 and an aft edge of the second component 200.

[0181] In the respective coupled configuration CC, a majority of the respective second surface 520 can be in abutting contact with the respective outer surface 155 of the respective projecting structure 150, for example including any one of: just the disc center plate 550; the disc center plate 550 and part of the intermediate ring 540; the disc center plate 550 and all of the intermediate ring 540 but excluding the base ring 530; the disc center plate 550, all of the intermediate ring 540, and at least part of the base ring 530.

[0182] Responsive to such abutting contact, the second force F2 can be generated as a reaction to the abutment. Furthermore, at decoupling, when the respective second surface 520 is exposed to the external environment EN, the pressure difference AP can become quickly adjusted to the conditions of the corresponding second pressure P2, thereby generating the corresponding first force Fl, which can operate to push aft the respective first component 100 with respect to the respective second component 200, and thus assist in the separation of the two components after decoupling.

[0183] It is to be noted that, in the precoupled configuration PC, the sealing member 500 can be, for example, in a convex configuration CX similar to that as illustrated in Fig. 1 or Fig. 5 for example.

[0184] 03043355\8-ll Finally, it should be noted that the word “comprising” as used throughout the appended claims is to be interpreted to mean “including but not limited to”.

[0185] While there has been shown and disclosed examples in accordance with the presently disclosed subject matter, it will be appreciated that many changes may be made therein without departing from the scope of the presently disclosed subject matter as set out in the claims.

[0186] 03043355\8-ll

Claims

CLAIMS:

1. A projectile stage assembly for a projectile, the stage assembly comprising a projectile stage and an interstage ring, the projectile stage comprising an internal volume, defined by a forward wall and an aft flexible sealing member, longitudinally spaced from one another, and a peripheral wall longitudinally joining the forward wall and the flexible sealing member; the interstage ring comprising a coupling system configured for selectively and independently coupling the interstage ring with respect to the projectile stage and with respect to a remainder of the projectile; the interstage ring comprising the flexible sealing member, wherein the flexible sealing member is fixedly and sealingly attached to an inside wall of the interstage ring, and wherein the sealing member is configured to prevent passage through the flexible sealing member of at least one of fluids and particulates into the internal volume from an external environment outside of the projectile stage when the interstage ring is coupled to the projectile stage; and wherein the flexible sealing member is exposed to and facing the external environment at least when the projectile stage is in a precoupled configuration with respect to a remainder of the projectile.

2. The projectile stage assembly according to claim 1, wherein said peripheral wall defines at least part of a peripheral wall of the projectile stage, wherein the peripheral wall has an internal wall surface facing and exposed to the internal volume, and an outer wall surface facing and exposed to the external environment.

3. The projectile stage assembly according to any one of claims 1 to 2, wherein the forward wall is an internal wall of the projectile stage.

4. The projectile stage assembly according to any one of claims 1 to 3, wherein the forward wall and the peripheral wall are configured to prevent passage through the forward wall and the peripheral wall, respectively, of at least one of fluids and particulates into the internal volume from the external environment outside of the projectile stage.03043355\8-ll5. The projectile stage assembly according to any one of claims 1 to 4, wherein said sealing member has a first surface exposed to and facing the internal volume in the precoupled configuration, and a second surface exposed to and facing the external environment when the stage is in the precoupled configuration, and wherein the internal surface and the external surface are separated by a sealing membrane thickness.

6. The projectile stage assembly according to any one of claims 1 to 5, wherein the sealing member is configured for deforming when subjected to at least a longitudinal force acting thereon.

7. The projectile stage assembly according to claim 6, wherein said force is generated by a non-zero pressure difference in the internal volume in the precoupled configuration.

8. The projectile stage assembly according to any one of claims 6 to 7, wherein said force is generated by a positive pressure difference in the internal volume acting on said first surface.

9. The projectile stage assembly according to any one of claims 6 to 8, wherein said force causes an aft longitudinal displacement of at least a central portion of the sealing member, and wherein optionally said aft longitudinal displacement is about 20% with respect to a radius of the sealing member.

10. The projectile stage assembly according to any one of claims 6 to 9, wherein said force causes the aft longitudinal displacement of at least a central portion of the sealing member to an aft longitudinal position aft of an aft peripheral edge of the projectile stage.

11. The projectile stage assembly according to any one of claims 6 to 8, wherein said force causes forward longitudinal displacement of at least a central portion of the sealing member.

12. The projectile stage assembly according to claim 11, wherein said forward longitudinal displacement is about 20% with respect to a radius of the sealing member.03043355\8-ll13. The projectile stage assembly according to any one of claims 11 to 12, wherein said force causes the forward longitudinal displacement of at least a central portion of the sealing member to a forward longitudinal position forward of an aft peripheral edge of the projectile stage, wherein optionally said forward longitudinal position is correlated to a forward projection of an adjacent portion of the remainder of the projectile, wherein further optionally said force is correlated to a reaction force generated responsive to abutment of the forward projection onto the sealing member, wherein further optionally said force is generated responsive to abutment of the second surface of the sealing member on the projection of the adjacent portion of the remainder of the projectile.

14. The projectile stage assembly according to any one of claims 5 to 13, wherein the sealing member comprises a base ring radially connected to a disc center plate via an intermediate ring.

15. The projectile stage assembly according to claim 14, wherein said base ring is configured for being sealably affixed to the inside wall of the interstage ring.

16. The projectile stage assembly according to any one of claims 14 to 15, wherein said base ring, said intermediate ring and said disc center plate are contiguous with one another and form a barrier that is configured for preventing flow therethrough, at least in a direction into the internal volume from the external environment, of at least one of the fluids and particulates, in the precoupled configuration.

17. The projectile stage assembly according to claim 16, wherein the fluids include any one or more of gases and liquids, and wherein the particulates include particulate matter, including one or more of debris, atmospherically carried solid contaminates including debris.

18. The projectile stage assembly according to any one of claims 5 to 17, wherein said thickness is uniform throughout the sealing member.

19. The projectile stage assembly according to any one of claims 14 to 17, wherein said thickness is non uniform, said thickness being greatest at the base ring and tapering to a minimum said thickness at the disc center plate.03043355\8-ll20. The projectile stage assembly according to any one of claims 14 to 19, wherein the second surface is coextensive with at least part of the base ring, all of the intermediate ring and all of the disc center plate on one longitudinal side of the sealing membrane, and wherein the first surface is coextensive with at least part of the base ring, all of the intermediate ring and all of the disc center plate on the other longitudinal side of the sealing membrane.

21. The projectile stage assembly according to any one of claims 14 to 20, wherein the disc center plate extends radially from a center of the sealing member by a first radius, wherein the intermediate ring extends radially away from the center from the first radius to a second radius, and wherein the base ring extends radially away from the center from the second radius to a third radius.

22. The projectile stage assembly according to claim 21, wherein said third radius corresponds to an internal radius of the inside wall of the interstage ring.

23. The projectile stage assembly according to any one of claims 21 to 22, wherein the first radius is about 20% of the second radius, and wherein the second radius is about 90% of the third radius.

24. The projectile stage assembly according to any one of claims 21 to 22, wherein the first radius is zero, and / or, the second radius is in the range between about 50% and about 90% of the third radius.

25. The projectile stage assembly according to any one of claims 14 to 24, wherein said base ring, said intermediate ring, and said disc center plate have different flexibilities with respect to one another, and wherein optionally said base ring and the disc center plate are relatively inflexible, and wherein said intermediate ring provides at least a majority of the flexibility for the sealing ring.

26. The projectile stage assembly according to any one of claims 6 to 25, wherein each one of a first area of said external surface and a second area of said internal surface are nominally constant, irrespective of whether or not said force is acting on the sealing membrane.03043355\8-ll27. The projectile stage assembly according to any one of claims 1 to 26, wherein said sealing member is made from a material that provides plastic or elastic deformation when subjected to said force.

28. The projectile stage assembly according to any one of claims 1 to 27, wherein the sealing member is made from flexible material, optionally including glass fiber panels embedded in a silicone matrix.

29. The projectile stage assembly according to any one of claims 1 to 28, wherein when the stage is coupled with respect to the remainder of the proj ectile the sealing member adopts a generally concave configuration, and, wherein when the stage is decoupled with respect to the remainder of the projectile the sealing member adopts a generally convex configuration.

30. The projectile stage assembly according to any one of claims 1 to 29, wherein said coupling system comprises a first coupling arrangement configured for selectively coupling the interstage ring with respect to the remainder of the projectile, and a second coupling arrangement configured for selectively coupling the interstage ring with respect to projectile stage.

31. The projectile stage assembly according to claim 30, wherein the first coupling arrangement is configured for permanently coupling the interstage ring with respect to the remainder of the projectile once the projectile stage is coupled to the remainder of the projectile in a coupled configuration, and wherein the second coupling arrangement is configured for reversibly coupling the interstage ring with respect to the projectile stage.

32. The projectile stage assembly according to claim 31, wherein the second coupling arrangement is configured for selectively coupling the interstage ring with respect to the projectile stage in the precoupled configuration and in the coupled configuration, and wherein the second coupling arrangement is further configured for selectively decoupling the interstage ring with respect to the projectile stage in a decoupled configuration, following the coupled configuration.

33. The projectile stage assembly according to claim 30, wherein the second coupling arrangement is configured for permanently coupling the interstage ring with respect to projectile stage, and wherein the first coupling arrangement is configured for reversibly03043355\8-llcoupling the interstage ring with respect to the remainder of the projectile once the projectile stage is coupled to the remainder of the projectile in a coupled configuration.

34. The projectile stage assembly according to claim 33, wherein the first coupling arrangement is configured for selectively coupling the interstage ring with respect to the remainder of the projectile in the coupled configuration, and wherein the first coupling arrangement is further configured for selectively decoupling the interstage ring with respect to the remainder of the projectile in a decoupled configuration, following the coupled configuration.

35. The projectile stage assembly according to any one of claims 1 to 29, wherein the projectile stage is integrally formed with the interstage ring, and wherein said coupling system comprises a first coupling arrangement configured for selectively and reversibly coupling the interstage ring with respect to the remainder of the projectile.

36. A projectile comprising the projectile stage assembly as defined in any one of claims 1 to 35, and further comprising an adjacent additional stage of the projectile detachably coupled with respect to the projectile stage assembly via said coupling arrangement.

37. A projectile comprising a first stage, a second stage, and an interstage ring, wherein: the interstage ring comprising a flexible sealing member configured to prevent passage through the flexible sealing member of at least one of fluids and particulates; the interstage ring comprises a coupling system configured for selectively coupling the interstage ring and the second stage with respect to one another, and for independently and selectively coupling the interstage ring and the first stage with respect to one another; the second stage comprises an internal volume, sealed at the aft end by the flexible sealing member, when the second stage is coupled with respect to the interstage ring via the coupling system; wherein the interstage ring and second stage are coupled with respect to one another via the coupling system to provide a stage assembly in a precoupled configuration.03043355\8-ll38. The projectile according to claim 37, wherein said coupling system comprises a first coupling arrangement configured for selectively coupling the interstage ring with respect to the first stage, and a second coupling arrangement configured for selectively coupling the interstage ring with respect to second stage.

39. The projectile according to claim 38, wherein the first coupling arrangement is configured for permanently coupling the interstage ring with respect to the first stage once the second stage is coupled to the first stage in a coupled configuration, and wherein the second coupling arrangement is configured for reversibly coupling the interstage ring with respect to the second stage.

40. The projectile according to claim 39, wherein the second coupling arrangement is configured for selectively coupling the interstage ring with respect to the second stage in the precoupled configuration and in the coupled configuration, and wherein the second coupling arrangement is further configured for selectively decoupling the interstage ring with respect to the second stage in a decoupled configuration, following the coupled configuration.

41. The projectile according to claim 38, wherein the second coupling arrangement is configured for permanently coupling the interstage ring with respect to second stage, and wherein the first coupling arrangement is configured for reversibly coupling the interstage ring with respect to the first stage once the projectile stage is coupled to the first stage in a coupled configuration.

42. The projectile according to claim 41, wherein the first coupling arrangement is configured for selectively coupling the interstage ring with respect to the first stage in the coupled configuration, and wherein the first coupling arrangement is further configured for selectively decoupling the interstage ring with respect to the first stage in a decoupled configuration, following the coupled configuration.

43. The projectile according to claim 37, wherein the second stage is integrally formed with the interstage ring, and wherein said coupling system comprises a first coupling arrangement configured for selectively and reversibly coupling the interstage ring with respect to the first stage.03043355\8-ll44. The projectile according to according to any one of claims 37 to 43, wherein the first stage comprises a forward projecting structure configured for projecting into an aft end of the second stage in the coupled configuration, and wherein: the flexible sealing member being exposed to and facing the external environment at least in the precoupled configuration; and the flexible sealing member being in abutting contact with the projecting member in the coupled configuration.

45. The projectile according to claim 44, wherein the forward projecting structure longitudinally projects forward of a forward peripheral edge by a spacing.

46. The projectile according to claim 45, wherein said spacing, as a percentage of an outer diameter of said forward peripheral edge, is in a range between 20% and 80%, or in a range between 30% and 70%, or in a range between 40% and 60%, or in a range between 30% and 50%.

47. The projectile according to any one of claims 44 to 46, wherein the forward projecting structure is any one of hemispherical and frusto-conical.

48. The projectile according to any one of claims 44 to 47, wherein the sealing member is longitudinally positioned with respect to the aft end of the second stage such that in the coupled configuration the forward projecting structure presses the sealing member in a forward direction to adopt a concave configuration.

49. The projectile according to any one of claims 44 to 48, wherein in the decoupled configuration, the sealing member is in any one of a convex configuration and a neutral configuration.

50. The projectile according to any one of claims 44 to 49, including one of the following:- wherein the projectile is a two-stage projectile;- wherein the projectile is a multi-stage projectile having more than two stages, wherein the second stage and the first stage correspond to an uppermost stage and to a penultimate stage, respectively, of the projectile;03043355\8-ll- wherein the projectile is a multi-stage projectile having more than two stages, wherein the second stage and the first stage correspond to two serially adjacent stages, respectively, of the projectile;- wherein the second stage and the first stage correspond to the payload and to an uppermost stage, respectively, of the projectile.03043355\8-ll

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