DE102017203303B4 - Disposable sub-hull structure for hypersonic spacecraft - Google Patents

Abstract

Throwable under hull structure (10) for a hypersonic space transport vehicle (12) following a buoyancy-assisted ascent trajectory,
wherein the lower fuselage structure (10) can be attached to the space transport vehicle (12) for covering a payload (20) carried under a fuselage (26) and / or wings (28) of the space transport vehicle (12) and
wherein the fuselage structure (10) is shaped in such a way that compression surges (14, 18), which occur in supersonic or hypersonic flight due to the fuselage structure (10) attached under the fuselage (26) and / or wing (28), increase the pressure under the wing (28) and thereby generate compression lift.

Description

TECHNICAL AREA

The present invention relates to a dropable hull structure for a hypersonic space transport vehicle following a buoyancy-assisted ascent trajectory. Furthermore, the invention relates to a space transport vehicle with a fuselage and a wing which is designed to follow a buoyancy-assisted ascent trajectory with hypersonic speed and which has a detachable sub-fuselage structure.

STATE OF THE ART

In order to enable the wide use and development of space, it is imperative that the transport of payloads into earth orbit is made possible at a significantly lower cost than before. Efforts have already been made to do this, in particular to improve conventional launchers. In this way, however, only limited cost reductions are possible, but fundamental breakthroughs in space transportation are not expected.

A regularly proposed alternative approach is fully reusable single-stage-to-orbit or two-stage-to-orbit hypersonic transport systems, which are also known as "space planes". Such space transport vehicles should in principle be suitable for enabling drastic cost reductions and were therefore examined intensively, particularly in the 1980s and 1990s. So far, however, none of these concepts has achieved a real breakthrough because either the engines did not meet expectations or the respective empty mass of the space transport system was too high.

The distance to a system that was considered to be technically feasible and economically sensible was not very great. It is therefore assumed that relatively small improvements in the prior art could be sufficient to be able to implement spaceplanes.

In military aviation in particular, it is known to use compression lift in buoyancy-assisted supersonic or hypersonic flight. Through a special contouring of the aircraft geometry in the area under the wing of the aircraft, the pressure increase generated by compression surges can be used specifically to additionally increase the lift of an aircraft. This principle was implemented in the USA in the form of the XB-70 bomber in the 1960s, for example, whereby the fuselage in which the engines were housed was shaped in such a way that the compression shocks it generated during supersonic flight significantly increased the pressure on the underside of the wing . This led to a significantly higher lift with constant resistance with a corresponding increase in the glide ratio and thus the range of the aircraft.

Geometric configurations that can generate compression lift by generating a pressure increase under the wing of an aircraft are known in principle. An example of this is in US 3 137 460 A from 1964.

However, the geometries of the fuselage structure of known aircraft such as the XB-70 bomber are not suitable for use in space transport vehicles, in particular because they cannot be protected from the aerothermodynamic loads when they re-enter the earth's atmosphere.

PRESENTATION OF THE INVENTION

Against the background of the prior art, the object of the present invention is first of all to provide a space transport system which enables a more efficient transport of payloads into the earth's orbit and, above all, the cost advantages of an ascent trajectory supported by buoyancy because it is reusable and possibly reusable Single-stage hypersonic spacecraft uses. In particular, the object of the present invention is also to provide a hypersonic space transport vehicle which is suitable as a reusable and ideally single-stage-to-orbit hypersonic space transport system and can thus lead to a drastic reduction in the cost of transporting payloads into earth orbit.

The object of the present invention is achieved by a detachable sub-hull structure according to claim 1 or also by a space transport vehicle according to claim 6. Advantageous features and further developments of the invention result from the respective subclaims.

A drop-off hull structure according to the invention for a hypersonic space transport vehicle following a buoyancy-assisted ascent trajectory can be attached to the space transport vehicle to cover a payload carried under a fuselage and / or under a wing of the space transport vehicle. The sub-fuselage structure is shaped in such a way that compression surges that occur in supersonic or hypersonic flight due to the sub-fuselage structure attached under the fuselage and / or the wing increase the pressure under the wing and thereby generate compression lift.

A first aspect of the invention is to reduce the hull of the space transport vehicle and to attach the payload to the fuselage instead of in a cargo hold. As a result, the fuselage of the space transport vehicle can be made significantly smaller and lighter than in previously known space transport vehicles with a cargo hold.

In the present context, payload means in particular the load to be transported into earth orbit (“payload”). In addition, the term “payload” in the present context can also include at least part of the fuel required to drive the spacecraft and a fuel tank used for this purpose.

In addition to the aspect of attaching the payload to the outside of the spacecraft to make the fuselage smaller and lighter, the sub-hull structure uses the knowledge that a clever geometric design of the sub-hull structure creates additional compression lift and thus reduces the aerodynamic drag of the spacecraft due to a reduction in the angle of attack can be. As a result, the fuel requirement required for atmospheric acceleration can be noticeably reduced, which in turn increases the performance of the space transport vehicle.

Another advantage of the sub-hull structure according to the invention is that the geometry of the sub-hull structure can be varied within certain limits and can thus be adapted to different sizes and geometries of the payload and, if appropriate, to variable amounts of additional fuel. In contrast to a space transport vehicle with a cargo space inside the fuselage, which was designed for a certain payload or as versatile as possible, for example by standard dimensions, a space transport vehicle according to the present invention can transport a large number of different payloads in an optimized manner into the earth's orbit , because the sub-hull structure can be geometrically optimized for each payload, thereby minimizing the mass and resistance of the spacecraft.

Another advantage of the invention is that by attaching the payload to the spacecraft, the possibility of easier integration of the payload on the spacecraft is created. For example, the payload can be easily pushed underneath the space transport vehicle on the ground and attached to it. Previous spaceplane concepts usually provide a payload bay inside the vehicle that is accessible via hinged doors on the fuselage back; a crane required for this is not required in the proposed invention.

With regard to the design of the sub-fuselage structure, so that compression surges, which occur in supersonic or hypersonic flight through the sub-fuselage structure, generate an increase in pressure under the wing and thereby compression lift, it should be noted that the location of the compression surges depends in particular on the airspeed. The flight speed of a space transport vehicle varies over a very large speed range on its way from earth to the edge of the atmosphere, unlike an airplane that always flies within the atmosphere. The geometry of the sub-hull structure can be optimized for relatively low speeds in the low supersonic range or for high speeds in the hypersonic range. For the present invention, a mean value between low and high supersonic velocities (or low-medium hypersonic velocities) of the geometry of the sub-trunk structure is preferably used. This is possible through fundamentally known simulations of the compression surges and is basically in the area of expert knowledge. For example, the system can be optimized for Mach numbers from 1-6 ... 10, i.e. from supersonic to the low-medium hypersonic range, whereby the actual design of the system can depend heavily on the overall system design.

Another advantage of the sub-fuselage structure according to the invention is that the sub-fuselage structure can be thrown off after leaving the denser atmospheric layers, whereby the payload is released and the mass loss achieved by dropping the sub-fuselage structure further reduces the mass to be accelerated into orbit and thus additionally the performance of the spacecraft improved.

If the dropped hull structure cannot be reused, it can be made from relatively simple and inexpensive materials and with low safety factors, since in most cases the hull structure only has to maintain a predetermined contour, but does not bear any vehicle loads. Damage such as creeping, oxidation or limited plastic deformation can therefore be tolerated. This further leads to improved cost efficiency of transporting the payload.

According to a preferred embodiment, the sub-hull structure has a fuel tank. This can be, in particular, an additional tank to a main tank of the space transport vehicle, the contents of which have been used up within the denser atmospheric layers and which can thus be thrown off after leaving these denser atmospheric layers. Such a fuel tank increases the complexity and thus also the costs of the sub-hull structure, but at the same time enables a further reduction in the mass to be accelerated into the earth's orbit.

According to a further preferred embodiment, the sub-fuselage structure further comprises a flap, preferably a plurality of flaps, which can be extended in such a way that the compression shocks under the wing can be influenced by the flap or the flaps. In particular, a displacement of a position of a pressure point of the compression lift can be realized by actuating the flap or flaps, i.e. the pressure point of the compression lift can be shifted through the flap or the flaps. The flap or flaps are preferably arranged laterally on the sub-hull structure.

By means of the preferred flap or flaps of the under fuselage structure, the effect of the compression buoyancy can be maintained over a larger speed range and / or its intensity can be changed, which is advantageous for a space transport vehicle that does not take up a certain cruise speed, but faster and faster during its flight through the earth's atmosphere becomes. In addition, the pressure point position can be adjusted not only with regard to the speed range to be flown through, but also to a possible change in the center of gravity.

According to a further preferred embodiment, the under fuselage structure further comprises a wheel undercarriage which is suitable for supporting the space transport vehicle during its launch. In this embodiment, the under fuselage structure not only performs a cladding function, but also carries loads of the under fuselage structure and / or other parts of the space transport vehicle during the start run. In this case, the sub-trunk structure can be made somewhat more stable and solid, which can lead to a higher mass of the sub-trunk structure. On the other hand, at least a part of the mass of a separate take-off landing gear can thus be saved, the additional mass of the under fuselage structure being thrown off during the flight and the mass to be accelerated into orbit thus being further reduced compared to the take-off mass.

In an advantageous embodiment, the sub-fuselage structure further comprises a parachute for a gentle landing of the dropped sub-fuselage structure on the earth, such a parachute is particularly important in embodiments in which the sub-fuselage structure makes a significant cost contribution to the flight into the earth's orbit or in which the sub-fuselage structure contributes their impact on earth could pose a danger to living beings or objects. In particular, in the case of a light hull structure that serves only as a covering, it is also possible to dispense with such a parachute, especially if the trajectory of the spacecraft is planned so that the hull structure is at sea or in an uninhabited area such as a desert will hit earth.

A space transport vehicle according to the invention with a fuselage and a wing, which is designed to follow a buoyancy-assisted ascent trajectory with supersonic or hypersonic speed, comprises a detachable sub-fuselage structure, which is detachably attached under the space transport vehicle to cover a payload carried under the fuselage and / or under the wing is. The sub-fuselage structure is shaped and arranged on the space transport vehicle so that the compression shocks that occur in the supersonic flight and hypersonic flight through the sub-fuselage structure generate an increase in pressure under the wing and thus compression lift.

The sub-hull structure is advantageously a sub-hull structure as described above.

Such a space transport vehicle makes it possible to transport payloads into earth orbit much more efficiently than is possible with conventional carrier systems, and can thus represent a realization of the concept of a fully reusable single-stage-to-orbit space transport vehicle.

The space transport vehicle preferably has a flat underside after the lower hull structure has been thrown off. Such a flat underside is particularly advantageous with regard to the re-entry into the earth's atmosphere, in which very high thermal loads on the space transport vehicle arise from the friction of the air on the space transport vehicle. A flat underside, for example, means that a heat shield or similar devices for protecting the space transportation vehicle can be effectively attached and used. Furthermore, a flat underside prevents the occurrence of secondary compression impacts on flow obstacles that lead to local Excessive temperatures and corresponding additional loads on the heat shield would result.

According to a further preferred embodiment, the space transport vehicle further comprises a heat protection panel which can be extended from the fuselage and / or wing, in particular in order to protect the payload from an aerothermomechanical load after the lower fuselage structure has been thrown off, and can be retracted to the fuselage and / or the wing. in particular in order to absorb an aerothermodynamic load on the space transport vehicle when the space transport vehicle re-enters the earth's atmosphere.

The space transport vehicle preferably comprises a plurality of heat protection panels, which are preferably arranged frontally and laterally with respect to the payload and can be extended accordingly. Extendable heat protection panels arranged only frontally or only laterally with respect to the payload are also conceivable within the scope of the present invention. The heat protection panel serves or the heat protection panels serve in particular to protect the payload after the sub-hull structure has been thrown off and are used for this purpose rather in atmospheric layers with very thin air. In these atmospheric layers, the space transport vehicle hardly flies due to aerodynamic lift, so that the lack of support from the compression lift due to the dropping of the lower hull structure and the possibly increasing drag coefficient of the space transport vehicle are also negligible. However, the lower mass of the spacecraft after the drop in the hull structure improves the efficiency of the further acceleration according to the rocket principle, and the heat protection panels that are required anyway for re-entry can protect the payload, for example, against pressure surges and against aerothermodynamic loads when extended.

The present invention allows existing concepts in space transport vehicles to be further developed in such a way that the possible payload is increased and the costs for transporting the payload into the earth's orbit can be considerably reduced.

Further features of the invention result from the following description of the figures and the entirety of the claims.

Figure list

• 1a and 1b show a view of a spacecraft from below a fuselage and a wing with a preferred fuselage structure.
• 2nd shows a view of a spacecraft from below the fuselage and the wing with another preferred sub-fuselage structure.
• 3a to 3c each show a schematic side view of a space transport vehicle with a detachable hull structure.
• 3d shows a schematic side view of a space transport vehicle with attached payload after dropping the under hull structure.
• 4a and 4b show a front view of a space transport vehicle with the hull structure attached below.
• 5a and 5b show a schematic side view of a space transport vehicle with frontally arranged in front of the payload heat protection panel to protect the payload.
• 6a and 6b show a schematic front view of a space transport vehicle with heat protection panels arranged laterally to the payload to protect the payload.
• 7 shows a schematic side view of a space transport vehicle with a further preferred sub-hull structure.

WAYS OF CARRYING OUT THE INVENTION

1a and 1b show a schematic view from below of a space transport vehicle 12th according to a preferred embodiment. The space transport vehicle 12th has a detachable hull structure 10th on that under the fuselage or the wing of the spacecraft 12th is appropriate. The hull structure 10th is shaped so that shock waves 14 that are in supersonic flight and hypersonic flight on the under fuselage structure 10th arise, an increase in pressure under the wing and thereby generate compression lift. This increases the glide ratio of the space transport vehicle in flight states in which the space transport vehicle follows a buoyancy-assisted ascent trajectory in a basically known manner. Thus, the resistance of the space transport vehicle can be reduced by the compression buoyancy, which means that the energy required for acceleration into the earth's orbit is lower than previous space transport vehicles.

Different forms of sub-fuselage structures are fundamentally suitable for generating such a pressure increase under the wing and thus compression lift. 1a and 1b schematically show two different examples, wherein in 1a a rounded tip and in 1b a sharp tip indicated are. The hull structures can also have different opening angles and be formed at least partially concave, at least partially convex and / or at least partially flat on their surface.

2nd shows a further preferred embodiment of a space transport vehicle 12th with hull structure 10th . In contrast to that in the 1a and 1b The embodiment shown has the sub-hull structure 10th out 2nd two flaps 16 on their sides, which extend and retract the shape and arrangement as well as the strength of the compression shocks 14 , 18th in supersonic or hypersonic flight.

In particular, by extending the flaps 16 a secondary shock 18th generated, which causes an additional, secondary compression lift in a certain speed range, which primarily serves to control the pressure point position and thus the aerodynamic trim of the spacecraft. If this secondary compression buoyancy cannot or should not be generated, for example because the spacecraft is moving 12th The flaps can be in an unsuitable speed range or the additional compression lift would lead to an undesirable shift of the pressure point position 16 to reduce air resistance. In addition, the flaps 16 also be extended only in the course of the flight in order to increase the air resistance of the space transport vehicle in an initial phase of the flight 12th to minimize.

The 3a to 3c show a schematic side view of a space transport vehicle 12th with a detachable hull structure 10th . There are various geometrical configurations of the sub-hull structure 10th shown, which are intended to illustrate that there are various ways to achieve a pressure increase under the wing and thus compression lift by the compression shocks occurring in supersonic and hypersonic flight.

3d shows a schematic side view of the space transport vehicle 12th with the payload no longer covered by a hull structure 20 . The payload 20 recognizably occupies a smaller space than the detachable sub-hull structure, but is not particularly designed with regard to the targeted influencing of the compression shocks and thus the generation of the compression lift and also with regard to its air resistance.

4a and 4b show a schematic front view of a space transport vehicle 12th with a hull 26 and a wing 28 as well as the one under the wing 28 attached sub-hull structure 10th . These figures in turn show different possible configurations of the geometry of the sub-hull structure 10th .

5a and 5b show a selective, schematic side view of a further preferred embodiment of a space transport vehicle 12th . The in the 5a and 5b The configuration shown may change after the sub-hull structure has been dropped 10th to adjust. The payload 20 is essentially exposed, but is still covered by a heat protection panel after the lower hull structure has been thrown off 22 especially protected from an aerothermomechanical load.

In 5a is the heat protection panel 22 head-on in front of the payload 20 arranged. After the payload 20 away from the spacecraft 12th has solved, the heat protection panel 22 back to the surface of the underside of the spacecraft 12th be retracted to for the reentry of the spacecraft 12th an aerothermodynamic load on the spacecraft in the earth's atmosphere 12th to record. The heat protection panel 22 can already under the hull structure 10th have been extended or only after the lower hull structure has been dropped 10th be extended.

6a and 6b show the configurations similar to the 5a and 5b in a schematic front view. 6b shows how heat protection panels 22 on the wing 28 are retractable. The front heat protection panel 22 , this in 5a and 5b is shown in 6a and 6b been left out. The are similar in 6a and 6b shown side heat protection panels 22 in the 5a and 5b Not shown.

According to a preferred embodiment, heat protection panels are 22 both before and next to the payload 20 arranged to protect them from aerothermomechanical loads and other external influences. The space transport vehicle 12th can also be used with just one or more head-on payloads 20 arranged heat protection panel or heat protection panels or with only one or more to the side of the payload 20 arranged heat protection panel or heat protection panels.

7 shows a further preferred embodiment of a space transport vehicle 12th with a sub-hull structure 10th , with the in 7 shown hull structure 10th a wheel undercarriage 24th includes that in support of the spacecraft 12th is suitable during its starting run. The wheel chassis 24th can preferably be separated from the hull structure and the spacecraft after the take-off run 12th be solved or after leaving the earth's atmosphere together the sub-hull structure 10th from the spacecraft 12th be dropped. In this second case in particular, it is advantageous if the sub-hull structure 10th also a parachute for a gentle landing of the dropped hull structure 10th exhibits on earth because, above all, the wheel chassis 24th may have an inherited mass that can cause collateral damage when impacting the earth. Furthermore, the allegedly undamaged under fuselage structure can be recovered and reused during a parachute landing.

The examples described above serve only to illustrate the invention in some preferred embodiments and are not to be understood as restrictive. In addition, it is possible to combine individual features of individual embodiments with other features of other embodiments.

Claims (9)

Throwable under hull structure (10) for a hypersonic space transport vehicle (12) following a buoyancy-assisted ascent trajectory, wherein the lower fuselage structure (10) can be attached to the space transport vehicle (12) for covering a payload (20) carried under a fuselage (26) and / or wings (28) of the space transport vehicle (12) and wherein the fuselage structure (10) is shaped in such a way that compression surges (14, 18), which occur in supersonic or hypersonic flight due to the fuselage structure (10) attached under the fuselage (26) and / or wing (28), increase the pressure under the wing (28) and thereby generate compression lift. Disposable sub-hull structure (10) Claim 1 , characterized in that the further comprises a fuel tank. Disposable sub-hull structure (10) Claim 1 or 2nd , characterized in that it further comprises a flap (16) which can be extended in such a way that the compression impacts (14, 18) under the wing (28) can be influenced by the flap (16), in particular a displacement of a position of a pressure point of the compression buoyancy can be achieved by the flap (16), the flap (16) preferably being arranged laterally on the lower hull structure (10). Disposable lower hull structure (10) according to one of the preceding claims, characterized in that it further comprises a wheel undercarriage (24) which is suitable for supporting the space transport vehicle (12) during a launch run. A dropable hull structure (10) according to any one of the preceding claims, characterized in that it further comprises a parachute for a smooth landing of the dropped hull structure (10) on the earth. Space transport vehicle (12) with a fuselage (26) and a wing (28), which is designed to follow a lift-assisted ascent trajectory with supersonic or hypersonic speed, comprising a detachable lower fuselage structure (10) which is detachably attached under the space transport vehicle (12) to cover a payload (20) carried under the fuselage (26) and / or wings (28), wherein the sub-fuselage structure (10) is shaped and arranged on the space transport vehicle (12) in such a way that compression shocks (14, 18), which arise from the sub-fuselage structure in supersonic or hypersonic flight, generate an increase in pressure under the wing (28) and thereby compression lift. Space transport vehicle (12) after Claim 6 , characterized in that the dropable hull structure (10) according to one of the Claims 2 to 5 is trained. Space transport vehicle (12) according to one of the Claims 6 and 7 , characterized in that the space transport vehicle (12) has a flat underside after the lower hull structure (10) has been thrown off. Space transport vehicle (12) according to one of the Claims 6 to 8th , characterized in that it further comprises a heat protection panel (22) which can be extended from the fuselage (26) and / or wing (28) in order to protect the payload (20) from an aerothermomechanical load after the lower hull structure (10) has been thrown off , and on the fuselage (26) and / or wing (28) can be retracted, in particular in order to absorb an aerothermodynamic load on the space transport vehicle (12) when the space transport vehicle (12) re-enters the earth's atmosphere.

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