DE4422617C1 - Landing-shock-damping system for spacecraft - Google Patents

Abstract

The system uses a cushion (13) which can be formed by combining two ingredients of reactive resin. The chemical reaction to form the cushion can be started on or shortly after re-entry, using the high temperatures then generated. The cushion can be formed by filling a sack (10), toroidal in shape when filled, with foam material. Alternatively, the heat-shield can be extended downwards from the cabin after re-entry by pneumatic rams, the intervening space being then filled with foam material.

Description

The invention relates to a method for damping the landing impact Spacecraft, in particular a manned or unmanned capsule, according to the preamble of claim 1.

For a safe, gentle landing, usually on parachutes Basically sinking spacecraft are four different possibilities known:

• - Steamed landing legs
• - Retrorockets
• - crash structures
• - airbags.

Combinations are also possible and some have already been implemented. For example, retrorockets with landing legs or retrorockets with Crash structures.

Land engines are to be understood under the term "retrorockets" briefly produce a thrust that counteracts gravity and thereby the spacecraft in question immediately in front of the floor slow down the movement.

Both landing legs and retrorockets with associated fuel system are technically complex and require a considerable amount of space and noticeably increase the mass of the spacecraft.

Crash structures are deformable structures, which usually lie between the Heat shield and the cabin / payload are arranged. These take the kinetic energy of the spacecraft when landing through plastic ver formation on. Because of the small available installation volume  The realizable thickness is between the heat shield and the cabin or payload of these crash structures relatively small, so that the damping stroke for a gentle braking on landing is usually not sufficient. Therefore have to usually additional measures for landing shock absorption, such as. B. Retrorockets.

DE-AS 11 87 497 describes a device for damping the landing gear known from loads dropped on parachutes, which according to Re trorocket principle allows gas to flow out of nozzles. However, it does is not about combustion exhaust gas, but about "cold", stored Compressed gas. The latter is made up of several nozzles between a platform and blown out of the ground, so that a damping gas cushion for a short time should arise. It is doubted whether the desired gas cushion effect actually occurs.

The use of gas cushions with textile or polymeric covers, d. H. of airbags, for landing shock absorption is for example from the DE-OS 41 18 300 and the US-PS 2 887 055 known. Airbag systems are relative light, simple and require little space when inactive. Everything However, it is rather difficult to adapt them to varying landing conditions (sink speed, side drift etc.). At high landing speeds There is a risk of at least individual chambers bursting or the risk of rebounding due to elastic energy storage tion with insufficient damping. Airbag systems are generally few suitable for absorbing lateral forces, d. H. of shear loads. The Consequences may be that a spacecraft landing with side drift around tilts or overturns. Another serious disadvantage of Airbag systems is that in relation to crash structures the Ener absorption capacity as a result of blowing off at the same stroke by approx. 50% is less.

Compared to these known solutions with their disadvantages The object of the invention is to provide a method for damping the landing impact  of a spacecraft indicating the advantages of airbag systems such as low installation volume and weight, but has their aftermath avoids parts, that is, for the absorption of vertical and horizonta len impact components is suitable and with optimal damping to maxi is capable of absorbing energy without any risk of rebounding or Failure (bursting, destruction, etc.).

This object is achieved by the characterizing part of claim 1 Features mentioned solved in connection with the generic Characteristics in the generic term.

The invention thus proposes as a replacement for an airbag or for other crash structures a mechanically resilient before landing To generate foam pillows, which the kinetic energy when landing in the essentially absorbs through plastic deformation.

The components required for this (foam cartridges, trigger device tings etc.) are state of the art, that means tried and tested and easy available. By adapting / optimizing the parameters such as pillow shape, Pillow volume, foam density, hardness, degree of curing etc. achieve the desired service conditions. Because of very little out curing times (e.g. a few seconds with two-component reactive resin foam) the foam cushion can be generated shortly before landing. Of course, it is also possible to have several separate foam pillows with the same or different properties.

The sub-claims 2 to 5 contain preferred embodiments of the Ver driving according to claim 1.

The invention will be explained in more detail with reference to the drawing tert. A simplified representation shows:  

Fig. 1 shows a capsule with cabin and heat shield before generating a dämp fenden foam pad,

Fig. 2 shows the same capsule without heat shield with an enveloped, torusför-shaped foam cushion,

Fig. 3 shows a capsule with cabin and a downward extendable away from the cabin heat shield before producing a foam pad,

Fig. 4 the same capsule with the heat shield extended downwards and with a foam cushion between the cabin and the heat shield.

The capsule 1 according to Fig. 1 carries in its structure 3, a cab 5, in which a crew of one or more persons may be accommodated. When re-entering the earth's atmosphere, the capsule 1 is thermally protected by the heat shield 7 , which is shown in section Darge. Between the cabin 5 and the heat shield 7 are attached to the Kap sel structure 3 attached foam cartridges 11 can be seen , which contain two separate components of a reactive resin foam in the inactive state.

The parachutes or paragliders which brake the gravitational case of the capsule 1 are not shown for the sake of simplicity.

Fig. 2 shows the state of the capsule 1 just before landing with use bereitem foam pad 13. In order to create space for this, the heat shield 7 was previously thrown off (process not shown). So that the foam hardens in a defined form, it was introduced into a shell in the form of a toroidal sack 10 . Such a sheath, for example made of plastic fabric, is preferably gas-permeable but foam-impermeable. Depending on the shape of the cover, practically any foam pillow shape can be realized, whereby several, separate pillows can be combined.

If the exact pillow shape is not so important, you can do that Foam also free, without casing, swell and harden. When opening hit on the surface of the earth - or on a surface of water the foam cushion is deformed more or less plastically.

The aim should be to keep the elastic deformation component as small as possible hold to largely prevent rebound effects. In this sense a foam structure that is intentionally not full can be beneficial is constantly hardened.

The capsule 2 according to FIG. 3 also comprises a structure 4 , a cabin 6 , a heat shield 8 and foam cartridges 12 between the cabin 6 and the heat shield 8 . The peculiarity here is that the distance between Kabi ne 6 and heat shield 8 can be significantly increased by means of a pneumatic actuator 9 actuated handlebar arrangement. This state with a large distance is shown in Fig. 4. The foam cushion 14 completely fills the intermediate space and thus acts as a strongly damping crash structure between the heat shield 8 and the cabin 6 . The heat shield 8 which at least superficially occurs when it is reinserted here receives the undamped, hard landing shock.

Reference list

1 capsule
2nd
3 capsule structure
4th
5 cabin
6
7 heat shield
8th
9 pneumatic cylinders
10 sacks, toroidal
11 foam cartridge
12th
13 foam pillows
14.

Claims (5)

1.Procedure for damping the landing impact of a spacecraft, in particular a manned or unmanned capsule, which approaches the earth's atmosphere after re-entry ν due to the activation of at least one aerodynamic braking device, in particular parachutes, with the aid of an activatable one before landing , resiliently deformable damping structure, characterized in that at least one mechanically resilient foam cushion ( 13 , 14 ) is generated in the period between reentry and landing on the underside of the spacecraft body (capsule 1, 2 ) facing the earth's surface, which foam cushion ( 13 , 14 ), which the kinetic energy of Raumflugkör pers (capsule 1, 2 ) takes up on landing essentially by plastic deformation. 2. The method according to claim 1, characterized in that the foam cushion ( 13 , 14 ) is produced by combining two components of a reaction resin. 3. The method according to claim 1 or 2, characterized in that the chemical reaction to produce the foam pad during or briefly after the reentry phase of the spacecraft using the prevailing high temperatures is initiated. 4. The method according to one or more of claims 1 to 3, characterized in that the foam cushion ( 13 ) is produced by foaming a - in the filled state - toroidal bag ( 10 ). 5. The method according to one or more of claims 1 to 3, for damping the landing impact of a spacecraft with a self-supporting heat shield protecting its cabin in the re-entry phase, characterized in that after the reentry of the spacecraft (capsule 2 ) the heat shield ( 8 ) from the cabin ( 6 ) drive downwards (pneumatic cylinder 9 ), and the resulting intermediate space is foamed (foam cushion 14 ).