RU2165870C2 - Transportation space system - Google Patents

Abstract

FIELD: rocketry and space engineering; single-stage facilities for injection of payloads into Earth satellite orbit. SUBSTANCE: system includes payload bay and launch vehicle arranged in tandem. Launch vehicle is provided with liquid-propellant engine plant with central body and modular combustion chambers which are secured on the outside of bearer frame inside fairings which are mounted at spaced relation to central body. Gaseous hydrogen rings heated to high temperature are admitted to active leg into external atmosphere from combustion chambers (from screen of their internal cooling). Excessive hydrogen is burnt finally in incoming flow of air where fairing with chambers are introduced. EFFECT: increased specific impulse of lox/liquid hydrogen engines; increased mass of payload. 5 dwg, 1 tbl

Description

 The space transport system (TCS) refers to rocket and space technology and is intended for single-stage means of launching payloads (GH) into the orbit of an Earth satellite.

The prospect of space exploration and use largely depends on the effectiveness of the TCS, mainly determined by the cost of launching the orbit of the GHG and the reliability of the TCS. The first projects to reduce the cost of elimination by switching to reusable systems (Space Shuttle and Buran) were unsuccessful. This is due to an attempt to solve new problems by old methods. In an effort to maximize the mass return of the systems, they extremely accelerated their liquid rocket engines (LRE) by the pressure in the combustion chamber (more than 200 kg / cm ² ). As a result, Shuttle's oxygen-hydrogen engines are forced to sort out after each flight, instead of the projected life of 55 flights. Domestic hydrogen liquid propellant rocket engines provided only single use. However, the decisive role for the effectiveness of TCS is currently gaining reliability due to a significant increase in the cost of GHGs. For example, casualties in accidents of the Titan-4 launch vehicle (LV) in 1993 and 1998. estimated at $ 1 billion. [1]. The cost of the Hubble orbiting telescope, the most complex communications satellites, reaches $ 200,000 / kg [2]. Even with the profitability of launch vehicles of $ 1,000 per kg payload, more than 200 commercial launches will be required only to compensate for the loss of such a device. The existing launch vehicle generation has practically exhausted the possibilities of increasing reliability (duplication of elements, constructive solution of systems, maximum amount of ground mining, etc.). A significant increase in reliability can be obtained on single-stage TKS, where operations to separate the stages and start the engines on the withdrawal path are excluded. The main disadvantage of single-stage systems is the low relative mass of GHGs. This disadvantage is compounded by the direct dependence of the GHG mass on the mass of the TKS structure - an increase in the mass of the structure by the same amount reduces the GHG. The specified disadvantage can be eliminated by increasing the specific impulse of the engine. As the experience of the Shuttle and the Buran showed, the traditional way of increasing the specific impulse due to forcing the liquid propellant rocket engine by the pressure in the combustion chamber is unacceptable for reusable systems.

 The famous project is a single-stage reusable aircraft-type apparatus NASP, the creation of which was declared in the late 80s a national task of the United States [3,4]. The increase in specific impulse in this TKS is achieved by using air in a combined propulsion system (DU), including turbojet, ramjet engines and supersonic combustion engines. Several billion dollars were spent on the NASP program. The work carried out showed the impossibility of increasing the efficiency of such an apparatus with the current level of technology due to a significant increase in the mass of the combined remote control and the difficulty of implementing supersonic combustion. Currently, development work on this program has been discontinued. Its positive results include confirmation of the effectiveness of supersonic combustion of hydrogen [4, Fig. 1]. At the same time, the problem of mixture formation of hydrogen-air fuel due to the short duration of stay of the supersonic jet in the combustion zone has been identified as the main one for supersonic combustion propulsion, [4, p. 4].

 The main project currently being implemented in the USA is the single-stage vertical take-off and horizontal landing apparatus Venture Star, which is being created as part of the RLV program with access to flight tests in 1999 [5]. The success of the program is associated with the use of new oxygen-hydrogen rocket engines with a central body and carbon-fiber tanks of fuel components. A characteristic feature of an engine with a central body is the property of auto-regulation, i.e. natural provision of the optimum regime for the specific impulse, when the pressure at the nozzle exit is maintained equal to atmospheric on the main part of the withdrawal path. Carbon fiber tanks can significantly reduce the weight of the structure. The disadvantages of this device are associated with its horizontal landing, which imposes severe restrictions on the dimensions (to ensure acceptable aerodynamic characteristics). As a result, the central body is made with a small degree of expansion, which limited the specific void impulse to 455 kg · s / kg. Another consequence of overall limitations was the need to carry hydrogen tanks as carriers, which significantly reduces the mass advantages of carbon fiber material, because the specific tensile strength of the latter is 25% higher than the specific compressive strength [6].

 A known project of reusable oxygen-hydrogen TCS vertical take-off and landing type "Shuttlecock", free from these shortcomings and adopted as a prototype of the invention [7]. The TCS contains a tandemly located GHG compartment and a single-stage launch vehicle, including tanks of fuel components and a liquid propellant rocket engine with a central body and modular combustion chambers mounted on the outside of the power frame under the cowls. Vertical landing removes restrictions on the dimensions of the central body, which allows to increase the degree of expansion of the LRE and bring the specific impulse to about 470 kg · s / kg. The installation of GHGs on the lateral oxygen storage tanks unloads the central hydrogen tank from compressive forces, ensuring its operation only in tension. However, the large diameter of the launch vehicle leads to increased aerodynamic drag at the elimination site with a corresponding loss in the mass of the greenhouse.

 The objective of the invention is to increase the mass of GHGs. The task is achieved in that in a TCS containing a tandem compartment of the PG and LV, including tanks of fuel components and a liquid propellant rocket engine with a central body and modular combustion chambers mounted on the outside of the power frame under the cowls, the combustion chambers are located inside the cowls of closed shape installed with clearance relative to the power frame and the central body.

The invention is illustrated by drawings:
FIG. 1 - cargo version of the TKS;
FIG. 2 - manned version of the TCS;
FIG. 3 is a diagram of the functioning of the TCS;
FIG. 4 - installation diagram of modular combustion chambers;
FIG. 5 is a view along arrow A of FIG. 4.

The drawings show:
1 - booster;
2 - payload;
3 - suspended hydrogen tank;
4 - power frame;
5 - carrying tanks of oxygen;
6 - swivel joints;
7 - LRE;
8 - modular combustion chambers;
9 - the central body;
10 - steering cameras;
11 - fairings of combustion chambers;
12 - stabilizing parachute;
13 - fixing cables;
14 - power nodes mounting the combustion chambers.

 RN 1 provides the launch of GHG 2 into orbit. Suspended hydrogen tank 3 is used to accommodate liquid hydrogen. The power frame 4 structurally links the main elements of the TCS. Bearing oxygen tanks 5 are used to accommodate liquid oxygen and the fastening of the steam generator, after a turn around the hinges 6 - to stabilize and land the pH 1 upon return. The liquid propellant rocket engine 7 provides the thrust necessary for launching the TCS into orbit and landing of the launch vehicle 1. The main part of the thrust is created by modular combustion chambers 8. The central body 9 receives the thrust of the combustion products flowing from the chambers 8 and the additional thrust of the afterburning of the curtain of internal cooling of the chambers 8 in a supersonic flow . Steering chambers 10 create control efforts along the roll channel. The fairings of the combustion chambers 11 protect the chambers 8 from the incoming air and form a flow for afterburning the hydrogen curtain of the internal cooling of the chambers 8. The stabilizing parachute 12 turns the PH 1 to the landing position and reduces the landing speed. The locking cables 13 secure the tanks 5 in the landing position and provide cushioning during landing. The power unit mounting the combustion chambers 14 transmits the thrust of the combustion chambers 8 to the power frame 4.

 The TCS operates as follows. In the initial position, the TCS is vertically installed at the starting position. Tanks 3 and 5 are charged with liquid hydrogen and oxygen. The functioning of the system begins with the launch of the liquid-propellant rocket engine 7. At the same time, due to air ejection by the gas jets of the modular combustion chambers 8, the afterburning of the hydrogen curtain of internal cooling in a supersonic flow begins. The formation of the air flow for afterburning the hydrogen curtain is provided by the fairings of the combustion chambers 11. Upon reaching the required draft, the product is launched. As the speed pressure of the incoming air flow increases, the process of supersonic combustion intensifies. After going beyond the atmosphere, the TCS is put into orbit only on the LRE. In orbit, the GHG 2 is separated from the RN 1 and performs its functional purpose. The launch vehicle is in standby orbit for landing in the launch area. Before the descent, the tanks 5 are deployed around the swivel joints 6 and are fixed in the rear position by the fixing cables 13 (Fig. 3), forming a shuttle-type arrangement self-stabilizing during the passage of the atmosphere. Entering into the atmosphere is ensured by the issuance of a brake impulse of the liquid propellant rocket engine 7. After passing through the zone of high high-pressure heads, the stabilizing parachute 12 unfolds into the landing position. A soft landing is provided by the rocket engine 7, additional depreciation is due to the elasticity of the cables 13 and the rotation of the tanks in the swivel joints 6. After carrying out maintenance work, the LV is preparing for a new flight.

A positive effect of the invention is an increase in the mass of GHGs by increasing the specific impulse of the liquid propellant rocket engine by afterburning the cooling curtain of the combustion chambers in a supersonic flow. As already mentioned above, the main problem of supersonic combustion, which was never implemented in the American single-stage NASP apparatus, is the mixture formation of hydrogen-air fuel. The proposed design solves this problem by moving the liquid-fuel rocket engine modular chambers into the incoming air stream, while thin rings of hydrogen gas heated up to high temperature, already prepared for combustion, enter the air atmosphere from the combustion chambers. Modern oxygen-hydrogen rocket engines operate with a significant excess of hydrogen (the ratio of the components of the fuel is K _m = 6: 1 with a stoichiometric ratio of 8: 1) used for the curtain of internal cooling of the combustion chambers. As can be seen from the above ratio, the flow through the curtain reaches 3% of the total fuel consumption. For example, for the remote control systems of the Shuttle and Buran systems with a working supply of oxygen-hydrogen fuel of about 700 tons, the amount of hydrogen released into the atmosphere exceeds 20 tons.

To obtain a quantitative value of the increase in the mass of GHGs in comparison with the prototype, the average trajectory increment of the specific impulse in the supersonic combustion circuit ΔIav.t. The following initial data were adopted:
hydrogen consumption through the cooling curtain is 3% of the total fuel consumption;
the limiting value of the velocity of the incident flow is limited to 7M (going beyond the atmosphere for a ballistic trajectory of removal);
the average specific impulse of supersonic combustion of hydrogen is about 2000 kg · s / kg (graph of Fig. 1 [4], extrapolated to the low-velocity zone);
the amount of fuel produced by the rocket engine before reaching a speed of 7M is about 70% of the working fuel supply;
Losses due to incomplete combustion and imperfection of the supersonic combustion process are assumed to be 30% (an order of magnitude larger than the LRE).

Then
ΔIav.t. = 2000 · 0.03 · 0.7 = 30 kg · s / kg.

 Based on this value of the increment of the average trajectory pulse, the table shows the comparative data of the prototype and the proposed TCS.

 As the evaluation results show, the mass of GHG increases with the implementation of the invention by 2.3 times, which significantly reduces the risk of developing single-stage TCS with the current level of technology.

The optimal design from the point of view of implementing the invention at the current level of technology seems TCS type "Shuttlecock". Compared with the considered analogues - single-stage devices NASP and Venture Star - it has the following advantages:
1. Vertical launch and landing remove severe restrictions on the midship of the apparatus, which allows you to perform a rocket engine with a high degree of expansion and a corresponding increase in specific impulse. The increased aerodynamic drag in the elimination section is compensated by the afterburning of the internal cooling curtain in the incoming air flow and the short duration of the TCS in the atmospheric section.

 2. There is an opportunity to make a hydrogen tank, which occupies over 70% of the total volume of tanks, suspended, ie working only in tension, which reduces its weight by 25% when using carbon fiber material.

 3. The absence of jet engines reduces the mass of the structure brought into orbit to acceptable values.

4. Autonomous execution of the LV and the GHG compartment provides:
unification of cargo and manned TCS options;
the possibility of the return of expensive GHGs on an orbital ship in the event of an accident;
expanding the ability to maneuver an orbital ship in orbit by separating the launch vehicle;
the possibility of increasing the launch rate due to the separate functioning of the orbital ship and LV during ground handling and orbital operations;
the possibility of using the experience gained in the creation of orbital ships of the Buran and Shuttle types.

 5. The adopted version of the vertical landing of the LV expands its operational capabilities, providing landing on unprepared sites, including the water surface.

LITERATURE
1. Investigation of the causes of the accident "Titan-4A" and "Delta-3". - "Aerospace", N 38, 1998, ITAR-TASS.

 2. The reliability of rocket technology. - Express information "Astronautics and Rocket Dynamics", N 15, 1990, VINITI.

 3. On the competitiveness of technology created by the NASP program in the world market. - Express information "Astronautics and Rocket Dynamics", N 24, 1990, VINITI.

 4. Concepts of engines of hypersonic aircraft. - Express information "Astronautics and Rocket Dynamics", N 28, 1988, VINITI.

 5. On the development of X-33 and RLV devices. - Express information "Missile and space technology", N 2, 1997, TSNIIMASH.

 6. CFRP in aerospace engineering. - "Aerospace Journal", N 1, 1998. Military parade.

 7. The project "Shuttlecock". - "Bulletin of Aviation and Cosmonautics", N 2-3, 1998, Moscow.

Claims (1)

 A space transport system comprising a tandemly located payload compartment and a single-stage launch vehicle including fuel component tanks and a liquid propellant rocket engine with a central body and modular combustion chambers mounted on the outside of the power frame inside the fairings, characterized in that the said fairings are modular combustion chambers are installed with a gap relative to the specified power frame.

Images