JP2001317406A - Method and device for placing artificial satellite into low earth orbit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new means using air liquefaction to supply a rocket oxidizer for placing a recyclable artificial satellite into a low earth orbit in relation to a field of aerospace crafts. SOLUTION: High-pressure air is extracted from the central part of a turbo fan 20 through an extraction valve 32, and fed to a heat exchanger 36 through a turbine 33. Compressed air flows from the heat exchanger 36 to a LOX generator/separator 38 through a turbine 35. The LOX generator/separator 38 expands the coming air, liquefies it, and separates it to LOX and LN2. The LOX and LN2 are primary chemical components of the air. The newly produced LOX flows to an oxidizer tank 42 for storing the LOX through a turbine 41 until it is used for starting a rocket engine of the spacecraft.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to the field of aerospace vehicles and, more particularly, to a novel use of air liquefaction to provide rocket oxidants for placing reusable satellites in low earth orbit. About the means.

[0002]

BACKGROUND OF THE INVENTION It is known in the art that rockets can be used to take off aircraft and place satellites into earth orbit. One of the most common uses of rockets is the "liquid fuel" rocket. In jet and rocket propulsion engines, fuel mixes with oxidants and burns through nozzles to produce thrust, producing hot gas exiting the engine.
All fuels must be combined with oxidants to burn. At sea level, no separate oxidant is needed because the surrounding air can act as an oxidant. However, at high altitudes, the air is thin and there is no readily available oxidant to burn the fuel.
Therefore, the spacecraft needs to carry its own oxidant.

[0003] The general form of fuel is liquid hydrogen (hereinafter LH).
_Two . ), And a common oxidant is liquid oxygen (LOX). Both LH ₂ and LOX must be cooled to very low temperatures. LOX first compresses the air and then the air at very low temperatures (typically -30
Typically generated by cooling to 0 degrees F). This cryogenic gas is then condensed to a liquid. Since air is not pure oxygen, LOX is separated from liquid air using one of several known methods.

[0004] One of the disadvantages of liquid fuel rockets is that large amounts of oxidizer must be conveyed to burn the fuel. In the LOX-LH ₂ rocket,
The oxidant to fuel ratio is 6: 1. Thus, a typical rocket will have 35 lbs for each pound of payload.
Convey pounds (15.9 kg). The extra weight of LOX has the greatest disadvantage during takeoff when the total weight of the aircraft is maximized. The additional LOX controls the structure and the size of most of the propulsion devices. If the weight of the oxidizer is reduced before the aircraft is taken off, it will greatly reduce the size of the equipment and increase the overall efficiency of the operation of the aircraft.

[0005] In the prior art, it was proposed that spacecraft could generate LOX from ambient air while the aircraft was in flight. This type of device is very advantageous because it allows an aircraft to take off without an initial supply of oxidant. Such a device is not feasible because it is too heavy and inefficient. A major limitation of the prior art devices was that the mechanical system for compressing and cooling the surrounding air was too heavy to keep the aircraft in orbit. Another prior device proposed an aircraft flying at supersonic speed to compress the air entering the entrance. However, supersonic vehicles have many disadvantages and disadvantages. Among them is the generation of shock waves that disrupt the characteristics of the surrounding air into which the supersonic vehicle enters. This configuration cools the air and makes it more difficult to generate LOX.

The present invention provides a method and apparatus for taking off an aircraft without an initial load of oxidizer,
Solves the limitations of the prior art. After takeoff, the aircraft cruises at subsonic speeds and at a given altitude. The spacecraft carries an onboard liquid oxygen generator. Liquid hydrogen fuel for rocket engines is stored in an internal tank. LOX generators use liquid hydrogen fuel to cool incoming air and liquefy gaseous oxygen. Liquid hydrogen has a huge heat capacity to cool the incoming air. Liquid oxygen is stored in tanks until liquid oxygen is required to act as an oxidant in the rocket engine.

[0007]

SUMMARY OF THE INVENTION The present invention includes a method for placing a satellite in low earth orbit. The method of the present invention is intended for use on spacecraft including turbofan and rocket engines. The spacecraft carries the idle load to be put into orbit. In the method of the present invention, the following steps are used. The spacecraft takes off from the runway like a conventional aircraft. During takeoff, the spacecraft uses turbofan engines as power. The spacecraft flies over a predetermined position at a predetermined time. The spacecraft flies at a predetermined altitude at subsonic speed. Compressed air from a turbofan engine is used to generate liquid oxygen from ambient air. Liquid oxygen is stored in an oxidizer tank. When a sufficient amount of liquid oxygen has been generated, the liquid oxygen is used as an oxidant to burn rocket engine fuel.

The present invention includes a structure for generating liquid oxygen in an aircraft. The aircraft includes a storage tank driven by a turbofan engine and containing liquefied hydrogen gas (LH ₂ ). The device for generating liquid oxygen includes an extraction valve located downstream of the compressor stage of the turbofan engine. The extraction valve creates a flow of compressed air. This compressed air is sent to a heat exchanger and cooled. In the present invention, the heat exchanger comprises a duct for flowing compressed air near the outer skin of the aircraft. The temperature of the air at the aircraft surface is very cold and acts as a very efficient cooling mechanism. The cooled air is sent to a condenser. The generator and condenser liquefy the cooled air. The separator is used to separate liquid oxygen from the liquefied air component. Aircraft storage tanks are used to store liquid oxygen.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A novel method and apparatus for using an air liquefaction function to supply an oxidant for use in placing a satellite in low earth orbit is described.
In the following description, for purposes of explanation, particular method steps, element arrangements and structures, and other details are set forth to provide a further understanding of the invention. But,
It will be apparent to one skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known methods and structures have not been described in detail as not to unnecessarily obscure the present invention.

The present invention allows a reusable spacecraft to achieve low earth orbit in a manner that requires the use of a minimum amount of fuel for a given amount of payload. Referring first to FIG. 1, a representative reusable spacecraft 10 employing the present invention is shown. According to the invention, the spacecraft takes off and landes like a conventional airplane. Therefore, the spacecraft has wings 12, horizontal stabilizers 13,
Includes vertical stabilizer 14. The spacecraft includes at least one turbofan engine 20. Turbofan engines are used to power the spacecraft during takeoff. The turbofan engine is modified as described below in connection with FIG.

Referring again to FIG. 1, the spacecraft of the preferred embodiment of the present invention is a two-stage craft. The second stage of the spacecraft includes at least one rocket engine 16. The second stage also contains satellites or other payloads to be placed in earth orbit. The rocket engine is used after takeoff to provide power to put the payload into orbit. Rocket engines are of the liquid fuel type, using liquid oxygen (LOX) as the oxidant. The spacecraft also includes other elements not shown in FIG. Among these elements are the rocket engine 16
There is a fuel tank 18 for holding fuel for use. At takeoff, the fuel tank is almost full. The spacecraft has an oxidizer tank 19, which is almost empty when the spacecraft takes off. The fuel tank 18 and the oxidizer tank are
Connected to rocket engine 16 by a suitable pump (not shown).

Returning to FIG. 1, it should be understood that the configuration shown as spacecraft 10 is for illustration and reference purposes only. FIG. 1 is not meant to be limited to the types of vehicles that can be used with the present invention. In particular, the present invention can be used with different wing and fuselage configurations and different configurations of flight control surfaces. The only limitation is that the spacecraft must have wings with sufficient lift to take off and cruise with the full payload. The preferred embodiment of the present invention provides a turbofan engine to provide thrust during takeoff and early flight missions.
Use the engine.

Referring now to FIG. 2, a representative flight mission overview of a spacecraft using the method of the present invention is shown. A typical flight mission can be broken down into a number of different elements or stages. The various flight missions are indicated by the numbered diamonds in FIG. FIG. 2 illustrates the typical stages of a flight mission included in a preferred embodiment of the method of the present invention. These steps correspond to the steps used in the method of the invention.

[0014] In flight mission phase 1, the spacecraft takes off from the runway like a regular airplane. Takeoff power is provided by a turbofan engine 20. At the time of the spacecraft's takeoff, the spacecraft is carrying not only liquid fuel for rocket engines, but also its payload. However, the spacecraft does not carry rocket engine oxidizers. The oxidant is generated during the third phase of the flight mission, as described below. The absence of oxidizer in the takeoff weight allows the spacecraft to lift large payloads and carry the large payloads to Earth orbit.

Returning to FIG. 2, the second stage is referred to as the "cruise and trail" stage. This stage provides a great deal of flexibility in flight mission planning, allowing the spacecraft to fly in a variety of different types of flight missions. During the second phase, the spacecraft can fly to a predetermined position. This allows the spacecraft to orbit the satellite at a point away from the initial takeoff point. For example, an aircraft can take off and travel far beyond the ocean before the rocket engine starts. This type of flight mission is useful when dangerous payloads are being flown. Also, the spacecraft can walk or wait until a special time before propulsion. This allows the timing of the final trajectory to be specially adjusted.

It is further known that different types of earth orbits are easily obtained when satellites are launched from different locations. For example, if the spacecraft is launched near the equator, the orbit just below the equator is most easily achieved.
This has the advantage of earth rotation speed. Polar trajectories are most easily achieved when the spacecraft is launched from a high altitude. Accordingly, the cruise and trail processes of the present invention allow different types of orbit and flight missions to be achieved. This feature of the invention is not available in the prior art using a rocket launching from a fixed position.

Returning to FIG. 2, in the third stage of the flight mission, the spacecraft generates oxidizer using an on-board LOX generator. The specific structure and operation of the LOX generator will be described below with reference to FIG. In a preferred embodiment of the present invention, the spacecraft flies at subsonic speed. Compressed air is drawn from the turbofan engine. This air is cooled using LH ₂ stored in a rocket fuel tank to generate LOX. LOX generated
Are stored in a spacecraft oxidizer tank.

During the third flight mission, the spacecraft moves at subsonic speed. Supersonic flight is used in the preferred embodiment of the present invention because it is the most efficient. When an airplane flies at supersonic speeds, it generates shock waves. These shock waves, which disturb the flow of the surrounding air, are undesirable and change their properties. In subsonic flight, the air is not disturbed by shock waves. Although the preferred embodiment of the present invention utilizes subsonic flight, those skilled in the art will appreciate that the apparatus of the present invention may be modified to be used at supersonic speeds.

After a sufficient amount of LOX has been generated, the rocket engine is started in flight mission phase 4. This places the spacecraft in orbit above and outside the atmosphere, and in flight mission phase 5 the second stage of the spacecraft leaves and flight mission phase 6
Continue to orbit at a. In flight mission phase 6b, the first stage re-enters the atmosphere, the turbofan engine is restarted, and the spacecraft normally lands in flight mission phase 7 like a conventional airplane.

Next, FIG. 3 shows a schematic configuration showing an apparatus for generating an oxidizing agent in the present invention. Turbo fan
The engine is indicated generally by the reference numeral 20. Turbofan engine 20 includes an inlet duct 22, a high bypass fan 24, a compressor stage 26, a burner stage 28, a turbine and nozzle stage 29. Ambient air enters through an inlet duct 22 and a fan 24 and is split into two parts. Most of the airflow is in the bypass duct 2
Enter 7. The remainder of the air passes through compressor stage 26. In most modern jet engines, the bypass ratio is 6: 1. That is, six parts of air pass through the bypass duct 27 for each part of the air entering the compressor stage 26.

The purpose of the compressor 26 is to compress the incoming air for combustion in the burner. In this way, the air downstream of the compressor 26 has a high pressure. Typically 20% of the air leaving the compressor is injected directly into the fuel burner 28, with 80% bypassing the burner for mixing downstream before the turbine stage 29. In the present invention, the high pressure air bypassing the burner is extracted from the center of the turbofan through the extraction valve 32 and sent to the heat exchanger 36 through the turbine 33. FIG. 3 shows the heat exchanger in schematic form.

The preferred embodiment of the present invention uses a two-stage heat exchanger. In the first stage, the compressed air from the extraction valve 32
It passes through a duct (not shown in FIG. 3) next to the spacecraft hull. When the spacecraft is flying at high altitude, the spacecraft is very cold, typically -30 degrees Fahrenheit.
It will be near the temperature. The duct passes near the outer skin of the wing as well as the spacecraft's fuselage. In the second stage of the heat exchanger, liquid nitrogen (LN2) and liquid hydrogen are used to further cool the incoming air. LN2 is -320 degrees F
, And the temperature of liquid hydrogen is -320 ° F. LN2 is generated as described below.

Compressed air (cooled to around -265 ° F.) from heat exchanger 36 passes through turbine 35
Flow to X generator / separator 38. The LOX generator / separator 38 expands and liquefies the incoming air and converts it to LOX and L
It is separated into a N _2. LOX and LN ₂ is a primary chemical constituent of air. The newly created LOX flows through a turbine 41 to a stored oxidizer tank 42 until it is used to start a spacecraft rocket engine.

As mentioned above, the LOX generator also has a LN
Bring _two . LN ₂ is returned to heat exchanger 36 and used to pre-cool the incoming compressed air from turbine 33. After the nitrogen passes through the heat exchanger, the nitrogen becomes a gas. The gaseous nitrogen is injected back into the burner of the engine under pressure. There, the gaseous nitrogen mixes the combustion products and enters the turbine.

Returning again to FIG. 3, the present invention makes use of LH ₂ from the air liquefaction process to increase the operating efficiency of turbofan engine 20. After LH ₂ is used in an air heat exchanger, LH ₂ is heated and expands into a gas. This gaseous hydrogen (GH ₂ ) passes through turbine 45 and is directed to a turbofan engine. The gaseous hydrogen is then directed to the burner stage 27 of the engine. GH ₂ fuel is mixed with 20% of the remaining air combusted to drive the turbofan engine. In this way, the hydrogen used is not lost and the overall operating efficiency of the turbofan engine 20 and the entire spacecraft is improved. FIG. 4 shows a detailed structure of the configuration of the present invention. The elements of the structure are shown in schematic form.

The description of the invention has been made with reference to specific method steps, structures, and arrangements for placing a satellite in low earth orbit. It will be understood by those skilled in the art that the foregoing description is illustrative only, and that various changes and modifications may be made to the invention without departing from the spirit and scope of the invention. . The full scope of the invention is:
It is defined and limited only by the claims.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a typical reusable spacecraft employing the present invention.

FIG. 2 is a diagram of a typical flight mission plan outline for a spacecraft employing the method of the present invention.

FIG. 3 is a schematic diagram of a liquid oxygen generator of the present invention.

FIG. 4 is a more detailed schematic diagram of the liquid oxygen generator of the present invention.

 ──────────────────────────────────────────────────続 き Continuing the front page (72) Inventor Dana Andrews 98134 Seattle, Washington, USA, First Avenue South 900, Suite 402

Claims (9)

[Claims] 1. A method for generating a liquid component from ambient air, comprising employing an aircraft, the aircraft including at least one turbofan engine, and causing the aircraft to fly at subsonic speed, a predetermined altitude. Generating liquid components from the ambient air, wherein the liquid components consist of one or more of the group of liquid oxygen and liquid nitrogen, isolating the liquid components, and separately placing each liquid component in the aircraft tank. A method consisting of storing. 2. The method of claim 1, wherein said aircraft is a spacecraft. 3. The method of claim 1, further comprising generating liquid nitrogen from ambient air and storing the liquid nitrogen in the spacecraft tank. 4. A method for extracting compressed air downstream from a compressor of the turbofan engine, wherein the compressed air is cooled using one or more types of coolants from the group consisting of liquid hydrogen, liquid oxygen, and liquid nitrogen. And liquefying, wherein each type of coolant is used in a process stored in the spacecraft tank and further comprises separating liquid oxygen from liquefied compressed air.
The method described in. 5. The method according to claim 1, wherein said generating step comprises extracting compressed air downstream from a compressor of said turbofan engine, a heat exchanger, and at least one liquid element from the group consisting of liquid hydrogen, liquid oxygen, and liquid nitrogen. Cooling and liquefaction of said compressed air using, wherein each liquid component is separately stored in a tank of said aircraft and separating at least one liquid component from the group consisting of liquid oxygen and liquid nitrogen from said liquefied compressed air The method of claim 1 comprising: 6. Flying an aircraft at subsonic speed; extracting air downstream from a compressor stage of a turbofan engine of the aircraft; and receiving the compressed air into the aircraft; And cooling the compressed air sufficiently to liquefy the compressed air, and separating liquid oxygen (LOX) from the liquefied air. 7. Flying an aircraft at subsonic speed; receiving ambient air into said aircraft; cooling said air sufficiently to liquefy said air; liquid oxygen (LOX) and liquid nitrogen ( LN ₂ ). A method for generating a coolant, comprising separating at least one liquid component from the group consisting of LN ₂ ) from said liquefied air. 8. An apparatus for producing one or more liquid components from the group consisting of liquid oxygen (LOX) and liquid nitrogen (LN ₂ ) in a service aircraft including at least one turbofan engine, said liquid component comprising: One is liquefied hydrogen gas (LH ₂ ), an extraction valve located downstream of the compressor stage of the turbofan engine, and a heat exchanger in fluid communication with the extraction valve and using the LH _2. A storage tank in fluid communication with the heat exchanger. 9. The apparatus of claim 8, wherein said heat exchanger comprises a plurality of ducts for passing a flow of compressed air near a skin of said aircraft and cooling said flow of compressed air.