GB2559044A

GB2559044A - A vertical take-off vehicle

Info

Publication number: GB2559044A
Application number: GB1720720.0A
Authority: GB
Inventors: Stephen Bell Ian
Original assignee: Individual
Current assignee: Individual
Priority date: 2017-12-12
Filing date: 2017-12-12
Publication date: 2018-07-25
Also published as: GB201720720D0

Abstract

A vertical take-off vehicle, rocket or VTOL has an elongate body, a storage container 356, 358 suitable for storing propellant, a combustion chamber 366 in which the propellant is burnt to generate exhaust gases, a nozzle (370, fig 6) connected to the combustion chamber through which exhaust gases can be emitted to propel the vehicle upwards and a balloon 382 mounted on the body of the vehicle in a folded state. When deployed, the balloon is inflated by the exhaust gases. Preferably the balloon may be maintained in its inflated state by the exhaust gases. The nozzle may extend into, or towards, the inner space of the balloon when the balloon is in its inflated state. The vehicle may be capable of controlling the rate at which the combustion emits exhaust gases during the inflation of the balloon and to maintain the balloon in its inflated state.

Description

(71) Applicant(s):

Ian Stephen Bell

Pembroke Close, SUNNINGHILL, Berkshire, SL5 0ΑΒ, United Kingdom (72) Inventor(s):

Ian Stephen Bell (56) Documents Cited:

US 3508724 A US 3168266 A (58) Field of Search:

INT CL B64B, B64D, B64G, F42B

Other: EPODOC, WPI, Internet, Patents fulltext (74) Agent and/or Address for Service:

Ian Stephen Bell

Pembroke Close, SUNNINGHILL, Berkshire, SL5 0ΑΒ, United Kingdom (54) Title of the Invention: A vertical take-off vehicle

Abstract Title: Rocket with balloon for fall retardation (57) A vertical take-off vehicle, rocket or VTOL has an elongate body, a storage container 356, 358 suitable for storing propellant, a combustion chamber 366 in which the propellant is burnt to generate exhaust gases, a nozzle (370, fig 6) connected to the combustion chamber through which exhaust gases can be emitted to propel the vehicle upwards and a balloon 382 mounted on the body of the vehicle in a folded state. When deployed, the balloon is inflated by the exhaust gases. Preferably the balloon may be maintained in its inflated state by the exhaust gases. The nozzle may extend into, or towards, the inner space of the balloon when the balloon is in its inflated state. The vehicle may be capable of controlling the rate at which the combustion emits exhaust gases during the inflation of the balloon and to maintain the balloon in its inflated state.

1/5

2/5

P

13¼

3/5

4/5

5·Τ

5/5 'iS’e

A vertical take-off vehicle

The present invention relates to a vertical take-off vehicle, such as a rocket, and a method for returning a vertical take-off vehicle or a part of a vertical take-off vehicle such as a stage of a multistage rocket, to the surface of the earth without damage.

A vertical take-off vehicle typically comprises at least one rocket and often a plurality of rockets which are connected to each other to form a multi stage rocket.

A typical rocket comprises an elongate body which is substantially tubular in shape in which is stored a chemical propellant. The propellant can be a solid propellant, a liquid propellant ora combination of the two. The propellant is burnt in a combustion chamber with the exhaust gases generated by the combustion being emitted at high speed from the base of the elongate body through a nozzle.

If the rocket is powered by a solid propellant, typically, it will comprise a solid propellant comprising a mixture or combination of a solid fuel and oxidant which are stored in a container. The container also forms the combustion chamber, as the solid propellant is burnt within the container, to create exhaust gases. The exhaust gases exit the container via a nozzle connected to an end of the container which controls the speed and direction in which the exhaust gases are emitted. It will be appreciated that of the solid propellant contained small pellets or is in a powdered form, it can be pumped or otherwise transported from a storage container into a separate combustion chamber.

If the rocket is powered by a liquid propellant, typically, it will comprise a liquid fuel and oxidant which are stored separately within tanks inside of the tubular body. The liquid fuel and oxidant are either mixed together and then pumped into a combustion chamber or, alternatively, are pumped separately into the combustion chamber where they subsequently mix. Once the liquid fuel and oxidant are inside of the combustion chamber, they are burnt to form exhaust gases. The exhaust gases exit the container via a nozzle which is attached to a side of the combustion chamber and which controls the speed and direction in which the exhaust gases are emitted. It will be appreciated that the liquid fuel and oxidant can be stored in a storage container already pre-mixed. The mixture is then pumped into a combustion chamber prior to it being burnt.

If the rocket is powered by a combination of a liquid propellant and solid propellant, then the liquid part can mixed with the solid part, which can be a solid lump, a plurality of smaller pellets or a powder, prior to being burnt within a combustion chamber. Alternatively, the combination propellant can be a liquid with tiny solid particles mixed in it. Such a mixture can be pumped around the rocket in the same manner as a liquid.

It will be appreciated that a rocket, whether powered by a liquid propellant, a solid propellant or a combination, may have more than one combustion chamber. Whilst it is possible for a rocket with multiple combustion chambers to utilise a single nozzle or a jointly a number of common nozzles, typically each combustion chamber will have its own nozzle. Furthermore, it will be appreciated that, whilst typically each combustion chamber comprises a single nozzle, it is possible for each combustion chamber to comprise a number of nozzles.

A multistage rocket comprises several stages which are attached to each other to act as a combined rocket. Each stage of a multistage rocket typically comprises an individual rocket having its own rocket engine and propellant. There are several types of stages in a multistage rocket. For example, there can be a serial stage which is attached on top of or below another stage. Alternatively, there can be a parallel stage which is attached alongside or in parallel to another stage. Such parallel stages are often used as booster rockets. A multistage rocket may consist of serial stages only, or parallel stages only, or a combination of the two.

The rocket engines in each stage of a multi stage rocket can be activated at the same time as other stages (for example booster rockets being activated with a main rocket) or prior to or in succession with the activation of other stages (for example where one stage is mounted on another stage and therefore cannot be activated until the lower stage has been jettisoned).

Once a stage has use up its propellant, it is typically ejected from the rest of the multi stage rocket to reduce the weight of the rest of the multistage rocket which is travelling into space. Such stages are used to assist in the propelling the multistage rocket during the early part of the flight into space.

Figure 1 shows a multistage rocket prior to launching comprising two serial stages 100,102, an upper serial stage 100 which is mounted on and rigidly attached to a lower serial stage 102. Each stage 100,102 comprises a liquid propellant stored in tanks (not shown), a mixer and pump (not shown), a combustion chamber 104,106 and a nozzle 108,110. A pay load (not shown) is mounted inside a top capsule 112 mounted on and rigidly attached to the top of the upper serial stage 100. A first set of explosive bolts (not shown) are mounted on the top of the lower serial stage 102 adjacent the location where the upper serial stage 100 is attached to the lower serial stage 102. Detonation of the first set of explosive bolts disconnects the upper serial stage 100 from the lower serial stage 102. A second set of explosive bolts (not shown) are mounted on the top of the upper serial stage 100 adjacent the location where the top capsule 112 is attached to the upper serial stage 100.

Detonation of the second set of explosive bolts disconnects the upper serial stage 100 from the top capsule 112.

When the multistage rocket of Figure 1 is launched, the lower serial stage 102 only is activated. When activated, the mixer and pump draws liquid propellant from the tanks into the mixer and pump and then injects it into the combustion chamber 106 at a high flow rate. Once the liquid propellant enters the combustion chamber 106 it is ignited to generate a large quantity of gas. The gas exits the combustion chamber 106 through the nozzle 110 and propels the multi stage rocket upwards into the atmosphere away from the surface 116 of the earth in well-known manner. As the upper serial stage 100 is rigidly attached to a lower serial stage 102, the multistage rocket travels as a single unit. The engine of the upper stage 100 remains deactivated whilst it is attached to the lower stage 102.

After a predetermined period of time, the liquid propellant in the lower stage 102 runs out. At this point, the first set of explosive bolts are detonated. The upper serial stage 100 then becomes detached from the lower serial stage 102. Then the engine of the upper serial stage 100 is activated. When activated, the mixer and pump in the upper stage 100 draws liquid propellant from the tanks into the mixer and pump and then injects it into the combustion chamber 104 at a high flow rate. Once the liquid propellant enters the combustion chamber 104 it is ignited to generate a large quantity of gas. The gas exits the combustion chamber 104 through the nozzle 108 and propels the upper stage 100 further upwards into the atmosphere away from the lower stage 102 as shown in Figure 2. The upper stage 100 will continue upwards until it has entered space where it will deposit the pay load into space. The lower stage 102 then drops back towards the earth's surface 116 under the force of gravity.

In order to reduce the cost of launching a vertical take-off vehicle, it is desirable to reuse part or all of a vertical take-off vehicle. In order to reuse part or all the vertical take-off vehicle, the part or all of the vertical take-off vehicle needs to be able to return the surface of the earth without being damaged. In particular, where the vertical take-off vehicle is a multistage rocket, it is desirable to return the stages of the rocket which are jettisoned during the ascent of multistage rocket, for example, any booster rockets or the first stage of a multistage rocket, safety to the surface of the earth without damage. Several systems have been developed to enable jettisoned stages to be returned safely without damage.

A first example is shown in Figure 3 in relation to a first lower stage 102 of the two stage multistage rocket shown in Figures 1 and 2. A folded parachute 118 is mounted in the end of the lower stage 102 which is remote from the combustion chamber 106 and nozzle 110. After the first set of explosive bolts are detonated and the upper serial stage 100 is detached from the iower serial stage 102, the parachute 118 is deployed, causing the canopy 120 to open. Cables 122 attach the canopy

120 to the housing of the lower stage 102. The parachute 118 slows the lower stage 102 as it falls back to earth under the force of gravity. The problem with design is that the parachute 118 only slows the fall producing a controlled fall. The lower stage 102 still strikes the surface 116 of the earth when it makes contact with the surface 116. The rate at which the lower stage 102 falls, and hence the size of the impact can be decreased when it hits the surface 116 of the earth, can be reduced by increasing the size of the canopy 120 of the parachute 118 or the number of parachutes 118. However, increasing the size of the canopy 120 of the parachute 118 or the number of parachutes 118 makes the falling stage 102 more subject to interference from cross winds. A further problem is that the combustion chamber 106 and nozzle 110 face towards the surface 116 of the earth as the stage approaches the surface. This is undesirable as these are the most complex and delicate parts of the stage 102 and most likely to suffer damage if incorrectly impacted on the surface 116 due to a malfunction of the system. Furthermore, as it is complex, it would be the most expensive part to repair or replace, assuming the stage 102 is reusable. As such, a frame or protective shield (not shown) has to be provided which surrounds the combustion chamber 106 and nozzle 110 to provide protection when the lower stage 102 impacts the surface 116 of the earth.

A second example is shown in Figure 4 in relation to the first lower stage 102 of a two stage multistage rocket shown in Figures 1 and 2. As the lower stage falls 102 towards the surface 116 of the earth, the orientation of the lower stage 102 is controlled so that the nozzle 110 continues to point towards the surface 116 of the earth. Such control is provided by the use of fins (not shown) which control the flow of air over the lower stage 102 as it falls towards the surface 116 of the earth. As the lower stage 102 approaches the surface 116, the lower stage 102 is activated so that exhaust gases are emitted from the nozzle 110 and directed towards the surface 116 of the earth. The force of the exhaust gases is controlled so that the lower stage 102 is brought slowly down unto the surface 116 of the earth. However, as the combustion chamber 106 and nozzle 110 face towards the surface 116 of the earth as the stage 102 approaches the surface 116, a set of legs 130 need to be deployed on the lower stage 102 on which the lower stage 102 lands in order to prevent the combustion chamber 106 and nozzle 110 making contact with the surface 116 and becoming damaged. Such a system requires a significant amount of propellant to be available to provide sufficient force from the exhaust gases being emitted from the nozzle 110. This increases the initial weight of the lower stage 102 when it is launched. Furthermore, it requires the addition of the legs 130 and control systems to ensure that the legs 130 deploy correctly.

Figure 5 shows a hot air balloon. A typical air balloon comprises an envelope 134 in the form of a bag which has an entrance into a cavity 140 formed by the bag 134 when the bag 134 is inflated. A basket 132 is typically attached to the periphery of the entrance by a series of ropes 136 which results, during the normal operation of the hot air balloon, in the entrance of the bag 134 facing downwardly. Mounted inside of the basket 132 is a burner 138 which is connected to a gas cylinder 142 in which is stored a flammable gas. The burner 138 faces toward the entrance of the bag 134. Upon activation of the burner 138, gas is drawn from the cylinder 142 into the burner 138 and then directed towards the entrance. As the gas exits the burner 138, it is ignited, resulting in a large flame which is directed towards and through the entrance of the bag 134. The burning gas heats up the air inside of the bag 134 which reduces it density. As the air in the bag 134 is lighter than the air surrounding bag 134, it causes the bag 134, together with the basket 132 and its contents to float.

By controlling the heat of the air inside of the bag 134, by controlling the amount of gas burnt and the frequency of when it is burnt, the height of the hot balloon above the surface 116 of the ground can be controlled.

The object of the present invention is to provide an alternative system and method of returning part or all of a vertical take-off vehicle safety to the surface of the earth after being used.

According to a first aspect of the present invention, there is provided a vertical take-off vehicle comprising:

an elongate body;

at least one storage container in which a propellant can be stored;

at least one combustion chamber in which the propellant can be burnt to generate exhaust gases;

at least one nozzle connected to the at least one combustion chamber through any exhaust gases can be emitted to propel the vertical take-off vehicle upwardly;

at feast one balloon mounted on and attached to the body in a first folded state which is capable of expanding from the first folded state to a second inflated state when deployed;

wherein, when exhaust gases are being emitted from the at least one nozzle, upon deployment of the at least one balloon, the at least one balloon expands from its first folded state to its second inflated state using the exhaust gases emitted from the at least one nozzle.

According to a second aspect of the present invention, there is provided a vertical take-off vehicle comprising:

an elongate body;

at least one storage container in which a propellant can be stored;

at least one combustion chamber in which a propellant can be burnt to generate exhaust gases;

at least one nozzle connected to the at least one combustion chamber through any exhaust gases can be emitted to propei the vertical take-off vehicle upwardly;

at least one balloon mounted on and attached to the body in a first folded state which is capable of expanding from the first folded state to a second inflated state when deployed;

wherein, when exhaust gases are being emitted from the at least one nozzle and the at least one balloon is in its second inflated state after deployment, the at least one balloon is maintained its second inflated state using the exhaust gases emitted from the at least one nozzle.

It wili be appreciated that the storage container and the combustion chamber may be the same container if the propellant is burnt within the storage container.

it will be appreciated a rocket may contain a single combustion chamber or several combustion chambers. Whilst each combustion chamber is likely to contain a single nozzle, it will be appreciated that a combustion chamber may contain several nozzles. A single balloon may be used for each rocket, drawing some or all of the exhaust gases from the nozzle or plurality nozzles if there are more than one. Alternatively, the rocket comprises several balloons which are inflated using some or all of the exhaust gases from the nozzle or plurality nozzles if there are more than one.

Three embodiment of the present invention will now be described with reference to the attached drawings.

Figure 1 shows a side view of a prior art multi stage rocket;

Figure 2 shows a side view of the trajectory of a multistage rocket;

Figure 3 shows a side view of the first stage of a multistage rocker landing using a parachute;

Figure 4 shows a side view of a multistage rocket landing using the rocket engine;

Figure 5 shows a vertical cross section of a hot air balloon;

Figure 6 shows a vertical cross section of a multistage rocket prior to launch according a first embodiment of the present invention;

Figure 7 shows a vertical cross section of the first stage of the multistage rocket of Figure 1 with the hot air balloon deployed;

Figure 8 shows a vertical cross section of the lower part of the first stage of the multistage rocket prior to launch in accordance with a second embodiment; and

Figure 9 shows a vertical cross section of the lower part of the first stage of the multistage rocket prior to launch in accordance with a third embodiment.

A first embodiment of the present invention will now be described with reference to Figures 6 and 7.

Figure 6 shows a multistage rocket 300 prior to being launched. The multistage rocket 300 comprises a first stage 302 and a second stage 304, the first stage 302 being mounted on top of the second stage 304. Mounted on top of the first stage 302 is a payload container 306.

The first stage 302 comprises an outer housing 308 which is tubular in shape and surrounds a longitudinal axis 310. The tubular housing 308 has circular cross section and is of uniform diameter along the majority of its length. The top end 312 of the housing 308 comprises a wall which extends perpendicularly to the longitudinal axis 310. The bottom end 314 tapers inwardly.

Mounted inside of the housing 308 are two storage tanks 316, 318 which are located is series inside of the housing 308. The first tank 316 is capable of holding a liquid fuel. The second tank 318 is capable of holding a liquid oxidant. Each tank 316, 318 is connected to a combined mixer and pump 320 via a pipe 322, 324. The mixer/pump 320 is capable of drawing the liquid fuel from the first tank 316 and liquid oxidant from the second tank 318, mixing them together and then pumping the mixture into a combustion chamber 326 via a third pipe 328. The combustion chamber 326 is connected to a thrusto conical nozzle 330 mounted on the lower side of the combustion chamber 326 via a throat 332, the narrow end of the nozzle 330 connecting to the throat 332. The combustion chamber 326 is mounted inside of the aperture formed by the tapered lower section 314 of the housing 308 with the nozzle 330 projecting in a direction which is symmetrically aligned with and parallel to the longitudinal axis 310 of the housing 308. The nozzle 330 is manufactured in a one piece construction. The mixer/pump 320, the combustion chamber 326 and the nozzle 330 form a rocket engine.

The second stage 304 also comprises an outer housing 350 which is tubular in shape and surrounds a longitudinal axis 310 which is co-axial with the longitudinal axis of the first stage 302. The tubular housing 350 has a circular cross section of uniform diameter along the majority of its length. The diameter of the tubular housing 350 of the second stage 304 is greater than that of the first stage 302. The top end 352 of the housing 350 tapers inwardly. Similarly, the bottom end 354 tapers inwardly.

Mounted inside of the housing 350 are two storage tanks 356, 358 which are located is series inside of the housing 350. The first tank 356 is capable of holding a liquid fuel. The second tank 358 is capable of holding a liquid oxidant. Each tank 356, 358 is connected to a combined mixer and pump

360 via a pipe 362, 364. The mixer/pump 360 is capable of drawing the liquid fuel from the first tank 354 and liquid oxidant from the second tank 356, mixes them and pumps the mixture into a combustion chamber 366 via a third pipe 368. The combustion chamber 366 is connected to a thrusto conical nozzle 370 mounted on the lower side of the combustion chamber 366 via a throat 372, the narrow end of the nozzie 370 connecting to the throat 372. The combustion chamber 366 is mounted inside of the aperture formed by the tapered lower section 354 of the housing 350 with the nozzle 370 projecting in a direction which is symmetrically aligned with and parallel to the longitudinal axis 310 the housing 350. The mixer/pump 326, the combustion chamber 366 and the nozzle 370 form a rocket engine.

The nozzle 370 is manufactured in two parts, an upper section 374 which is connected to a lower section 376 via a frangible section 378. Both the upper and lower sections 374,376 are thrusto conical in shape. An explosive separator 380 is attached to the frangible section 378 which, when activated, detonates and breaks the frangible section 378.

A folded balloon 382 is mounted on the second stage 304. The balloon 382 is tubular in shape [as best seen in Figure 7 where it is shown in an inflated state} having an opening 384 at a top first end 388 (as seen in Figure 7) which is narrow in cross section (Arrow B) and a second opening 386 at a second lower end 390 which is narrow in cross section (Arrow A). When the balloon 382 is inflated, the size of the area of the cross section of the baiioon 382 increases significantly along the length of the balloon 382 from the first end 388 to the centre (indicated by Arrow C) and then decreases from the centre to the second end 390. The shape of the cross section of the inflated balloon 382 in a direction perpendicular to a longitudinal axis of the tubular balloon which axis runs from the first end 388 to the second end 390, is circular. It will be appreciated that other shapes of balloon can be utilised.

The first end 388 is connected to the lower section 376 of the nozzie 370. The second end 390 is connected directly to bottom tapered section 354 of the housing 350. The balloon 382 is folded so that it consist of a series pleats 392. The pleats 392 are tightly packed so that no gaps are left between the pleats 392 of the folded balloon 382. The folded balloon 382 surrounds the longitudinal axis 310 of the lower stage 304 in a symmetrica! manner. The pleats 392 of the folded balloon 382 form a passageway 394 through which the nozzle 370 extends, the pleats 392 surrounding the nozzle 370. The whole of the folded balloon 382 is located above (as shown in Figure 6) the exit of the nozzie ie the whole of the folded balloon 382 is located upstream of the exit of the nozzie 370. Also, both ends of the folded balloon 382 are attached to the stage 304 upstream of the exit of the nozzle 370.

The payload container 306 comprises a conical wall 396 connected to a tubular wall 398 of circular cross section. The payload container 306 is symmetrical around the longitudinal axis 310 of the first stage 302. The radial wall 312 of the first stage 302 forms the base of the payloads container 306.

The payload container 306 is mounted the first stage 302 using a first set of explosive bolts (not shown) so that it is rigidly attached to the first stage 302. Detonation of the first set of explosive bolts disconnects the upper first stage 302 from the payload container 306. A second set of explosive bolts (not shown) are mounted on the top of the lower second stage 304 adjacent the location where the upper first stage 302 is attached to the second stage 304. Detonation of the second set of explosive bolts disconnects the upper first stage 302 from the lower second stage 304.

In order to prepare the multistage rocket for launch, a payload 400 is place inside of the payload container 306. All of the tanks in the first and second stages 302, 304 are filled with liquid fuel or oxidant as appropriate.

When the multistage rocket of Figure 6 is launched, the second lower stage only 304 is activated. When activated, the mixer and pump 360 of the second stage 304 draws liquid propellant from the tanks 356, 358 into the mixer and pump 360 and then injects it into the combustion chamber 366 at a high flow rate. Once the liquid propellant enters the combustion chamber 366 it is ignited to generate a large quantity of gas. The gas exits the combustion chamber 366, through the nozzle 370 and exits in a downward direction (as viewed in Figure 6), downstream of the exit of the nozzle 370 and propels the multi stage rocket upwards into the atmosphere away from the surface 116 of the earth in weil-known manner. As the payload container 360 is rigidly attached the upper first stage 302 which in turn is rigidly attached to the lower second stage 304, the multistage rocket travels upwardly as a single unit. The engine of the first stage 302 remains deactivated whilst it is attached to the second stage 304.

After a predetermined period of time, when the majority of the liquid propellant in the second stage 304 has been burnt, the second stage 304 is deactivated so that exhaust gases cease to be emitted from the nozzle 370 of the second stage 304. At this point, the second set of explosive bolts are detonated. The upper first stage 302 then becomes detached from the lower second stage 304. Then the rocket engine of the upper first stage 304 is then activated. When activated, the mixer and pump 320 in the first stage 302 draws liquid propellant from the tanks 316, 318 into the mixer and pump 320 and then injects it into the combustion chamber 326 at a high flow rate. Once the liquid propellant enters the combustion chamber 326 it is ignited to generate a large quantity of gas. The gas exits the combustion chamber 326 through the nozzle 330 and propels the upper stage 302 further upwards into the atmosphere away from the lower stage 304 in the same manner as shown in Figure 2. The upper stage 302 will continue upwards and until it has entered space. When in located in space in a stable orbit, the rocket of the first stage 302 is deactivated so that exhaust gases cease to be emitted from the nozzle 330 of the first stage 302. The first set of explosives bolts are then detonated detaching the payload container 306 from the first stage 302. Once the payload container 306 is detached from the first stage 302, the payload 400 can be deployed into space.

After the second stage 304 has been detached from the first stage 302 during launch, the lower second stage 304 will commence dropping back towards the earth's surface 116 under the force of gravity. When the second stage 304 has dropped to a pre-determined altitude, the balloon 382 is deployed. This is achieved by the detonation of the explosive separator 380 connected to the frangible section 378 of the nozzle 370. When the explosive separator is detonated, the frangible section breaks 378, separating the nozzle 370 into two sections 374, 376. At the same time, the rocket engine of the second stage 304 is reactivated causing exhaust gases to be emitted from the upper section 374 of the nozzle 370. The exhaust gases entrain the lower section 376 of the nozzle 370 and force it away from the first section 374 in a downward direction (as shown in Figure 6), downstream of the exit of the upper section 374 of the nozzle 370, The explosive detonator 380 can also be arranged so that, when exploded, it assists in forcing the lower section 374 away from the upper section 374, in a downstream direction. As such, the folded balloon begins 382 to inflate with one end 388 moving away from the other end 390. As the end 388 moves away, the balloon 382 surrounds the jet of the exhaust gases being emitted from the upper section 374 resulting in the exhaust gases being injected into the internal cavity 402 of the balloon 382. As such, the exhaust gases cause the balloon 382 to expand until it becomes fully inflated. The exhaust gases are then used to maintain the balloon 382 in its inflated state. During the inflation of the balloon 382 and the maintenance of the inflated balloon 382, the mixer and pump 360 is controlled so that the amount of liquid propellant entering the combustion chamber 366 and hence the amount of exhaust gases exiting the nozzle 370 is controlled so that the inflation of the balloon 382 and its maintenance is optimised. Apertures 404 are formed through the side wall of the balloon 382 which, in addition to the hole 384 formed in the end 388 of the balloon 382, assist in controlling the exhaust gases inside of the balloon 382.

Once inflated, the balloon 382 creates a resistance as air flows past it as the second stage 304 and inflated balloon 382 fall towards the surface 116 of the earth causing the second stage 304 and the balioon 382 to rotate until the balloon 382 is located above the second stage 304 as shown in Figure 7 as the second stage 304 and balloon 382 fall towards the surface 116 of the earth (the inflated balloon 382 acts on the second stage 304 in a similar manner as the feathers act on a shuttle cock). This rotation is further aided by the balloon 382 being filled with hot exhaust gases which causes the air within the balloon the less dense than the surrounding air and therefore the balloon 382 to be lighter than the surrounding air.

As the balloon 382 is inflated and is maintained in an inflated state, the friction of air passing around the balloon 382 also causes the fall second stage 304 to be slowed. Once the balloon 382 is inflated and the second stage 304 is orientated as shown in Figure 7, the balloon 382 and second stage 304 acts in the same manner as a hot air balloon, with the combustion chamber 366 and nozzle 370 acting as the burner. The balloon 382, inflated with hot exhaust gases, can be used to either slow the fall of the second stage 304, stop it from falling, causing the second stage 304 to float a constant height, or can cause it rise. By controlling the amount of exhaust gases entering into the balloon 382, either by reducing or increasing the flow of the exhaust gases entering the balloon 382 and/or generating exhaust gases on an intermittent basis, the height of the second stage 304 above the surface 116 of the earth can be controlled. As such, the second stage 304 can be brought down to the surface 116 the earth in a controlled manner. Furthermore, when the second stage 304 makes contact with the surface 116 of earth, the combustion chamber 366 and nozzle 370 will be facing upwards as shown in Figure 7 and therefore are less likely to be damaged upon impact.

When the balloon 382 is initially inflated and the second stage 304 and balloon 382 begin to slow down (through friction and the use of hot exhaust gases within the balloon 382), the pressure in the balloon 382 may need to be kept slightly higher than when the balloon 382 and second stage 304 are acting fully like a hot air balloon in order to maintain the shape of the balloon 382.

It will be appreciated that, instead of connecting the balloon directly to the housing 350 of the second stage 304, the balloon 382 can be attached indirectly to the housing rocket using ropes, cables or netting, or other similar types of connectors.

Furthermore, it will be further appreciated that the second end 390 can be connected directly to the upper section 374of the nozzle instead of the bottom tapered section 354 of the housing 350. The first end 388 would remain connected to the lower section 376 of the nozzle 370. The balloon 382 would function in the same manner.

It will be further appreciated that, during the separation of the first and second stages 302, 304 and/or the deployment of the balloon, the rocket engine of the second stage 304 can remain activated at all times through-out the separation of the two stages and/or deployment of the balloon 282, the rocket engine being controlled to control the amount of exhaust gases being emitted.

A second embodiment will not be described with reference to Figure 8. Where the same features are used in the second embodiment which were used in the first embodiment, the same reference numbers are used. The second is embodiment is the same as the first embodiment except for the method that the balloon 382 is mounted on the second stage 304 when it is folded.

In the first embodiment, the balloon 382, when folded, is connected to the nozzle 370 at one end 388 and the housing 350 at the other end 390. However, the nozzle 370, when emitting exhaust gases, is subjected to a great deal of vibration and heat. Such vibration and heat will apply a large amount of stress on the frangible section 378. This could result in the frangible section braking 378 resulting in the early deployment of the balloon 382 which in turn would cause a failure in the launch of the multistage rocket. Therefore, in the second embodiment, the first end 388 of the balloon 382 is connected to an extended section 406 of the housing 350 located below the lower tapered section 354. The second end 390 is connected to bottom tapered section 354 of the housing 350, The nozzle 370 of the second stage 304 is manufactured in a one piece construction thus avoiding the problem associated with having a frangible section 378, The extended section 406 is connected to bottom tapered section 354 via a frangible section 408. An explosive separator 410 is attached to the frangible section 408 which, when activated, detonates and breaks the frangible section 408.

The balloon 382 is inflated and used in the same manner as in the first embodiment, the frangible section 408 being broken upon detonation of the explosive separator 410. When broken the extended section 406 is urged in the direction of the exhaust gases, downstream of the nozzle 370. The extended section 406 comprises a ring 412 which surrounds the hole 384 at the end 388 of the tubular balloon 382.

A third embodiment will not be described with reference to Figure 9. Where the same features are used in the third embodiment which were used in the first embodiment, the same reference numbers are used. The third embodiment is the same as the first embodiment except for the method that the balloon 382 is mounted on the second stage 304 when it is folded.

In the first embodiment, the baiioon 382 is connected to the nozzle 370 at one end 388 and the housing 350 at the other end 390. However, the nozzle 370, when emitting exhaust gases, is subjected to a great deal of vibration and heat. Such vibration and heat will apply a large amount of stress on the frangible section 378. This could result in the frangible section 378 braking resulting in the early deployment of the baiioon 382 which in turn would cause a failure in the launch of the multistage rocket. Therefore, in the third embodiment, the first end 388 of the balloon 382 is not connected to anything. The second end 390 is connected to bottom tapered section 354 of the housing 350. The nozzle 370 of the second stage 304 is manufactured in a one piece construction thus avoiding the problem associated with having a frangible section 378. The balloon 382 is maintained in its folded state by the use of a series of cables 414 which wrap around the pleats 392 of the folded balloon 382 in its folded state. A series of explosive devices 416 are attached to the cables 414 which, when activated, detonate and break the cables 416.

The balloon 382 is inflated and used in the same manner as in the first embodiment. When the cables 414 are broken, the free end 388 is urged in the direction of the exhaust gases. The end 388 of the balloon 382 is sufficiently strong enough to prevent the balloon 382 from ripping. However, it will be appreciated that a metal ring (not shown) could be attached to the first end 388 of the balloon to reinforce the material of the balloon 382 around the hole 384.

will be appreciated that a device can be fitter to the free end 388 of the balloon which, once the balloon 392 has been deployed, reduces the diameter of the hole 384 to reduce the amount of gases which can be emitted through the hole 384.

Whilst the three embodiments are described in relation to a rocket having a liquid propellant, the same principles applied a rocket having a solid propellant or a combination of a liquid and solid propellant.

Claims

1 A vertical take-off vehicle comprising,' an elongate body;

at least one storage container in which a propellant can be stored;

2 A vertical take-off vehicle as claimed in claim 1 wherein, when exhaust gases are being emitted from the at least one nozzle and the at ieast one balloon is in its second inflated state after deployment, the at least one balloon is maintained its second inflated state using the exhaust gases emitted from the at least one nozzle.

3 A vertical take-off vehicle comprising:

an elongate body;

at least one storage container in which a propellant can be stored;

4 A vertical take-off vehicle as claimed in any of claims 1 to 3 wherein the at least one balloon is attached directly to the housing.

5 A vertical take-off vehicle as claimed in any of claims 1 to 3 wherein the balloon is attached indirectly to the housing.

6 A vertical take-off vehicle as claimed in claim 5 wherein the at least one balloon is attached via indirectly using cables, ropes, or netting or any combination thereof.

7 A vertical take-off vehicle as claimed in any of the previous claims wherein the at least one balloon is attached to the housing upstream of the exit of the nozzle.

8 A vertical take-off vehicle as claimed in any of the previous claims wherein the at least one balloon extends downstream of the exit of the at least one nozzle when it is in its second inflated state.

9 A vertical take-off vehicle as claimed in any of the claims 1 to 8 wherein the at least one nozzle extends into the inner space of the at least one balloon when the at least one balloon is in its second inflated state.

10 A vertical take-off vehicle as claimed in any of claims 1 to 8 wherein the at feast one nozzle points towards the inner space of the at least one balloon when the at least one balloon is in its second inflated state.

11 A vertical take-off vehicle as claimed in any of the previous claims wherein the at least one balloon is tubular in shape.

12 A vertical take-off vehicle as claimed in claim 11 wherein the cross sectional area of the at least one balloon, when inflated, in a plane perpendicular to a longitudinal axis of the inflated at least one balloon is small at one end and which increases along the length of the at least one balloon in a direction away from that end to a wide part where the cross sectional area is relatively large and then decreases further along the length towards the other end.

13 A vertical take-off vehicle as claimed in either of claims 11 or 12 wherein the shape of the cross sectional area of the balloon is circular around the longitudinal axis of the at least one balloon.

14 A vertical take-off vehicle as claimed in any of claims 11 to 13 wherein one end of the at least one balloon is attached to the housing upstream of the exit of the at least one nozzle.

15 A vertical take-off vehicle as claimed in any of claims 11 to 14 wherein both ends of the at least one balloon are attached to the housing upstream of the exit of the nozzle when the at least one balloon is in its first folded state.

16 A vertical take-off vehicle as claimed in any of claims 11 to 15 wherein the housing comprises a main housing and an extended housing connected to the main housing via a frangible section;

wherein one end of the at least one balloon, when in its first folded state, is attached to the main housing and the other end is attached to the extended housing;

wherein, upon deployment of the at least one balloon, the frangible section is broken to enable the at least one balloon to expand from its first folded state to its second inflated state.

17 A vertical take-off vehicle as claimed in claim 16 wherein upon deployment of the at least one balloon, the frangible section is broken to allow the extended housing to move away from the main housing downstream of the exit of the nozzie to move one end of the at least one balloon connected to the extended housing away from the other end connected to the main housing to enable the at least one balloon to expand from its first folded state to its second inflated state.

18 A vertica! take-off vehicle as claimed in either of claims 16 or 17 wherein there is provided an explosive separator mounted on or adjacent to the frangible section wherein upon deployment of the at least one balloon, the explosive separator is detonated to break the frangible section.

19 A vertical take-off vehicle as claimed in any of claims 11 to 15 wherein the at least one nozzle comprises a first section connected to the combustion chamber and a second section connected to the first section via a frangible section;

wherein, in its first folded state, one end of the at least one balloon is attached to the main housing and the other end is attached to the second section;

20 A vertical take-off vehicle as claimed in any of claims 11 to 15 wherein the at least one nozzle comprises a first section connected to the combustion chamber and a second section connected to the first section via a frangible section;

wherein, in its first folded state, one end of the at least one balloon is attached to the first section and the other end is attached to the second section;

21 A vertical take-off vehicle as claimed in either of claims 19 or 20 wherein upon deployment of the at least one balloon, the frangible section is broken to allow the second section to move away from the main housing downstream of the first section of the at least one nozzle to move one end of the at least one balloon connected to the section from the other end to enable the at least one balloon to expand from its first folded state to its second inflated state.

22 A vertical take-off vehicle as claimed in any of claims 19 to 21 wherein there is provided an explosive separator mounted on or adjacent to the frangible section wherein upon deployment of the at least one balloon, the explosive separator is detonated to break the frangible section.

23 A vertical take-off vehicle as claimed in any of the previous claims wherein only one end of the at least one balloon, in its first folded state, is attached to the main housing;

wherein the at least one balloon is held in its first folded state via a retainer;

wherein, upon deployment of the at least one balloon, at least part of the retainer is broken to enable the at least one balloon to expand from its first folded state to its second inflated state.

24 A vertical take-off vehicle as claimed In claim 23 wherein there is provided an explosive separator mounted on or adjacent to the retainer wherein upon deployment of the at least one bailoon, the explosive separator is detonated to break the frangible section.

25 A vertical take-off vehicle as claimed in any of the previous claims wherein the at least one balloon when folded surrounds the longitudinal axis of the at least nozzle.

26 A vertical take-off vehicle as claimed in any of the previous claims wherein the at least one balloon when inflated surrounds the longitudinal axis if the at least one nozzle.

27 A vertical take-off vehicle as claimed in any of the previous claims wherein at least part of the at least one balloon, when in its first folded state, surrounds the at least part of the at least one nozzle.

28 A vertical take-off vehicle as claimed in any of the previous claims wherein at least part of the at least one balloon, when in its first folded state, forms a passageway through which the at least one nozzle extends.

29 A vertical take-off vehicle as claimed in any of the previous claims wherein the at least one balloon comprises pleats when in its first folded state.

30 A vertical take-off vehicle as claimed in any one of the previous claims wherein the at least one balloon is held in its first folded state by a retainer.

31 A vertical take-off vehicle as claimed in any one of the previous claims wherein there is further provided:

at least one tank mounted within the housing in which a liquid propellant can be stored; and at least one pump which pumps liquid propellant into the combustion chamber prior to it being burnt.

32 A vertical take-off vehicle as claimed in claim 31 wherein there is provided at least two tanks;

wherein the liquid propellant comprises a liquid fuel and a liquid oxidant;

wherein the liquid oxidant is held in one tank, the liquid fuel is held in the other tank.

33 A vertical take-off vehicle as claimed in either of claims 31 or 32 wherein there is provided a mixer which is capable of mixing the liquid propellant prior to it being pumped into the combustion chamber.

34 A vertical take-off vehicle as claimed in any of the previous claims wherein there is at least one storage container in which a solid propellant can be stored;

wherein the at least storage container also forms the at one least one combustion chamber in which the propellant can be burnt to generate exhaust gases.

35 A vertical take-off vehicle as claimed in any of the previous claims wherein the rate at which the at least one combustion chamber emits exhaust gases is controlled during the inflation and/or maintenance of the balloon.

36 A vertical take-off vehicle as claimed in any of the previous claims wherein apertures are formed through the wali of the balloon.

37 A multistage vertical take-off vehicle comprises at least two vertical take-off vehicles connected to each other either in series or in parallel or in a combination of series and parallel wherein at least one of the vertical take-off vehicles comprises a vertical take-off vehicle as claimed in claims 1 to 36.

38 A method of launching and returning a vertical take-off vehicle as claimed in any one of claims 1 to 36 wherein the method comprises the steps of:

i) providing the at feast one storage container with a propellant;

ii) burning the propellant in the at least one combustion chamber to generate exhaust gases;

iii) directing the exhaust gases through the at ieast one nozzle to propel the vertical take-off vehicle upwardly;

iv) deploying the at least one balloon after a predetermined period of time so that the at least one balloon expands from its first folded state to its second inflated state using the exhaust gases emitted from the at least one nozzle.

39 A method of launching and returning a vertical take-off vehicle as claimed in claim 38 wherein the method further comprises the step of maintaining the at least one balloon in its second inflated state using the exhaust gases emitted from the at least one nozzle.

40 A method of launching and returning a vertical take-off vehicle as claimed in any one of claims 1 to 36 wherein the method comprises the steps of:

i) providing the at least one storage container with a propellant;

iii) directing the exhaust gases through the at least one nozzle to propel the vertical take-off vehicle upwardly;

Iv) deploying the at least one balloon after a predetermined period of time;

v) maintaining the at least one balloon in its second inflated state using the exhaust gases emitted from the at least one nozzle.

41 A method of launching and returning a vertical take-off as claimed in any one of claims 38 to 40 wherein the method comprises the further step of ceasing to burn propellant in the at least one combustion chamber prior to the deployment of the at least one balloon, deploying the at least one balloon and then re-commencing burning the propellant.

42 A method of launching and returning a vertical take-off vehicle as claimed in any of claims 38 to 41 wherein the method comprises the step of varying the amount of propellant burnt in the at least one combustion chamber during the deployment of the at least one balloon and/or during the maintenance the at least one balloon in its second inflated state.