WO2021242474A2

WO2021242474A2 - Rocket launching and landing system

Info

Publication number: WO2021242474A2
Application number: PCT/US2021/030214
Authority: WO
Inventors: William Randall Mcdonnell
Original assignee: Advanced Product Development, Llc
Priority date: 2020-05-03
Filing date: 2021-04-30
Publication date: 2021-12-02
Also published as: WO2021242474A3

Abstract

A rocket launch and landing system hooks and latches the rocket (176) on a padded recovery line (171) sliding up the side of the rocket. The line is strung between two towers (173). This system can place the rocket back on the pad (177) for launch. The rocket body is used as a low-density decelerator by bringing the rocket down rotating slowly about a lateral axis and more perpendicular to the direction of travel. Multiple rebound maneuvers return the rocket to space to cool down before diving down to thick air to rapidly decelerate.

Description

ROCKET LAUNCHING AND LANDING SYSTEM

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of U.S. Provisional application 63/019,339, filed May 3, 2020, U.S. Provisional application 63/036,319, filed June 8, 2020, and U.S. Provisional application 63/042,693, filed June 23, 2020, the disclosures of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

[0002] This invention relates to rockets and to methods of launching and landing them.

SUMMARY OF THE INVENTION

[0003] This invention is designed to do one or more of the following:

[0004] A. Eliminate the need for the landing gear by hooking and latching on a padded recovery line sliding up the side of the rocket. The lines are strung between two towers. Why add all the weight, cost, complexity and potential failure modes of a landing gear and have to lift it up, accelerate it to high speed and then slow it down and lower it to the ground only to stabilize the rocket when on the ground? With this new approach the rocket can withstand winds and sea states that would cause a rocket with a landing gear to fall over or be blown over. It could also hold the rocket higher in the air, such as over 50 feet, for less saltwater corrosion. I have thrown a model rocket horizontally from approximately 20 feet away up against a slack line and the rocket hooks every time and remains engaged even without a latch. Try doing that with a rocket with a conventional landing gear. With this approach the rocket could also make a much harder landing with deceleration achieved over a longer distance with shock absorbing mechanisms provided by the slack recovery line and potentially shock absorbers connected to the recovery line.

[0005] B. Minimize fuel/oxidizer use especially for a second stage, or single stage to orbit, rocket by using the rocket body as a low-density decelerator by, for example, bringing the rocket down rotating about a lateral axis and more perpendicular to the direction of travel so fuel and oxidizer is only needed just prior to landing. By slowly rotating the fuselage about its long axis the maximum temperature and variation in temperature is minimized. This is an advantage over other low-density decelerators that I am aware of. Putting the rocket in this high drag configuration keeps the rocket coolest without using up rocket fuel/oxidizer because the rocket slows down the fastest and the stagnation temperature is a function of velocity.

[0006] C. Minimize heating with multiple rebound maneuvers to return to space to cool down before diving down to thick air to rapidly decelerate. Part of this invention is the rebound maneuver. The rocket uses the least fuel in a retro burn to bring it down skimming parallel to the top of the atmosphere where it immediately maneuvers down to thick enough air to then turn and maneuver back into space to cool down and for a sub-orbital flight to also extend the range. Previously, space planes entered the atmosphere producing lift which is the opposite of what you want to do because it keeps you longer in thin air at high speed for more heating. In accordance with this invention, once the rocket is going slow enough, it again pulls negative Gs to rapidly dive down to the landing site to slow down as fast as possible in the thick air.

[0007] D. Keep the crew compartment attached to the rocket to minimize refurbishment and because it makes it easier to use the rocket fuselage as a low-density decelerator. In one variant where the rocket is spinning about a lateral axis, the crew experiences g forces in the opposite direction of what they experience during launch so straps to restrain their head and feet would be desirable even though the g’s are not large. A virtual reality video in their helmet would make the astronauts appear to be hanging in the air facing down looking at the earth and experiencing gravity but with the spacecraft centerline describing a slow circular pattern around the vertical which accounts for the slow rotation of the rocket about its longitudinal axis to prevent hot spots. This video would be used to make sure passengers weren’t looking out the windows and sickened by the motion.

[0008] E. Allow a large center of gravity range using small control fins by rotating the rocket preferably about a lateral axis.

[0009] F. Allow a capability for the crew compartment to rapidly separate from the rocket. By rotating the rocket about a lateral axis, the crew compartment will be rapidly thrown clear of the rocket by centrifugal forces if the crew compartment is intentionally separated from the rocket or if the rocket explodes.

[0010] G. Allow greater thrust and efficiency by introducing an augmenter that entrains ambient air for greater thrust and also allows a high-altitude or vacuum rocket cone to operate at maximum efficiency at all altitudes. Also, the support structure for the rocket while on the launch pad as well as the augmenter are jettisoned early during the flight to avoid having to take that weight into orbit.

[0011] This disclosure focuses on the embodiment of a single-stage- to-orbit configuration, but this technology is also applicable to multi-stage rockets and missiles as outlined in my previous provisional patent applications that are incorporated herein by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG. 1 is a view looking along the axis of rotation of one of the control fins of the current invention showing a rotary actuator that can rapidly rotate the fin 360 degrees about its axis.

[0013] FIG. 2 is a side view of a single stage to orbit rocket.

[0014] FIG. 3 is the other side view of the rocket of FIG. 2.

[0015] FIG. 4 shows a mechanism that releases an augmenter from the rocket.

[0016] FIG. 5 shows the augmenter coming down under a parafoil and about to be snagged by a hook off the same recovery line used for the rocket. [0017] FIG. 6 shows the rocket maneuvering during a rebound maneuver.

[0018] FIG. 7 shows the rocket moving away from the viewer and rotating clockwise with the fuselage at near right angles to the direction of travel using its rocket body as a low-density decelerator for minimal heating without having to use up fuel.

[0019] FIG. 8 shows alternative orientation and fin positions of the rocket of FIG. 7 when using the fuselage as a low-density decelerator that moves the aerodynamic center away from the lower, rocket engine end of the rocket.

[0020] FIG. 9 shows the launch/recovery towers at the launch/recovery pad.

[0021] FIG. 10 shows five rocket nozzles looking up from below that take the place of one previous rocket nozzle to achieve better mixing of the rocket exhaust and ambient air.

[0022] FIG. 11 shows the interface between two streamlined fairings that go around the supports that hold the rocket up on the ground and transfer thrust from the augmenter to the rocket in flight. The streamlined fairings also provide control for the supports as they are rotating away from the rocket and control for the augmenter as it is dropping away from the rocket.

[0023] FIG. 12 shows a cross-sectional cut through a linear aerospike also benefiting from an augmenter around it.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

SINGLE STAGE TO ORBIT (SSTO)

AUGMENTER

[0024] A SSTO system of course wants to be as efficient as possible, more to keep the size of the vehicle down for a given payload than to reduce propellant. As such FIGS. 2 and 3 show the two side-views of a rocket 300 with an augmenter 301 around the rocket nozzles 302 that are arranged in a straight line at the base of the rocket. The augmenter benefits the rocket performance in six ways.

[0025] The rocket can use a high expansion ratio high-altitude or vacuum rocket nozzle at liftoff in the intense low pressure created in the augmenter which is more efficient.

[0026] The air sucked into the augmenter creates an intense low- pressure region that generates vertical thrust with this giant augmenter nozzle.

[0027] The augmenter allows a high-altitude/vacuum nozzle that works better for the rocket at high altitude also after the augmenter has dropped off. Most previous single-stage to orbit concepts have had to compromise between a low and high-altitude nozzle which doesn’t work as efficiently in either condition.

[0028] The augmenter reduces the rocket’s infra-red signature which is an advantage for military applications.

[0029] The augmenter reduces the noise which is important if the rocket is operated near populated areas for example for sub-orbital flights to locations on the other side of the world.

[0030] The augmenter draws in air behind the rocket body preventing or delaying flow separation which reduces the drag of the rocket body.

[0031] The augmenter 301 should allow approximately a 50% increase in thrust. Launch is the least efficient portion of flight because the rocket is moving so slowly so you want to take some of the benefit in increased acceleration rate but the faster you accelerate the more stress you put on the rocket and the lower the altitude you get to an airspeed where the augmenter loses thrust and it could be below the optimum altitude for the rocket nozzle so you probably want to take some benefit in fewer or smaller rocket engines. The augmenter is a converging/diverging nozzle. If the rocket engine exhaust was fuel rich in order to achieve burning in ambient air in the augmenter to avoid having to carry as much oxidizer, the bottom of the augmenter nozzle would preferably have a much longer diverging nozzle.

[0032] In the design shown in FIGS. 2 and 3 there are 8 supports 314 that support the rocket on the launch pad and carry the thrust from the augmenter 301 straight vertically up to the rocket body relative to the view in FIG. 3 and distribute the load pretty evenly around the circumference of the rocket and right in plane with the walls of the rocket for the lightest design. On the launch pad the load is carried from concrete ground supports 339 directly to the base of supports 314 and there are six of these concrete ground supports under each of the bottom ends of the supports 314 that form an “M” as seen in FIG. 2. These supports 314 on the rocket are drawn as round in cross-section for clarity but would be streamlined for two reasons. One reason is to reduce drag during the ascent of the rocket and the other reason is to control the rotation of these supports 314 away from the rocket just prior to jettisoning the augmenter and they can also be used to control the augmenter as it leaves the rocket like tail fins.

[0033] At the two upper points and the one lower middle point of the “M” the supports come together. Lightweight streamlining fairing 340 over these supports come together at these three spots as shown in FIG. 11 and are connected by gears so that one actuator (not shown for simplicity) can control the orientation of all the streamlined fairings 340 over the supports 314 in the “M” even though there may be more than one actuator for redundancy.

[0034] After the augmenter is no longer supporting its own weight and drag, at let’s say over 60,000 feet, the orientation of the streamlined fairings 340 can be used to hold the supports against the rocket since the augmenter may still be benefiting the rocket nozzle more than it is hurting the ascent from its drag and weight. However, when it is desirable to jettison the augmenter as shown in FIG. 3 the streamlined fairings 340 are rotated to a position that causes aerodynamic forces 336 to start rotating the supports 314 away from the rocket body. Aerodynamic forces 337 from these streamlined fairings keep the supports from rotating down too fast and forces 338 also slow the rotation before the supports 314 end up facing aft and outward. The supports 314 can rotate quite far downward because there is a cavity where the concrete ground support 339 extended into the augmenter, that the base of the support 314 can now rotate into. An air bag or shock absorber could also be used in case there is a malfunction of this aerodynamic system so the supports 314 or augmenter 301 don’t get damaged.

[0035] There are also three pairs of supports 303 in this particular design that are streamlined because they are close to perpendicular to the airflow being drawn into the augmenter. They are also preferably close laterally to the base of the supports 314. These supports 303 stabilize the augmenter and assist in countering the strong vacuum forces trying to push the walls of the augmenter together. The middle pair of supports 303 as viewed from FIG. 2 are the only thing preventing the augmenter from dropping from the rocket. FIG. 4 shows how the augmenter 301 is released from these middle supports 303 and thus released from the rocket as well. Rotary actuator 400 through worm gear 401 turns rod 402 and 403, which are inside supports 303, which rotates hooks 404 and 405 out of engagement with steel rings 406 and 407 respectively thus releasing the augmenter 301 .

[0036] You generally want to leave the augmenter 301 on until after it is no longer even supporting its own weight and drag because it generally will still be helping the rocket nozzles’ thrust and efficiency. At some point of course you want to jettison it. This is done by pointing the outer-most rocket nozzles 304 and 305 outboard which increases the force pushing the augmenter away from the rocket and also holds it along the vehicle centerline so it doesn’t contact the rocket nozzles. The aerodynamic fairings 340 are now behind the augmenter and they also can be used to control the augmenter as tail fins as it leaves the rocket and can also be used to increase drag by rotating to an un-streamlined position. To release the augmenter, the two rods/supports 306 shown in FIG. 4, which are connected through a universal joint 307 are rotated by the actuator 308 shown which rotates hooks 309 and 310 out of the way of the rings 311 and 312 so the augmenter is quickly blown backward away from the rocket. These hooks 309 and 310 are located at 313 on the top of the augmenter 301 at the interface between the supports 314 and the augmenter 301 at the centerline of the rocket as shown in FIG. 2.

[0037] After the augmenter 301 drops off the rocket, a steerable parafoil 315 is deployed as shown in FIG. 5 and the augmenter flies back and the parafoil is snagged by a hook 316 in the same approach used for years by helicopters but now on the same line 171 that is used to recover the rocket. By reeling in and out the winches 172 as shown in FIG. 9 for the two towers, the augmenter 301 is automatically moved and deposited in an upright position on the launch and recovery pad 320 for the next launch. The parasail 315 carries the augmenter 301 upright even though it is more drag in order to be in the right attitude to place back on the launch pad. The augmenter 301 is carried lengthwise to be the lowest drag in an upright position. If there is a malfunction in the system that controls the winches 172 and automatically maneuvers the hook 316 to snag the parasail 315, then as backup there would be a “ground level trampoline” past the recovery line 171 for the augmenter 301 to land on but with primarily dampers instead of springs so the augmenter doesn’t bounce. The dampers would have enough spring force in them to return the “trampoline” surface back to the level position after removing the augmenter. After landing on the “trampoline,” or in order to drop the augmenter onto the “trampoline” before it might overshoot the “trampoline,” the left or right side parafoil lines might be released from the augmenter at 321 and 322.

REBOUND MANEUVER

[0038] The rebound maneuver uses the least amount of propellant in a retro burn to put the rocket skimming along the top of the atmosphere where it immediately maneuvers down toward the earth as shown in FIG. 6 to rapidly get to thick enough air to then roll 180 degrees, so passengers always feel g’s in the more comfortable upward direction, and powerfully maneuver back into space, then repeat the maneuver with steeper parabolic trajectories. The rocket is shown flying backwards with relative wind 326 because the base is already designed to withstand heat. Lift 327 and 328 on control fins 324/325 and wings 323 respectively along with lift and drag 329 on the rocket body are the major forces causing the rocket to maneuver. By designing the rocket statically stable flying in this direction the rocket will quickly right itself into a vertical attitude after it stops rotating about a lateral axis just before landing. If the rocket ends up with a center- of-gravity so far back that the control fins 324/325 even with artificial stabilization can’t stabilize the rocket, the rocket can roll 90 degrees so the wings 323 that the rocket engines are mounted on don’t act to destabilize the rocket in pitch. It will of course be less maneuverable in this configuration. The rocket could be designed to always rebound in this orientation with the wings 323 oriented vertically in order to allow smaller control fins.

[0039] The rocket could initially be aimed at a point to the left or right of the landing zone and if the rocket starts going short it points more directly at the landing site. If it is going long it could turn a little away from the landing site and make a more circular path toward the landing. RE-ENTRY

[0040] Just before arriving over the landing site the rocket could start rotating about its lateral axis using its thrusters before it re-enters the atmosphere for the last time but generally would either use aerodynamic forces like a conventional aircraft entering into a spin or preferably would enter the atmosphere with the fuselage at right angles to the direction of travel as shown in FIG. 7 where the vehicle is traveling away from you with the control fins 324 and 325 generating aerodynamic forces 330 and 331 to start rotating the vehicle about a lateral axis 332. Rotating about a lateral axis allows the rocket to keep its body closer to right angles to the direction of travel with a very wide range of centers of gravity and small control fins 324/325. The faster the rocket rotates about this lateral axis the closer the rocket body will get to being perpendicular to the direction of travel. In this way it can control its drag and thus how far down range the vehicle travels. The rocket actually doesn’t want its center of gravity right at its aerodynamic center because the rocket will naturally orient itself with its axis of rotation close to parallel to the direction of travel. The rocket can change its aerodynamic center to make sure it isn’t exactly where the center of gravity is by either having the control fins 324/325 parallel to the direction of travel such as shown in FIG. 7 or perpendicular to the direction of travel like control fins 333 and 334 shown in FIG. 8.

[0041] The fins 324/325/333/334 are swept forward for less drag traveling up to space and also in rebound maneuvers but also because it increases the moment arm to the rocket center of gravity 332 to be more effective in controlling and generating the rotation about this lateral axis. It will be understood of course that the control fins 324/325/333/334 could be substantially smaller if you didn’t want to do the rebound maneuver in the manner shown in FIG. 6. Instead you could do the rebound maneuver while rotating about the lateral axis as will be discussed shortly tilting the plane of rotation to first maneuver down and then maneuver back up into space but you wouldn’t be able to travel as far down range using this approach which is beneficial for sub-orbital flights.

[0042] The rocket controls its plane of rotation relative to its flight path, and thus the direction it translates relative to its flight path, in the same way that a rotor plane is tilted on a helicopter and controls where a helicopter goes. If the rocket is always in the configuration shown in FIGS. 7 and 8 when rotating around, the plane of rotation will tilt to the right and the vehicle will translate to the right relative to its movement directly away from the viewer for the same reason it works for a helicopter rotor. In both FIGS. 7 and 8 there is more drag on the rocket at the bottom of the figure and it is this asymmetry that causes the plane of rotation to tilt and the rocket to maneuver toward the right of the figure. If either configuration of FIGS. 7 or 8 are maintained for a full rotation then the rocket won’t be biased to maneuver in any direction. The total drag of the rocket can be increased/decreased by increasing/decreasing the rate of rotation about the lateral axis since this rotation drives the rocket body toward a position perpendicular to the direction of travel. Placing the fins in a position to create drag and also push the downstream end of the rocket away from the center of rotation can also help increase the drag.

[0043] The rocket can also be slowly rotated about its longitudinal axis to achieve even expansion and contraction from heating and to avoid hot spots which is something not found on other low-density decelerators that I am aware of. Roll is powered by having a control fin 324/325/333/334 on one side of the rocket more streamlined to the flow than the fin on the other side of the rocket. One advantage of not rotating the rocket about its longitudinal axis is that one side of the rocket will stay cooler and needs less insulation or high temperature materials.

[0044] As the rocket rotates about a lateral axis, the crew experiences g-forces in the opposite direction of what they experience during launch so straps to restrain their head and feet would be desirable though the g’s don’t have to be large at all. A virtual reality video in their helmet would make the astronauts appear to be hanging in the air facing down looking at the earth and experiencing gravity but with the spacecraft centerline prescribing a slow circular pattern around the vertical because of the slow rotation of the rocket about its longitudinal axis to avoid hot spots. This video would be used to make sure the passengers weren’t looking out the windows and sickened by the motion.

NO LANDING GEAR

[0045] The rocket lands by engaging a slack line held up by an elevated structure. The line is slack to prevent any loads on the side of the rocket before engaging the hook. For rapid re-usability this hook and recovery line approach can be used to erect the rocket before launch, transfer passengers to the crew compartment and provide a portion of the lightning protection. For lightning protection there would be two other towers (not shown) and a ring around the main recovery line would be pulled over by a line from one of the other towers (not shown) so the recovery line forms two of the four sides of the lightning protection. The other two sides would always be up and could also be used for landing of other SSTOs or as backup.

[0046] FIG. 9 shows a passenger carrying rocket 176 like the SpaceX BFR after it has just landed near a major city. The rocket engaged the padded recovery line 171 with two hooks 170. The passengers have gone from being on their backs for landing to upright in a matter of seconds. Winches 172 at the base of each tower 173 moved the rocket sideways away from the landing pad 177 that the rocket 176 just landed over in order not to send up sea water spray to limit corrosion. The rocket 176 is moved over to place on catamaran 174 by having one of the winches 172 reel in and the other reel out in order to line it up with the padded cradle 175 on catamaran 174. Once on the padded cradle 175 the latches on hooks 170 are retracted and the catamaran moves forward pulling the recovery line out of the hooks 170. As passengers are traveling back to the terminal they can climb out of the rocket and get in a pod (not shown) on one of the catamaran floats to get off at the terminal or alternatively the equivalent of a jetway can come out to the rocket. If landing pad 177 is also used for launching then catamaran 174 would back up the rocket until it once again engaged hooks 170 with line 171 but with the rocket facing in the other direction so the catamaran doesn’t have to turn around. A line would be attached to the bottom of the first stage of the rocket 176 and after the winches 172 lifted and transported the first stage over to the launch pad the line attached to the bottom of the rocket would be connected to winch 178 to pull the first stage into a vertical position and pull the base of the rocket where it needs to go on the launch pad. The towers 173 would of course be taller than shown so they could also lift the second stage and passenger compartment onto the first stage. For the second stage the line from the winch 178 goes through a pulley 182 before connected to the bottom of the second stage. The structure 183 that the pulley 182 is mounted on would rotate about hinges 184 to place the pulley approximately at the height of the first stage so winch 178 could pull the second stage into the vertical position and onto the first stage. It will be understood that instead of a catamaran the conveyance for the rocket could have been a wheeled vehicle. Before launching the rocket, a line 179 is retracted by winch 181 which pulls ring 180 around recovery line 171. At the same time winch 172 extends so recovery line 171 ends up moving out of the way of the launch of the rocket and now provides part of the lightning protection for the rocket. Just prior to that, line 171 lifted a passenger compartment with similar hooks to the rockets over the compartments center of gravity off the same catamaran or one similar and raised the passenger compartment up to the side of the passenger compartment for loading. Also two lines from winch 178 extending up through the pulley at the top of structure 183 were attached to the lines just above the winches 172 and were run up these lines to the point 180 and its equivalent on the other tower by alternately reeling in one pulley and reeling out the other to form the other side of the lightning protection for the rocket.

[0047] After landing within seconds of engine shutdown the passengers go from being on their backs to upright since the hooks can be located laterally from the rocket center of gravity. The winches 172 can immediately and automatically move the rocket laterally from over the landing pad 177 and lower it onto a water or ground vehicle 174 for transfer back to its hangar by reeling in and out the line from the two towers as shown in FIG. 9 or the rocket could be immediately placed back on the launch pad supports for launch. [0048] Although conventional rocket nozzles were shown in this example a linear aerospike nozzle might have greater potential for mixing of the rocket exhaust and ambient air for greater thrust, lower infrared signature and lower noise. FIG. 12 shows a cross-sectional cut through an aerospike nozzle 503 and its augmenter 504 around it. Again it is better at least for mixing of the rocket exhaust and ambient air if the aerospike is not a cone but wider in one direction than another similar to the six rocket cones lined up in a row shown in FIGS. 2 and 7 versus only one rocket cone when viewed from the other side as shown in FIGS. 3 and 8. This is because again there is more potential for mixing of the rocket exhaust and ambient air.

[0049] A lower cost and risk approach is shown in FIG. 10 where one gimbaling rocket nozzle is replaced by five rocket nozzles 500 that gimbal together as a unit and have a streamlined way for ambient air to flow in between the nozzles which is shown as three parallel lines between the nozzles. The middle line is the sharp trailing edge of the airfoil structure 501 supporting each of the outer four nozzles 500 and the other two lines are the maximum thickness of the airfoils. FIG. 10 is a view looking up into these five rocket nozzles. This provides more area of mixing between rocket exhaust and ambient air for more of the six benefits described earlier.

[0050] Although this disclosure shows a configuration where the supports 314 drop off of the rocket with the augmenter, these supports could also remain connected to the rocket body at their top end and the outboard ends of the supports 303 at their bottom end. This is a simpler approach but it means that their weight and drag would have to be raised and accelerated up to orbital speeds and then back down and would have to take the heat of re-entry and cause additional drag during rebound maneuvers. The augmenters are of course not necessary for the other features disclosed herein. ALTERNATE EMBODIMENTS

[0051] Although the preferred way to use the rocket body as a low- density decelerator is to rotate it about a lateral axis it is also possible to rapidly rotate it about a longitudinal axis. This is not as desirable since the moment of inertia is smaller so it must rotate more rapidly. My provisional patent applications go into more detail on this approach but anyone skilled in the art can figure out how control fins 333, 334, 324, 325 can control a rocket spinning about its longitudinal instead of lateral axis similar to that explained for the preferred approach of rotating about a lateral axis. Briefly, an electric motor/actuator 112 to do this is shown in FIG. 1 where through gear 113 it rotates gear 114 which is attached to a fin 102.

[0052] Another way to use the rocket fuselage as a low-density decelerator is to drive the longitudinal axis to more than 30 degrees misalignment with the direction of travel using aerodynamic surfaces that force the lighter end of the rocket, which is usually the downwind side of the rocket, back and force at a frequency within plus or minus 80% of the natural frequency of oscillation. For all of the embodiments in this disclosure driving the longitudinal axis of the rocket to 40 degrees misalignment is better than 30, 50 better than 40, 60 better than 50, 70 better than 60, 80 better than 70, 90 better than 80. Also for this particular approach of oscillating back and forth, 100 degrees is better than 90 and 110 better than 100. It is better to drive the rocket more than perpendicular to the direction of travel during this oscillation because then the rocket spends more time near 90 degrees where the drag is the maximum. If you want only one side of the rocket to have more heat insulation or protection than the other side then the rocket could rotate 180 degrees about its longitudinal axis when that axis is parallel to the direction of travel. This however would require larger fins than are otherwise necessary. In FIG. 8 if the rocket is moving up relative to the figure then fins 324 and 325 or 333 and 334 could drive their end of the rocket back and forth to increase the drag. Box fins like used on SpaceX rockets could of course also be used. The rocket can maneuver while oscillating back and forth this way by driving the lightweight side of the rocket more in one direction than the other or by temporarily stopping the oscillation and holding the rocket body at an angle of attack.

[0053] In the unlikely case that the rocket’s center of gravity is very close to the aerodynamic center when the rocket body is oriented perpendicular to the direction of travel then variable drag devices like fins 333, 334, 324, 325 on the front and/or back of the rocket can keep the rocket’s longitudinal axis close to perpendicular to the direction of travel without rotating about any axis. For example, by streamlining the fins 324 and 325 such as shown in FIG. 7, the rocket can tilt the top end down toward the direction of travel and by putting fins 333 and 334 into a high drag position such as shown in FIG. 8, the rocket can tilt the bottom end of the rocket down toward the direction of travel. With all of these alternate embodiments, a virtual reality headset could play a video that makes passengers think they are hanging above the earth instead of going through movements that might make them nauseous.

[0054] Also a drag device like a parachute on a harness with similar- length lines extending to points on either side of the rocket’s center of gravity in the longitudinal direction could hold the rocket’s longitudinal axis close to perpendicular to the direction of travel as shown in my provisional patent application. Trying to deploy a parachute that can survive this high speed, high-temperature, environment however would be difficult.

[0055] I consider my invention to include any of the claims in combination with any other claims. My invention also includes those variations in the disclosed apparatus, systems, and methods which are apparent to those skilled in the art in light of the present disclosure.

[0056] am also claiming as my invention all the claims in my previous provisional applications directed to this invention, namely U.S. Provisional application 63/019339, filed May 3, 2020, U.S. Provisional application 63/036319, filed June 8, 2020, and U.S. Provisional application 63/042693, filed June 23, 2020, the disclosures of which are hereby incorporated by reference.

Claims

CLAIMS I claim:

1 . A rocket equipped to land vertically using rocket power that can use its body as a low-density decelerator with its longitudinal axis more than 20 degrees misaligned with the direction of travel by rotating the rocket about a lateral axis.

2. The rocket of claim 1 where the longitudinal axis is driven to more than 20 degrees misaligned with the direction of travel using aerodynamic surfaces to oscillate the longitudinal axis of the rocket back and force at a frequency within plus or minus 80% of the natural frequency of oscillation.

3. The rocket of claim 2 wherein the aerodynamic surfaces are box fins.

4. The rocket of any of claims 1 to 3 wherein the longitudinal axis is driven to more than 40 degrees of misalignment with the direction of travel.

5. The rocket of claim 4 wherein the longitudinal axis is driven to more than 60 degrees of misalignment with the direction of travel.

6. The rocket of claim 5 wherein the longitudinal axis is driven to more than 70 degrees of misalignment with the direction of travel.

7. The rocket of claim 6 wherein the longitudinal axis is driven to more than 80 degrees of misalignment with the direction of travel.

8. A rocket and a launch/recovery tower, said rocket being free of a landing gear but having a capture device #1 capable of engaging a capture device #2 on said launch/recovery tower during landing of said rocket while said rocket is supported by rocket thrust, and said launch/recovery tower and capture device #2 is capable of moving said rocket to a launch position.

9. The rocket and tower of claim 8 wherein a line is used to pull the bottom of the rocket into proper alignment on the launch pad.

10. The rocket and tower of claim 9 wherein a winch is used to pull the line to pull the bottom of the rocket into proper alignment on the launch pad.

11 . The rocket and tower of claim 8 where a second stage rocket can engage said capture device #2 and be moved onto the top of a first stage rocket on a launch pad.

12. The rocket and tower of claim 11 wherein a winch is used to pull the bottom of the second stage rocket onto the top of the first stage rocket.

13. A rocket and a launch/recovery tower, said rocket being free of a landing gear but having a first capture device capable of engaging a second capture device on said launch/recovery tower during landing of said rocket while said rocket is supported by rocket thrust, and said launch/recovery and capture second device is capable of moving said rocket to a vehicle for transportation of said rocket back to a hangar.

14. The rocket and launch/recovery tower of claim 13 wherein said vehicle is a ground vehicle.

15. A rocket that during re-entry to the atmosphere initially maneuvers down toward the earth to more quickly engage thicker air and then reverses direction to maneuver back into space to cool down before again re-entering the atmosphere..

16. The rocket of claim 15 wherein a minimal retro-burn is used to bring the rocket down to skim on the top layers of the atmosphere prior to maneuvering down toward the earth.

17. The rocket of claim 15 wherein the rocket travels backwards relative to the direction it travels during launch.