United States Patent [19]
`Lane et al.
`
`US005873549A
`[11] Patent Number:
`[45] Date of Patent:
`
`5,873,549
`Feb. 23, 1999
`
`[54] VEHICLE ROTATION AND CONTROL
`MECHANISM
`
`[75] Inventors: Je?'ery G. Lane, Irvine; James R.
`French, Los Angeles, both of Calif.
`
`[73] Assignee: McDonnell Douglas Corporation,
`Huntington Beach, Calif.
`
`[21] Appl. No.: 719,457
`[22]
`Filed:
`Sep. 25, 1996
`
`[51] Int. Cl.6 .......................... .. F42B 10/14; F42B 10/50;
`F42B 15/01; B64G 1/62
`[52] US. Cl. ................... .. 244/160; 244/138 A; 244/139;
`244/63; 244/3.28; 102/384; 102/388
`[58] Field of Search ................................ .. 244/3.28, 3.29,
`244/138 A, 138 R, 139, 160, 164, 63; 102/384,
`385, 388
`
`[56]
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`1,324,433 12/1919 Phillips, Jr. ........................... .. 102/384
`2,840,328
`6/1958 Richardson et a1.
`244/113
`3,065,937 11/1962 Vigil.
`3,098,445
`7/1963 Jackson ............................. .. 244/138A
`3,118,636
`1/1964 Kantrowitz et al. .
`3,181,824
`5/1965 Anania .................................. .. 244/160
`3,210,025 10/1965 Lubben et al. .
`3,246,864
`4/1966 Mack et a1. ....................... .. 244/138 A
`3,776,490 12/1973 Weis ..................................... .. 244/3.27
`3,903,801
`9/1975 Senoski.
`
`4,007,505
`4,832,288
`4,896,847
`5,031,857
`5,322,248
`5,398,888
`
`2/1977 Nowatzki ............................. .. 244/3.28
`5/1989 Kendall et a1. .
`1/1990 Gertsch.
`7/1991 Macconochie et a1. ............. .. 244/3.28
`6/1994 Ragab.
`3/1995 Gerhardt .............................. .. 244/3.27
`
`Primary Examiner—V. Lissi Mojica
`Attorney, Agent, or Firm—Harness Dickey & Pierce P.L.C.
`
`[57]
`
`ABSTRACT
`
`Anose assembly and method for controlling the rotation and
`stabilizing the orientation of a vehicle during landing
`maneuvers. The vehicle includes a nose assembly that is
`coupled to an airframe thereof and that has a frame and ?ap
`assembly. The ?ap assembly includes an actuating means
`and a ?ap coupled to the frame such that the actuating means
`moves the ?ap from and betWeen a fully retracted position
`and a fully extended position in response to a guidance
`signal received from a ?ight control computer. In a preferred
`embodiment of the present invention, the ?ap assembly
`includes a plurality of ?aps each coupled to the nose
`assembly frame and an actuating means that selectively
`positions the plurality of ?aps in response to a signal. The
`method for rotating a vehicle from a nose-forward orienta
`tion to a base-forward orientation includes the steps of
`orientating the vehicle in nose-forward ?ight, rotating the
`vehicle in a ?rst direction, and selectively actuating one of
`a ?rst and second ?ap from a retracted position toWard an
`extended position to generate a damping moment tending to
`position the vehicle in a base-forward orientation.
`
`20 Claims, 3 Drawing Sheets
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`

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`U.S. Patent
`
`Feb. 23, 1999
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`Sheet 1 of 3
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`5,873,549
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`I
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`\1
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`;
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`Space Exploration Technologies; NEW PETITION
`Exhibit 1004
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`Page 2 of 8
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`‘»~\,.“‘”-L-"§%
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`

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`U.S. Patent
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`Feb. 23, 1999
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`Sheet 2 of3
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`5,873,549
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`380
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`

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`U.S. Patent
`
`Feb. 23, 1999
`
`Sheet 3 of3
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`5,873,549
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`/////////
`
`

`
`1
`VEHICLE ROTATION AND CONTROL
`MECHANISM
`
`BACKGROUND OF THE INVENTION
`1. Technical Field
`The present invention relates generally to a direction
`control assembly for an aerospace vehicle and, more
`particularly, to a ?ap assembly at the forebody of a reusable
`launch vehicle for rotating and stabilizing the vehicle during
`entry and pre-landing maneuvers.
`2. Discussion
`Reusable launch vehicles used to deploy satellites in a
`predetermined orbit about the earth include single stage to
`orbit (“SSTO”) vehicles that are designed to perform their
`intended operation and return to earth Without jettisoning
`any portions of the vehicle. Accordingly, SSTO vehicles do
`not include discardable booster rockets or fuel tanks. Rather,
`the fuel supply elements of SSTO vehicles are retained
`throughout the ?ight thereby increasing the need to mini
`miZe fuel consumption in order to decrease the unusable
`Weight carried into orbit. The present invention addresses
`these concerns by providing a vehicle rotation and control
`mechanism that reduces propellant acquisition subsystems
`and the propellant required to properly position the vehicle
`for landing.
`Vertically landing SSTO vehicles commonly include a
`conically shaped airframe con?gured for stable ?ight in a
`nose-forWard orientation. HoWever, since the vehicle is
`vertically landed in a rearWard or tail-?rst orientation a
`rotation of the vehicle during the landing sequence is
`required. Currently, SSTO vehicles of this class perform the
`rotation maneuver through the use of engine poWer. More
`speci?cally, the maneuver includes starting several of the
`main engines, retracting entry ?aps so that the vehicle
`pitches up to initiate rotation, and selectively throttling up
`the engines to arrest rotation and place the vehicle into the
`desired base-?rst orientation. In order to minimiZe the
`quantity of propellant consumed by the engines betWeen the
`rotation and touch doWn phases of the landing procedure,
`this rotation maneuver is generally conducted at a relatively
`loW altitude. While this procedure is viable, a considerable
`amount of propellant is used during the starting and opera
`tion of the engines and the propellant feed system becomes
`heavy and complex. Further, the relatively loW altitude
`compresses landing functions into a shorter timeline.
`
`SUMMARY OF THE INVENTION
`The present invention provides a nose assembly and
`method for controlling the rotation and stabiliZing the ori
`entation of an aerospace vehicle during landing maneuvers.
`The vehicle includes a nose assembly that is coupled to an
`airframe and that has a frame and ?ap assembly. The ?ap
`assembly includes an actuating means and a ?ap coupled to
`the frame such that the actuating means moves the ?ap from
`and betWeen a fully retracted position and a fully extended
`position in response to a guidance signal received from the
`?ight control computer. In a preferred embodiment of the
`present invention, the ?ap assembly includes four of ?aps
`each coupled to the nose assembly frame and an actuating
`means that selectively positions each ?ap in response to a
`signal. A method for rotating the vehicle from a nose
`forWard orientation to a base-forWard orientation according
`to the present invention includes the steps of orientating the
`vehicle in nose-forWard ?ight, rotating the vehicle in a ?rst
`direction, and selectively actuating one of a ?rst and second
`?ap to an extended position to generate a damping moment
`tending to position the vehicle in a base-forWard orientation.
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`BRIEF DESCRIPTION OF THE DRAWINGS
`
`Other objects and advantages of the invention Will
`become apparent upon reading the folloWing detailed
`description and upon reference to the draWings, in Which:
`FIG. 1 is a perspective vieW of a reusable launch vehicle
`in accordance With the present invention;
`FIG. 2 is a front partial sectional vieW of the nose cone of
`the vehicle shoWn in FIG. 1 With a ?ap removed for clarity;
`FIG. 3 is an exploded perspective vieW of the nose cone
`shoWn in FIG. 2; and
`FIG. 4 is a schematic illustrating the orientation and nose
`?ap position during the landing rotation sequence of the
`single stage to orbit vehicle shoWn in FIG. 1.
`
`DETAILED DESCRIPTION
`The folloWing description of the preferred embodiment of
`the present invention is merely exemplary in nature and is in
`not intended to limit the scope of the claimed invention.
`Moreover, While depicting the invention in a single stage to
`orbit (“SSTO”) vehicle, the description is intended to
`adequately teach one skilled in the art to make and use the
`vehicle rotation and control mechanism and method
`described and claimed herein in a variety of aerospace
`vehicles.
`As illustrated in FIG. 1 of the draWings, a vertically
`landing reusable launch vehicle 10 includes a generally
`conical shaped airframe 12 de?ning a forebody 14 and a
`thrust structure 16. Thrust structure 16 includes a base 18
`proximate to Which landing gear 20, ?ns 22, and rear ?aps
`24 are coupled to airframe 12. The forWard portion of rear
`?aps 24 are pivotably connected to airframe 12 in a manner
`knoWn in the art and an actuating mechanism (not shoWn)
`communicates With a ?ight control computer (not shoWn)
`and is coupled to rear ?aps 24 to control the angular position
`thereof relative to airframe 12. During normal, nose-?rst
`?ight, the ?ight computer selectively positions rear ?aps 24
`to stabiliZe the ?ight path and orientation of vehicle 10.
`Forebody 14 of airframe 12 includes a nose cone 26 that
`is shoWn in FIGS. 2 and 3 to include a ?ap assembly 30
`having a ?ap actuating apparatus 32 connected to an upper
`bulkhead ring 28. Nose cone 26 further includes a loWer
`bulkhead ring 34, a plurality of ?aps 38a, 38b, 38c, and 38d
`pivotably connected to loWer ring 34 via hinge assemblies
`40, a cap 42 (FIG. 1) securable to upper ring 28 in a manner
`knoWn in the art, and stringers 44 having a ?rst end 46
`connected to upper bulkhead 28 and a second end 47
`con?gured to cooperate With loWer bulkhead 34. Assembly
`30 preferably includes four (4) circumferentially opposed
`and separately operable ?aps that form ?ap pairs capable of
`providing opposing damping moments during vehicle ?ight.
`As best seen in FIG. 2, ?aps 38a and 38b illustrate one of the
`pair of opposed ?aps Wherein ?ap 38a is shoWn in a fully
`extended or fully pivoted position Whereas ?ap 38b is fully
`retracted. In a manner knoWn in the art, actuating apparatus
`32 selectively positions ?aps 38a and 38b at or betWeen the
`fully extended and fully retracted positions in response to an
`input signal received from the vehicle’s ?ight computer (not
`shoWn).
`When constructed as described herein and as best seen in
`FIG. 2, cap 42, upper ring 28, an outer surface 48 of ?aps 38,
`and a radially outer surface 50 of stringers 44 cooperate to
`de?ne a relatively smooth and aerodynamic outer surface
`surrounding a cavity 52. In the preferred embodiment, cavity
`52 houses an auxiliary liquid oxygen tank 54 and actuating
`apparatus 32. More particularly, a conical support 56 is
`
`

`
`3
`shown to include a lower ?ange 58 fastened to loWer
`bulkhead ring 34 and an upper ?ange 59 connected to
`support auxiliary tank 54. Tabs 63 are connected to conical
`support 56 to provide additional support for tank 54.
`HoWever, those skilled in the art Will appreciate that a
`variety of alternative locations are available Within vehicle
`10 for both tank 54 and actuating apparatus 32. As is
`common in the art, each of the structural members of nose
`cone 26, ie upper bulkhead ring 28, loWer bulkhead ring 34,
`cap 42, stringers 44, and conical support 56, are composed
`of a high strength and loW Weight composite such as a
`graphite epoxy. LikeWise, those skilled in the art Will appre
`ciate that the portions of each member eXposed to the
`atmosphere during reentry is provided With a heat resistant
`material such as alumina enhanced thermal barrier (AETB)
`tiles.
`With reference to FIGS. 2 and 3, actuating apparatus 32
`of ?ap assembly 30 preferably includes an actuator housing
`60 coupled to nose cone 26 such as by a plurality of radially
`extending mounting arms 62 interconnecting actuator hous
`ing 60 and upper ring 28. Actuator housing 60 is coupled for
`communication With the ?ight control computer in a manner
`knoWn in the art and is operationally connected to ?aps 38a,
`38b, 38c, and 38d via telescoping arms 64 having a ?rst end
`66 coupled to actuator housing 60 and a distal end 68
`coupled to ?ap 38. Actuating apparatus 32 may include a
`variety of hydraulic or electromechanical actuators knoWn in
`the art such as, for eXample, hydraulic actuator part number
`ARG 7376-5007 manufactured by BF. Goodrich of
`Cleveland, Ohio or the hydraulic or electromechanical
`actuators commercially available from Allied-Signal of
`Torrance, Calif. HoWever, various equivalent actuating
`assemblies are readily available and adaptable for use With
`the present invention.
`Launch vehicle 10 normally operates in a nose-forWard
`orientation. HoWever, in preparation for landing, it is nec
`essary to reorient vehicle 10 into a rearWard or base-?rst
`orientation such that landing gear 20 is positioned to contact
`the landing surface. The present invention performs the
`rotation and descent sequence With limited propellant con
`sumption and at a relatively high altitude in comparison to
`current SSTO vehicle systems of this type. Speci?cally, ?ap
`assembly 30 of the present invention alloWs the ?ight
`control system to selectively position the ?aps 38a, 38b, 38c,
`and 38a' to stabiliZe reusable launch vehicle 10 during
`rearWard ?ight as Well as to modulate the ?ap positions to
`perform the rotation maneuver required to land vehicle 10.
`Selective actuation of ?aps 38 by actuating apparatus 32
`provides for the rotation of vehicle 10 according to a speci?c
`sequence such as landing sequence 70 shoWn in FIG. 4 and
`described herein. Prior to initiation of landing sequence 70,
`rear ?aps 24 are in a partially or fully eXtended position in
`order to stabiliZe the ?ight path and orientation of reusable
`launch vehicle 10 as shoWn at reentry stage 72. In order to
`minimiZe propellant consumption, vehicle engines 19 are
`maintained in an off state during the initiation of landing
`sequence 70 alloWing vehicle 10 to travel along a generally
`parabolic ?ight path 78. While the initial stabiliZation of
`vehicle 10 is described at reentry stage 72 as being provided
`by rear ?aps 24, those skilled in the art Will appreciate that
`other stabiliZation techniques and structures may be used
`Without departing from the proper scope of the appended
`claims.
`Landing sequence 70 is initiated by retracting rear ?aps
`24 thereby initiating pitch up of vehicle 10 as shoWn at pitch
`up stage 74. The ?ight control computer of vehicle 10 is
`programmed to de?ect leeWard nose ?ap 38a at an angle
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`suf?cient to provide a predetermined damping moment that
`sloWs the clockWise rotation of vehicle 1 0 indicated by
`arroW 76.
`In the preferred rotation sequence illustrated in FIG. 4, the
`rotation occurring at pitch up stage 74 causes clockWise
`rotation of vehicle 10 beyond the rearWard ?ight orientation
`before the damping effects of eXtended ?ap 38a eliminates
`rotation. Accordingly, ?ap 38a is maintained in an eXtended
`position until, as indicated in overshoot stage 80, a prede
`termined counterclockWise rotational velocity is attained
`Whereupon the ?ight control computer signals actuating
`apparatus 32 to pivot ?ap 38b into a predetermined eXtended
`position. In this position, ?ap 38b dampens the counter
`clockWise rotation of vehicle 10 indicated by arroW 82. The
`?ight control computer is programmed to maintain ?ap 38b
`in an eXtended position as heretofore described to dampen
`rotation of vehicle 10 until the longitudinal aXis 84 of
`vehicle 10 is substantially aligned With ?ight path 78 and the
`vehicle is in rearWard ?ight. The ?ight control computer
`then signals the actuating apparatus to eXtend both ?aps 38a
`and 38b so as to stabiliZe the ?ight path as shoWn at descent
`stage 86 of landing sequence 70.
`Those skilled in the art Will appreciate that While the
`preceding description of landing sequence 70 refers only to
`?aps 38a and 38b, an additional pair of ?aps 38c and 38d
`(FIG. 1) are provided on nose cone 26 so that ?ap assembly
`30 provides adequate control regardless of the angular
`position of vehicle 10 relative to longitudinal aXis 84 and
`?ight path 78. More particularly, it is anticipated that vehicle
`10 may at times rotate about its aXis 84 during landing
`sequence 70 in response to Which the ?ight control computer
`actuates a reaction control system (not shoWn) to perform
`landing sequence 70.
`Finally, the ?ight control computer is con?gured to adjust
`the respective positions of ?aps 38a, 38b, 38c, and 38d
`during descent stage 86 so as to stabiliZe the rearWard ?ight
`of the vehicle for landing. More particularly, the ?ight
`control computer is preferably con?gured to maintain the
`minimum angles of ?ap de?ection necessary to provide a
`pitching moment suf?cient to stabiliZe the vehicle during
`?ight and to differentially modulate the ?ap de?ection
`angles to create the required damping moments heretofore
`described. The modulation of the ?ap de?ection angles
`during descent stage 86 provide pitch and yaW control in
`rearWard ?ight to steer out ?ight dispersions caused by
`guidance and navigation errors and Winds. Accordingly, the
`present invention provides a differential ?ap modulation
`apparatus in the nose of reusable launch vehicle 10 that
`controls the rotation and stabiliZes the ?ight path of the
`vehicle during rotation and landing. Those skilled in the art
`Will appreciate that the ?ight control computer also controls
`the operation of vehicle engines 19 so as to regulate the
`descent and touchdoWn velocities of vehicle 10.
`As described, the present invention controls the position
`and orientation of vehicle 10 during rotation and landing
`sequence 70 Without requiring the consumption of propel
`lant. Accordingly, the rotation sequence may occur at a
`relatively high altitude While minimiZing any dry Weight
`additions to the vehicle due to propellant acquisition require
`ments in a nose-forWard orientation. By decreasing the
`unusable Weight carried into orbit, the payload capacity of
`reusable launch vehicle 10 is increased.
`Various other advantages of the present invention Will
`become apparent to those skilled in the art after having the
`bene?t of studying the foregoing teXt and draWings taken in
`conjunction With the folloWing claims:
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`What is claimed is:
`1. A vehicle adapted to be launched into orbit about the
`earth and to return to the earth Without jettisoning any
`portions of the vehicle, said vehicle comprising:
`an airframe; and
`a nose assembly coupled to said airframe, said nose
`assembly including a frame and a ?ap assembly having
`a plurality of independent ?aps coupled to said frame
`for independent movement from and betWeen fully
`retracted positions and fully extended positions, said
`?ap assembly further including an actuating assembly
`for moving said ?aps from and betWeen said fully
`retracted positions and said fully eXtended positions;
`and
`a ?ight control computer carried by said vehicle for
`generating guidance signals to control actuation of said
`?aps in a manner to cause said vehicle to controllably
`rotate from a nose doWn orientation during descent to
`a nose up orientation prior to landing, and to stabiliZe
`said vehicle in said nose up orientation as said vehicle
`approaches the earth.
`2. The vehicle of claim 1 Wherein said actuating assembly
`includes an actuating member coupled to one of said ?aps
`and an actuator for moving said actuating member in
`response to said guidance signals.
`3. The vehicle of claim 2 Wherein said actuating member
`has a ?rst end coupled to said one ?ap and a second end
`coupled to said actuator.
`4. The vehicle of claim 3 Wherein said actuating member
`is a telescoping arm including a ?rst member and a second
`member, said ?rst member having a ?rst end coupled to said
`actuator, said one second member having a ?rst end coupled
`to said ?rst member for movement relative thereto and a
`second end coupled to said one ?ap.
`5. The vehicle of claim 1 Wherein said one ?ap includes
`a ?rst end pivotably coupled to said frame and a second end
`movable from and betWeen said fully retracted position and
`said fully eXtended position.
`6. The vehicle of claim 1 Wherein said ?aps are circum
`ferentially disposed about said nose assembly, each of said
`?aps being coupled to said actuating means and said frame
`for movement independently from and betWeen fully
`retracted and fully eXtended positions.
`7. A nose assembly for use in a single-stage-to-orbit
`(SSTO) vehicle of the type having an airframe de?ning a
`base and a forebody, a propulsion system connected to the
`base, and a ?ight control system for generating ?ap posi
`tioning signals, said nose assembly comprising:
`a frame connectable to the forebody of the airframe;
`a ?ap assembly including a plurality of independent ?aps
`coupled to said frame for independent movement
`betWeen retracted positions and eXtended positions;
`and an actuating assembly coupled to said plurality of
`?aps for selectively independently positioning each one
`of said plurality of ?aps in response to said ?ap
`positioning signals to controllably re-orient said
`vehicle from a nose-doWn position as said vehicle
`approaches earth during descent to a nose up orienta
`tion prior to landing.
`8. The vehicle of claim 7 Wherein said frame includes a
`bulkhead, and Wherein each of said plurality of ?aps are
`pivotably coupled to said bulkhead.
`9. The vehicle of claim 7 Wherein said frame includes an
`upper bulkhead, a loWer bulkhead, and a plurality of support
`members coupled to said upper and loWer bulkheads.
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`10. The vehicle of claim 9 Wherein said nose assembly
`further includes a cap coupled to said upper bulkhead and
`Wherein said upper bulkhead, loWer bulkhead, plurality of
`support members, and plurality of ?aps each include an
`outer surface cooperating to de?ne an outer surface of said
`nose assembly When said ?aps are in said retracted positions.
`11. The vehicle of claim 7 Wherein said actuating means
`assembly includes a hub and a plurality of actuating
`members, said hub coupled to said frame and each of said
`plurality of actuating members coupled to said hub and one
`of said plurality of ?aps.
`12. The vehicle of claim 11 Wherein each of said plurality
`of actuating members comprises a telescoping arm including
`a ?rst member and a second member, said second member
`being coupled to said ?rst member for telescopic movement
`relative thereto, said ?rst member being coupled to one of
`said hub and one of said plurality of ?aps and a second
`member being coupled to the other of said hub and said one
`of said plurality of ?aps.
`13. Amethod for rotating a vehicle adapted to be launched
`into orbit and to return to earth for landing, from a nose
`forWard orientation during its ?ight toWards earth to a
`base-forWard orientation prior to landing, the vehicle includ
`ing a forebody, a base, a propulsion mechanism coupled to
`the base, a nose-forWard ?ight stabiliZation assembly, and a
`?ap assembly coupled to said forebody, said ?ap assembly
`including a plurality of ?aps and an actuating assembly for
`selectively actuating said ?aps betWeen a fully eXtended
`position and a fully retracted position, said method com
`prising the steps of:
`(a) orientating the vehicle in nose-forWard ?ight during its
`descent toWard the earth;
`(b) controlling at least one of said ?aps to cause said
`vehicle to begin rotating in a ?rst direction as said
`vehicle approaches the earth; and
`(c) selectively eXtending and retracting various ones of
`said ?aps to generate a damping moment tending to
`assist positioning and stabiliZing the vehicle in a base
`forWard orientation as said vehicle continues its descent
`to the earth.
`14. The method of claim 13 Wherein step (a) includes
`activating the nose-forWard ?ight stabiliZation assembly.
`15. The method of claim 14 Wherein step (b) includes
`deactivating the nose-forWard ?ight stabiliZation assembly.
`16. The method of claim 13 Wherein step (b) includes
`placing the propulsion mechanism in an off state.
`17. The method of claim 13 Wherein the vehicle de?nes a
`leading surface and a trailing surface When the vehicle
`rotates in said ?rst direction, Wherein a ?rst one of said ?aps
`is coupled to the leading surface of the vehicle and a second
`one of said ?aps is coupled to the trailing surface of the
`vehicle, and Wherein step (c) includes placing said ?rst one
`of said ?aps in an eXtended position, thereby generating a
`damping force acting to counter the rotational movement of
`the vehicle in said ?rst direction.
`18. The method of claim 13 further including the step of
`using said ?aps to stabiliZe the vehicle in a base-forWard
`orientation.
`19. The method of claim 18 Wherein the step of stabiliZing
`the vehicle in the base-forWard orientation includes selec
`tively placing certain ones of the ?aps in an eXtended
`position.
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`20. A single stage to orbit (SSTO) vehicle having a nose
`and a base, said vehicle comprising:
`a nose assembly;
`said nose assembly including a plurality of independent
`?aps each moveable betWeen eXtended and retracted
`positions independently of one another;
`an actuating assembly operatively associated With said
`?aps for moving said ?aps independently of one
`another betWeen said eXtended and retracted positions;
`and
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`a guidance system carried by said vehicle for controlling
`said actuating assembly such that said ?aps are con
`trolled to permit a nose forWard ?ight of said vehicle
`during a ?rst phase of descent toWard the earth, to cause
`said vehicle to rotate from said nose forWard orienta
`tion toWard a base forWard orientation, and during a
`second phase of said descent to dampen rotation of said
`vehicle and stabiliZe said vehicle in a base forWard
`orientation prior to landing.
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