United States Patent
`Mueller et al.
`
`[19]
`
`US006158693A
`Patent Number:
`Date of Patent:
`
`[11]
`[45]
`
`6,158,693
`Dec. 12, 2000
`
`[54] RECOVERABLE BOOSTER STAGE AND
`RECOVERY METHOD
`
`[75] Inventors: George E. Mueller, Kirkland, Wash.;
`Henry O. Pohl, Seabrook, Tex.
`
`[73] Assignee: Kistler Aerospace Corporation,
`Kirkland, Wash.
`
`[21] Appl. No.: 09/030,724
`[22]
`Filed:
`Feb. 25, 1998
`
`[51] Int. Cl.7 ..................................................... .. B64G 1/00
`[52] US. Cl. ................ ..
`. 244/158 R; 244/172; 244/2
`[58] Field of Search .............................. .. 244/158 R, 172,
`244/160, 2
`
`[56]
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`Maxwell W. Hunter, “Draft II The SSX Spaceship, Experi
`mental,”source unknown, Mar. 15, 1998, updated Mar. 11,
`1989, pp. 1—32.
`
`Rudi Beichel, et al., “IAF—88—229 The Next Generation
`Rocket Engines,” 39th Congress of the International Astro
`nautical Federation, Oct., 1988, 7 pages.
`
`Robert L. Staehle, et al., “Crew Transportation for the
`1990s: CommercialiZing Manned Flight with Today’s Pro
`pulsion,”World Space Foundation, 1989, 19 pages.
`
`A. P. Bruckner, et al., “IAF 92—0859 Antares: A Low Cost
`Modular Launch Vehicle Concept,” 43rd Congress of the
`International Astronautical Federation, Aug./Sep., 1992,
`pp. 1—13.
`
`D. E. Koelle, “IAA 92—0164 Cost Analysis of Singel—Stage
`(SSTO) Reusable Ballistic Launch Vehicles,” 43rd Congress
`of the International Astronautical Federation, Aug./Sep.,
`1992, pp. 1—7.
`
`3,065,596 11/1962 Schultz ................................... .. 60/353
`3,065,597 11/1962 Adamson et a1. ..................... .. 60/35.3
`
`(List continued on next page.)
`
`(List continued on next page.)
`
`FOREIGN PATENT DOCUMENTS
`
`9013481 11/1990 WIPO .
`
`OTHER PUBLICATIONS
`
`Gary C. Hudson, “Phoenix: A Commercial, Reusable
`Single—Stage Launch Vehicle,” Paci?c American Launch
`Systems, Inc., date unknown, pp. 1—13.
`Dr. William A. GaubatZ, “Space is a Place,” McDonnell
`Douglas Aerospace, date unknown, pp. 1—13.
`D.E. Koelle, et al., “The Single—Stage Reusable Ballistic
`Launcher Concept for Economic Cargo Transportation,”
`37th Congress of the International Astronautical Federa
`tion, Oct., 1986, 7 pages.
`
`Primary Examiner—J. Woodrow Eldred
`Attorney, Agent, or Firm—Baker Botts L.L.P.
`
`[57]
`
`ABSTRACT
`
`Arecoverable/reusable booster stage has a restartable center
`liquid-fueled rocket engine mounted in the aft portion of a
`vehicle body in alignment with the center axis of the body.
`The booster stage may also include two side liquid-fueled
`rocket engines mounted in the aft portion of the body in
`symmetrical relation to the center rocket engine. After
`booster stage separation, the center engine is restarted to
`direct the booster stage towards a recovery site.
`
`23 Claims, 6 Drawing Sheets
`
`AT 5)‘
`
`ov
`
`LAP
`
`4/ \\
`
`0v
`
`1c
`
`LAP
`
`m LAP
`
`Space Exploration Technologies; NEW PETITION
`Exhibit 1105
`Page 1 of 12
`
`

`

`6,158,693
`Page 2
`
`US. PATENT DOCUMENTS
`
`3,065,598 11/1962 Schultz ................................... .. 60/35.3
`3,168,266
`2/1965 Y9St --------- --
`244/138
`3,173,252
`3/1965 Zlegenhagen
`60/35-6
`3,246,467
`4/1966 Rossetw --
`60/35-6
`3,248,875
`5/1966 WOICOH
`60/35-6
`3,254,486
`6/1966 Kenny
`60/35-6
`3,254,603
`6/1966 G9u1d ~_~
`102/70
`3,262,655
`7/1966 Glllesplealr
`244/1
`3,266,237
`8/1966 Crowelhlr- eta
`-- 60/35-3
`3,286,629 11/1966 Laue ........................................ .. 102/19
`3,293,855 12/1966 Cuttill et a1. ............................ .. 60/229
`60/259
`1/1967 Webb ------- -
`3,300,981
`60/3982
`2/1967 Mangum -
`3,302,400
`102/495
`335343686 10/1970 was?“
`60/256
`3,541,796 11/1970 Morris
`.
`60/260
`3,597,923
`8/1971 Simon
`9/1971 Isley et a1. .............................. .. 60/260
`3,603,093
`3 702 683 11/1972 Foust ..................................... .. 244/153
`3’732’693
`5/1973 Chu
`60/207
`3,815,359
`6/1974 Thurston _
`60/254
`3,828,551
`8/1974 Schmidt ..
`60/204
`3,882,676
`5/1975 Schmidt ..
`60/245
`3,910,037 10/1975 Salkeld ............ ..
`60/250
`3,943,706
`3/1976 Grafwallner et al. .................. .. 60/204
`4,163,534
`8/1979 Seeger .................................. .. 244/3.22
`4,265,416
`5/1981 Jackson et al.
`244/2
`473577795 11/1982 Bastian et a1‘ '
`60004
`477967839
`1/1989 Davis ____ __
`_ 244/158 R
`4,802,639
`2/1989 Hardy et a1.
`...... .. 244/2
`4,834,324
`5/1989 (jriswell ,,,,,,, ,,
`_ 244/160
`4,844,380
`7/1989 Peoples etal. ...................... .. 244/3.22
`4,884,770 12/1989 Martin ............................... .. 244/158 R
`
`6/1993 Thole et al. .......................... .. 244/172
`5,217,188
`3/1994 Palmer ...................................... .. 244/2
`5,295,642
`4/1995 Vuillamy et a1_
`_ 60/257
`574047714
`5,456,424 10/1995 Palmer ....... ..
`244/2
`5,531,067
`7/1996 Koppel ..
`.. 60/259
`5,564,648 10/1996 Palmer
`244/2
`5,568,901 10/1996 Steinnon
`.. 244/63
`5,626,310
`5/1997 Kelly ......................................... .. 244/2
`5,661,970
`9/1997 Muller et a1. ........................... .. 60/233
`5,667,167
`9/1997 Kistler ........... ..
`244/110E
`5,689,949 11/1997 DeFreitas et a1. ................... .. 60/39.96
`
`OTHER PUBLICATIONS
`H. O. Ruppe, “Design Considerations For Future Space
`Launchers,” Acta Astraunautica(?), vol. 29, No. 9, (printed
`in Great Britian), 1993, pp. 705—722, Pergarnon Press Ltd.
`-
`‘a
`-
`Col. Simon P. Worden, et al., Single stage rocket technol
`_ H t d ,, A
`A .
`J 1 1993 8
`Ogy' ere ,0, a?”
`emspace mm”, ‘1
`>
`Pages'
`Ray R- Sm11Jan1C> et al» “Delta ChPPeri Deslgn for Support
`ability,” Aerospace America, Jul. 1993, pp. 24—27.
`Scott W. Benson, et al., “Titan III Feasibility for HL—20
`Prototype Missions,” Journal of Spacecraft and Rockets,
`Sap/Oct, 1993, pp 615_621_
`Mark K_ Sellards, “The DC_X makes its ?rst test hops A
`rocketship has landed on Earth!,” Countdown, Oct‘, 1993,
`pp 10_11
`.
`“
`.
`.
`.
`.
`.'
`'
`Dornheirn, DC—X Proving Initial Operational
`Michael
`Concepts, Avzatzon Week & Space Technology, Oct. 11,
`1993, 3 Pages
`Ivan Beckey, “Why SSTO Rocket Launch Vehicles Are NoW
`Feasible And Practical,” NASA Headquarters, Nov. 21,
`1993, PP- 1—21
`
`4,912,925
`
`4/1990 Foust ....... .., . . . . . . . . . . .
`
`. . . . . .. 60/259
`
`Arnold D_ Aldrich, “NASA’S Access To Space Study,”
`
`élacconohchle et a1‘ """"""
`13/
`/
`armouc e """""""""""" "
`/
`’
`’
`2/1992 Salkeld ......... ..
`. 244/158 R
`5,090,642
`6/1992 Bradford et a1.
`60/251
`5,119,627
`7/1992 Asaoka et a1. .
`60/204
`5,133,183
`8/1992 Leonard _ _ _ _ _
`_ _ _ __ 244/172
`571417181
`9/1992 Martin ,,,,,, ,,
`_ 244/158 R
`5,143,327
`5,158,248 10/1992 Mockovciak, Jr. ................... .. 244/160
`
`NASA Headquarters, Nov. 21, 1993, pp. 12.
`Alan W. Whilhite, et al., “Technology and Staging Effects on
`T St
`t O b.t S t
`,, J
`l
`S
`a,
`W0‘ age‘ 0‘ r 1
`Y5 ems’ Gum“ Of Pacecm? ‘1”
`Rockem Jan~/Feb~>_1994> W 31__38'
`_
`Steven J. IsakoW1tZ, “International Reference Guide to
`Space Launch Systems,” American Institute of Aeronautics
`and Astronautics, 1991, 295 pages.
`
`Space Exploration Technologies; NEW PETITION
`Exhibit 1105
`Page 2 of 12
`
`

`

`U.S. Patent
`
`Dec. 12, 2000
`
`Sheet 1 0f 6
`
`6,158,693
`
`/( \wxi
`
`FIG. 7
`
`Space Exploration Technologies; NEW PETITION
`Exhibit 1105
`Page 3 of 12
`
`

`

`Space Exploration Technologies; NEW PETITION
`Exhibit 1105
`Page 4 of 12
`
`

`

`U.S. Patent
`
`Dec. 12, 2000
`
`Sheet 3 0f 6
`
`6,158,693
`
`520
`
`47
`
`52|e
`
`52re
`
`520
`
`E
`
`III
`
`64/
`
`2“)
`42
`
`:V
`x
`66
`
`44
`
`i
`
`45
`
`'
`
`1'
`
`60
`
`FIG. 3
`
`Space Exploration Technologies; NEW PETITION
`Exhibit 1105
`Page 5 of 12
`
`

`

`U.S. Patent
`
`Dec. 12,2000
`
`Sheet 4 0f6
`
`6,158,693
`
`It 0
`
`O is
`
`O is
`
`52le
`
`46
`52le
`
`4g
`
`44
`
`52re
`
`FIG. 4
`
`Space Exploration Technologies; NEW PETITION
`Exhibit 1105
`Page 6 of 12
`
`

`

`U.S. Patent
`
`Dec. 12,2000
`
`Sheet 5 0f6
`
`6,158,693
`
`Space Exploration Technologies; NEW PETITION
`Exhibit 1105
`Page 7 of 12
`
`

`

`U.S. Patent
`
`Dec. 12,2000
`
`Sheet 6 0f6
`
`6,158,693
`
`F IG. 6
`
`0v
`
`LAP
`
`1c
`A
`m LAP
`
`Space Exploration Technologies; NEW PETITION
`Exhibit 1105
`Page 8 of 12
`
`

`

`1
`RECOVERABLE BOOSTER STAGE AND
`RECOVERY METHOD
`
`TECHNICAL FIELD OF THE INVENTION
`
`The present invention relates to launch vehicles and, in
`particular, to recoverable booster stages that are used to
`assist orbital vehicles in attaining orbit or heading to outer
`space and to a method of recovering a booster stage for
`reuse.
`
`BACKGROUND OF THE INVENTION
`
`Multi-stage launch vehicles are Widely used to carry
`payloads into orbit and propel space vehicles into outer
`space. One or more booster stages accelerate an orbital stage
`vehicle toWards space. The orbital stage vehicle carries the
`payload into orbit and, in some cases, beyond for travel in
`outer space. After each booster stage has served its purpose
`in attaining a certain velocity, it is separated from the neXt
`stage (Which may be another booster stage or the orbital or
`space vehicle) and is alloWed to fall back to earth, almost
`alWays into an ocean. In these eXisting launch vehicles,
`recovery of the booster stage is impractical, if not impos
`sible.
`The increasing use of orbiting communications satellites,
`the planned construction of manned space stations, the
`supplying of the eXisting space station, and other space
`activities has already required, and Will in the future require,
`very large investments in launch vehicles that are used only
`once. Although the ?eet of NASA space shuttles are prima
`rily reusable, the costs of producing and operating manned
`recoverable/reusable vehicles such as the space shuttle is
`prohibitive.
`
`10
`
`15
`
`25
`
`SUMMARY OF THE INVENTION
`
`35
`
`An object of the present invention is to reduce the costs
`of placing vehicles or payloads in earth orbits and in space
`and, in particular, to provide a recoverable/reusable booster
`stage for a launch vehicle. Another object is to enable a
`booster stage to be recovered at any desired site, including
`near a ground launch site. Yet another object is to enable a
`booster stage to land in a reusable condition near the launch
`site, thereby eliminating the need to transport the recovered
`vehicle over a long distance and permitting a quick turn
`around time for another launch.
`The foregoing objects are attained, in accordance With the
`present invention, by a recoverable/reusable booster stage
`having a restartable, liquid-fueled center rocket engine
`mounted in the aft portion of a structural/aerodynamic body
`in alignment With the center aXis of the body. In a particular
`embodiment, the booster stage includes tWo or more addi
`tional side rocket engines mounted in the aft portion of the
`body in symmetrical relation to the center rocket engine, so
`that the thrust aXes of the side engines generally lie in a plane
`that includes the center aXis of the body. In one embodiment,
`tWo side rocket engines may be placed in a line With the
`restartable center engine. In another embodiment, four side
`rocket engines may be placed in an “X” con?guration With
`the restartable engine in the center. The invention may use
`any number of side engines that are integral to the main
`structural/aerodynamic body or provided as separate strap
`ons.
`Although it is possible to provide attitude control thrusters
`to aid in steering the booster stage for recovery, the direction
`of thrust of the center engine may be controllable so that the
`vehicle is steerable by the center engine. The side engines
`
`45
`
`55
`
`65
`
`6,158,693
`
`2
`are liquid-fueled engines to minimiZe the costs for reuse, but
`may also be solid fuel rocket engines.
`An important aspect of one embodiment of the present
`invention is that the three engines (tWo side engines and one
`center engine) are aligned along an aXis that is transverse to
`the center aXis of the vehicle body and that the center engine
`lies on the center aXis of the body. This arrangement alloWs
`the three engines to propel the launch vehicle from launch to
`a separation point With the combined thrust of the three
`engines acting on or near the center of gravity of the launch
`vehicle during ascent. After booster stage engine shut-doWn,
`stage separation, and restarting of the center engine, the
`center engine thrust also acts on or near the center of gravity
`of the booster stage during descent.
`Advantageously, the side engines are mounted at a cant
`(e.g., siX degrees) such that at lift-off their thrust aXis
`intersects the center of gravity of the launch vehicle. This
`arrangement, together With positioning the center engine for
`thrust along the center aXis of the vehicle, avoids compli
`cated dynamics from the thrust of all engines, and thereby
`facilitates control of the ascent trajectory. The center engine
`and side engines may be mounted in single or multiple aXis
`gimbals to control the launch vehicle.
`The center engine and the side engines may be mounted
`on one or more transverse beams. A three engine in a line
`con?guration may have a single transverse beam, Whereas a
`?ve engine “X” con?guration may have tWo perpendicular
`transverse beams. The body, typically, has a tubular
`structural/aerodynamic circular cylindrical Wall and a thrust
`ring attached to an aft portion of the Wall. The thrust beam
`is connected to the thrust ring by a plurality of compression
`struts oriented obliquely to the center ads. For eXample, the
`compression struts may include side struts connected
`betWeen portions of the beam proximate to the ends of the
`beam and the thrust ring and center struts connected betWeen
`a center portion of the beam and the thrust ring.
`The engines can be started at lift-off using compressed
`oxygen-enriched air from a pad-based starting system.
`Restarting the center engine in ?ight for propulsion of the
`booster stage upon descent is accomplished With a start
`cartridge. Start cartridges may also be used at launch on all
`engines of the booster stage, in Which case, the center engine
`has tWo start cartridges, one for launch and the other for
`restarting after separation of the recoverable booster stage.
`Aparticular embodiment of the present invention includes
`a restartable center liquid-fueled rocket engine mounted in
`the aft portion of the body in alignment With the center aXis
`of the body, the center engine being mounted for selective
`adjustment of the thrust aXis so that the booster stage is
`steerable, and tWo side liquid-fueled rocket engines mounted
`in ?Xed positions in symmetrical relation to the center rocket
`engine so that the thrust aXes of the side engines de?ne a
`plane that includes the center aXis of the body. Each side
`engine is oriented such that its thrust aXis at lift-off approxi
`mately intersects the center of gravity of the launch vehicle.
`The center engine and the side engines are mounted on a
`transverse beam, Which is connected by several compression
`struts to a thrust ring attached to an aft portion of the Wall,
`the struts being oriented obliquely to the center aXis. The
`compression struts include side struts connected betWeen
`portions of the beam proximate to the ends of the beam and
`the thrust ring and center struts connected betWeen a center
`portion of the beam and the thrust ring. The center engine
`has tWo start cartridges, one for launch and the other for
`restarting for descent.
`There is also provided, in accordance With the present
`invention, a method of launching a payload into space that
`
`Space Exploration Technologies; NEW PETITION
`Exhibit 1105
`Page 9 of 12
`
`

`

`6,158,693
`
`3
`uses a multi-stage launch vehicle that includes an orbital or
`space vehicle and a recoverable/reusable booster stage. The
`booster stage includes a restartable and steerable liquid
`fueled center rocket engine mounted in an aft portion of a
`body in alignment With a center axis of the body and at least
`tWo side liquid-fueled rocket engines in the aft portion of the
`body in symmetrical relation to the center rocket engine. The
`launch vehicle ascends from a ground launch site using three
`or more engines and attains a predetermined velocity for
`stage separation, at Which point the engines of the booster
`stage are shut doWn. The orbital vehicle then separates from
`the booster stage. Next, the center engine of the booster
`stage restarts and the booster stage ?ies along a predeter
`mined path toWard a recovery site, most preferably a ground
`site, by controlling the thrust direction of the center engine.
`The recovery site may be virtually anyWhere Within a
`reasonable distance of the launch site. Ground transport
`vehicles, helicopters, or other vehicles can be used to bring
`the booster stage back to the launch site for reuse. One
`advantage of having a booster stage that is restarted and
`?oWn under control after stage separation is the ability to
`return the booster stage to a ground recovery site near the
`launch site. For example, the restarted booster stage may be
`?oWn back uprange along a ?ight path that returns it to a
`location proximate to the launch pad. A margin of error
`ensures that the booster stage does not land on the launch
`facility or at other undesirable or populated sites. The
`booster stage includes deployable parachutes and deploy
`able in?atable landing cushions. At a predetermined point
`along the return path, the center engine of the booster stage
`is shut doWn. After sloWing of the vehicle by aerodynamic
`forces, the parachutes and the landing cushions are
`deployed, and the booster stage settles to a landing at the
`recovery site in a reusable condition.
`There are various trade-offs to be made in designing the
`?ight path for recovery near the launch site. One involves
`the rate of climb at ascent. In order to minimiZe the amount
`of fuel needed to return to the launch site, the ?ight path at
`ascent may be kept steep, so that the vehicle does not have
`to return from a great distance. The orbital vehicle may then
`require more thrust, a longer burn time, or both to achieve
`sufficient orbital velocity.
`Other technical advantages are readily apparent to one
`skilled in the art from the folloWing ?gures, description, and
`claims.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`For a more complete understanding of the present
`invention, and for further features and advantages, reference
`is noW made to the folloWing description, taken in conjunc
`tion With the accompanying draWings, in Which:
`FIG. 1 is a side pictorial vieW of a launch vehicle that
`includes a booster stage embodying the present invention,
`the launch vehicle being vieWed from a vantage point
`slightly above the forWard end;
`FIG. 2 is a generally schematic cut-aWay vieW of the aft
`portion of the booster stage of FIG. 1;
`FIG. 3 is a generally schematic vieW of the aft portion of
`the booster stage, taken along the lines 3—3 of FIG. 2, With
`the tanks removed;
`FIG. 4 is a generally schematic end vieW of the booster
`stage;
`FIG. 5 is a perspective vieW, looking from a point of vieW
`to the side and beloW, of the structure by Which the engines
`are mounted and connected to the body of the booster stage;
`and
`
`4
`FIG. 6 is a pictorial diagram of the launch, stage
`separation, and recovery of the booster stage.
`
`DETAILED DESCRIPTION OF THE
`INVENTION
`
`The launch vehicle includes an orbital vehicle (OV) and
`a booster stage or launch assist platform (LAP), Which
`propels the OV toWards an orbit around the earth. The
`juncture of the LAP With the OV is indicated by the line J.
`The tWo-stage combination LAP/OV is designed primarily
`to take payloads into earth orbit. The LAP can also be used
`alone or With one or more additional booster stages to assist
`a space vehicle in reaching outer space. The present inven
`tion contemplates the recovery of at least one booster stage
`folloWing ascent of the launch vehicle.
`The LAP has a body that is essentially a tubular structural/
`aerodynamic shell 10 of circular cylindrical shape, Which is
`constituted in major part by internally ribbed tubular panels
`12, 14 and 16 of a composite material (?bers dispersed in a
`resin binder). The outer peripheral Wall 17 of a main
`aluminum liquid oxygen (LOX) tank is integrated into the
`Wall 10 and is thermally isolated from the panels 14 and 16
`by aluminum skirts 18 and 20. Various systems and equip
`ment packages (e.g., for engine control, ?ight path control,
`altitude control, communications, and the like) are mounted
`Within the shell.
`FIG. 2 illustrates an annular liquid propellant tank (LP)
`that occupies a region just above the engines . A hole in the
`center of the tank LP contains an aluminum LOX retention
`tank (LRT), through Which LOX from the main tank (LOX)
`passes on its Way to the engines. The LOX in the main tank
`LOX is consumed on ascent. At engine shut-doWn prior to
`stage separation, valves in the conduits 30 from the main
`tank LOX to the retention tank LRT are closed to isolate a
`supply of LOX in the capture tank for consumption by the
`center engine When it is restarted and run to propel the LAP
`to its recovery destination. The tanks LOX and LRT are
`pressuriZed by pressure tanks (not shoWn), Which deliver
`pressuriZed gas to the tanks to supply LOX to the engines.
`A center rocket engine 40 mounts adjacent the aft end of
`the body in alignment With (center of the noZZle 42 centered
`on) the center axis CA of the vehicle body 10. In a particular
`embodiment, tWo side engines 44 and 46 are mounted
`symmetrically With respect to the center axis CA and cen
`tered on axes through the centers of the respective noZZles
`45 and 47 that lie in a plane that also includes the center axis
`of the body. LAP may also include additional side engines
`mounted Within vehicle body 10 or provided as strap-on
`boosters. For example, LAP may include four side engines
`arranged in an “X” con?guration around center engine 40.
`Although side engines 44 and 46 may be mounted on
`gimbals for adjustments of their orientations to con?gure the
`LAP for a particular mission, such as for use With different
`orbital vehicles, the side engines may be ?xed in ?ight to
`provide thrust along axes that pass through the center of
`gravity of the launch vehicle (LAP and OV) at lift-off. The
`center engine 40 is mounted on gimbals and is controlled in
`?ight to steer the launch vehicle along a desired trajectory on
`ascent and to steer the LAP after stage separation and restart
`of the center engine 40 for poWered ?ight to a recovery site.
`As illustrated in more detail in FIGS. 3, 4, and 5, the
`engines 40, 44, and 46 are mounted on a common transverse
`beam 50, Which is a Weldment of several pieces, each of
`Which is of a manageable siZe for fabrication and some of
`Which, such as engine mounts, are the same (at least When
`the three engines are identical). Other embodiments that
`
`10
`
`15
`
`25
`
`35
`
`45
`
`55
`
`65
`
`Space Exploration Technologies; NEW PETITION
`Exhibit 1105
`Page 10 of 12
`
`

`

`6,158,693
`
`10
`
`15
`
`25
`
`5
`include additional side engines may include additional trans
`verse beams 50. For example, a ?ve engine “X” con?gura
`tion may include tWo perpendicular transverse beams 50.
`Alternatively, LAP may not include any transverse beams
`50, but instead place engines 44 and 46 is side mounted
`canisters or strap-ons. The present invention contemplates
`any number, arrangement, and mounting of side engines
`about a restartable center engine 40, including one embodi
`ment With no side engines.
`As can best be seen in FIG. 5 shoWing a particular
`embodiment of a three engine con?guration, the beam 50 is
`connected to the LAP shell 10 by a system of compression
`struts 52, each of Which is connected betWeen the beam 50
`and a main thrust ring 54. The thrust ring 54 supports the
`shell 10 of the LAP and directly carries the tank LP by
`support brackets 56. The compression struts are arranged in
`groups, the struts 52c of one group being connected to the
`center portion of the beam 50 and the struts of tWo other
`groups 52re and 52le being connected to the respective right
`and left ends of the beam 50. The compression struts extend
`obliquely at diverse angles relative to the center axis CA of
`the shell 10 and are connected to the ring 54 at approxi
`mately equally circumferentially spaced-apart points. The
`beam 50 is strong and stiff and is, therefore, able to carry the
`large forces exerted by the engines With little de?ection. The
`ring 54 is subject to high tensile forces exerted by the struts
`52 and is designed accordingly. The struts transmit the thrust
`forces of the engines from the beam 50 to the ring. The shell
`10 is strong and stiff axially, thus subjecting the ring to a
`reaction load acting parallel to the center axis and distributed
`substantially uniformly about the circumference of ring 54.
`The launch vehicle is launched from a ground launching
`facility by starting the engines by means of start cartridges
`60 and 62 for the side engines 44 and 46, respectively, and
`start cartridge #1 64 for center engine 40 (the start cartridges
`are shoWn schematically in FIG. 3). Alternatively, the
`engines may be started for launch using compressed gas or
`other suitable ground-based equipment.
`NoW referring to FIG. 6, the LAP and OV are ?oWn along
`a predetermined ascent trajectory AT to a predetermined
`location for stage separation. The supply valves for liquid
`propellant and liquid oxygen to the engines are closed,
`thereby shutting doWn all engines 40, 44, and 46. The valves
`in the conduits 30 connecting the main tank LOX to the
`retention tank LRT are also closed to capture LOX in the
`retention tank. At this point, the contents of the main tank
`LOX have been largely used up. Explosive bolts or other
`suitable mechanism releases the OV from the LAP, and
`thrusters on the OV are ?red to move the OV along a
`separation distance SD far enough from the LAP to permit
`a rocket engine on the OV to be safely started, Whereupon
`the OV is accelerated for further ascent along an orbital
`entry path OEP into orbit.
`As soon as the OV is clear of the LAP, the center engine
`40 on the LAP is started by opening the valves in the LOX
`55
`lines from the main tank LOX to the retention tank LRT and
`from the retention tank to the center engine 40, opening the
`line from the propellant tank LP to the engine, and ?ring the
`start cartridge #2 66 (FIG. 3). Having been considerably
`lightened by separation of the OV and expenditure of liquid
`propellant and LOX, the center engine 40 is suf?cient to
`direct the LAP to a suitable recovery site. By controlling the
`thrust magnitude and direction of the center engine 40, the
`LAP can be ?oWn along any desired trajectory DT to a
`recovery site, Which can be doWnrange but is, preferably,
`uprange and proximate to the launch site. When the LAP
`reaches a location along the trajectory DT uprange from the
`
`6
`recovery site, it is maneuvered by the main engine to an
`approach path that Will take it in a free fall to a location
`Where parachutes P can be deployed. At a suitable position
`along the approach path, the engine 40 is shut doWn, and
`When the set location for parachute deployment is reached,
`parachutes P are released from compartments in the LAP. At
`a suitable time or height, in?atable cushions IC carried by
`the LAP are deployed. The cushions absorb the impact of
`landing and keep the LAP itself from touching the ground.
`The ability to recover the LAP for reuse offers consider
`able savings in costs per mission, the savings increasing With
`the number of times that the LAP can be reused. Additional
`savings are afforded by recovering the LAP near the launch
`station to provide quick and relatively loW cost transport of
`the LAP to the launch station.
`Although the present invention has been described in
`several embodiments, a myriad of changes, variations,
`alterations, transformations, and modi?cations may be sug
`gested to one skilled in the art, and it is intended that the
`present invention encompass such changes, variations,
`alterations, transformations, and modi?cations as fall Within
`the spirit and scope of the appended claims.
`What is claimed is:
`1. A launch vehicle, comprising:
`an upper stage operable to carry a payload; and
`a booster stage having a body With a longitudinal center
`axis and an aft portion, the booster stage further com
`prising a restartable center rocket engine mounted in
`the aft portion of the body in alignment With the center
`axis of the body, Whereby the center rocket engine
`restarts after separation to direct the booster stage to a
`recovery site.
`2. The launch vehicle of claim 1, further comprising tWo
`or more side rocket engines mounted in the aft portion of the
`body in symmetrical relation to the center rocket engine.
`3. The launch vehicle of claim 1, further comprising
`means for adjusting the direction of thrust of the center
`engine so that the vehicle is steerable.
`4. The launch vehicle of claim 1, Wherein the center
`engine is a liquid-fueled engine.
`5. The launch vehicle of claim 2, Wherein the side engines
`are liquid-fueled engines.
`6. The launch vehicle of claim 2, Wherein the side engines
`are mounted such that at lift-off their thrust axes intersect the
`center of gravity of the launch vehicle.
`7. The launch vehicle of claim 2, Wherein the center
`engine and the side engines are liquid-fueled engines and are
`mounted on a transverse beam.
`8. The launch vehicle of claim 7, Wherein the body has a
`cylindrical Wall and a thrust ring attached to an aft portion
`of the Wall, and Wherein the beam is connected to the thrust
`ring by a plurality of compression struts oriented obliquely
`to the center axis.
`9. The launch vehicle of claim 8, Wherein the compression
`struts comprise:
`a plurality of side struts connected betWeen portions of the
`beam proximate to the ends of the beam and the thrust
`ring; and
`a plurality of center struts connected betWeen a center
`portion of the beam and the thrust ring.
`10. The launch vehicle of claim 1, Wherein the center
`engine has tWo start cartridges, one for launch and the other
`for restarting after separation of the booster stage from
`another stage of the launch vehicle.
`11. A booster stage of a launch vehicle, comprising:
`a body having a longitudinal center axis and an aft
`portion; and
`
`35
`
`45
`
`65
`
`Space Exploration Technologies; NEW PETITION
`Exhibit 1105
`Page 11 of 12
`
`

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`6,158,693
`
`7
`a restartable center liquid-fueled rocket engine mounted
`in the aft portion of the body in alignment With the
`center axis of the body, the center engine being
`mounted for selective adjustment of the thrust aXis so
`that the booster stage is steerable, Whereby the center
`rocket engine restarts after separation to direct the
`booster stage to a recovery site.
`12. The booster stage of claim 11, further comprising tWo
`or more side liquid-fueled rocket engines mounted in the aft
`portion of the body in symmetrical relation to the center
`rocket engine.
`13. The booster stage of claim 12, Wherein each side
`engine is oriented such that at lift-off its thrust aXis intersects
`the center of gravity of the launch vehicle.
`14. The booster stage of claim 12, Wherein the center
`engine and the side engines are mounted on a transverse
`beam.
`15. The booster stage of claim 14, Wherein the body has
`a cylindrical Wall and a thrust ring attached to an aft portion
`of the Wall, and Wherein the beam is connected to the thrust
`ring by a plurality of compression struts oriented obliquely
`to the center aXis.
`16. The booster stage of claim 15, Wherein the compres
`sion struts comprise:
`a plurality of side struts connected betWeen portions of the
`beam proXimate to the ends of the beam and the thrust
`ring; and
`a plurality of center struts connected betWeen a center
`portion of the beam and the thrust ring.
`17. The booster stage of claim 11, Wherein the center
`engine has tWo start cartridges, one for launch and the other
`for restarting after separation of the booster stage from
`another stage of the launch vehicle.
`18. A method of recovering a booster stage of a launch
`vehicle, comprising:
`
`10
`
`15
`
`25
`
`8
`launching a launch vehicle from a launch site by starting
`a center engine of a booster stage;
`shutting doWn the center engine;
`separating the booster stage;
`restarting the center engine using a start cartridge; and
`directing the booster stage toWards a recovery site by
`controlling the thrust direction of the restarted center
`engine.
`19. The method of claim 18, Wherein the booster stage
`further comprises tWo or more side liquid-fueled rocket
`engines mounted in symmetrical relation to the center rocket
`engine and furth