Abstract:
A launch vehicle mounting system for use in launching either of first and second launch vehicles having different booster diameters is disclosed. In one embodiment, the launch vehicle mounting system includes a mounting frame and a plurality of arms pivotally interconnectable to the mounting frame for supporting either of the first and second launch vehicles positionable thereon. In particular, the launch vehicle mounting system of the present invention is adapted to support either the first or the second launch vehicle as the arms are at least radially adjustable relative to the mounting frame to at least first and second radial positions corresponding to the booster diameters of the first and second launch vehicles.

Description:
RELATED APPLICATIONS 
     This application is a continuation of Ser. No. 08/856,530 filed May 14, 1997 U.S. Pat. No. 5,974,939, and a divisional of U.S. patent application Ser. No. 08/627,565, filed Apr. 4, 1996 now U.S. Pat. No. 5,845,875, entitled “Modular Launch Pad System”, which is a continuation of U.S. patent application Ser. No. 08/245,178, filed May 17, 1994, now abandoned, which is a continuation-in-part of U.S. patent application Ser. No. 08/236,298, filed on May 2, 1994, now abandoned. 
    
    
     FIELD OF THE INVENTION 
     This invention relates generally to an apparatus for supporting launch vehicles, and more particularly to a launch vehicle mounting system. 
     BACKGROUND OF THE INVENTION 
     For many years, rockets have been used to launch payloads into space. Increasingly, uses of non-military satellites has expanded the opportunities for defense companies to develop non-military launch applications using formerly military launch technologies. This has created a need for systems suitable of launching satellites from sites throughout the world, including remote locations. 
     The exhaust gases from launch vehicles exit at high temperatures and pressures in excess of 1000 psi. To prevent destruction of the launch vehicle, the gases are vented away from the motor base through ducts positioned below the first stage motors. Because of the large gas volume and pressures, traditional launch pads have been permanent constructions made of reinforced concrete built in place in deep holes below ground surface, relying on the surrounding earth to provide lateral support to the duct walls. This type of construction requires the removal of substantial amounts of soil to prepare a suitable base. The resulting construction, which is made from concrete and steel, is thus a permanent structure. 
     In addition, each launch site was typically designed for a specific launch system and extensive retrofitting was required to adapt a launch pad for use with a larger or smaller launch motor. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a launch pad system which can be constructed from preconstructed modular units on the surface of the ground without any significant subsurface excavation. 
     It is another object of the present invention to provide a launch pad system which is easily assembled from preconstructed modules and which can be dismantled after use. 
     It is a further object of the invention to provide a modular launch pad system in which the modules are sized to allow easy transportation and handling using conventional flat bed trucks and cranes. 
     It is still a further object of this invention to provide a highly mobile launch support system which can be assembled from components which can be moved onto the construction site with conventional flatbed vehicles and assembled with conventional heavy lifting equipment. 
     It is another object of the present invention to provide a modular launch pad system which can be easily repaired. 
     It is another object of the present invention to provide a launch pad blast deflector for deflecting the exhaust gases of a launch vehicle during the launching thereof. 
     It is yet another object of the invention to provide a modular unit and connectors for connecting modular units to one another. 
     It is still another object of the invention to provide a launch vehicle mounting means which can be adjusted to accept a wide variety of launch vehicle sizes. 
     According to the invention there is a provided a launch pad for a launch vehicle, comprising a frame, a plurality of slab means separably connected to the frame by means of slab connectors; and a launch vehicle mounting means having an exhaust gas opening for supporting a launch vehicle, the launch pad defining exhaust gas channeling means in flow communication with the exhaust gas opening of the mounting means for channeling launch exhaust gases of the launch vehicle away from the vehicle. 
     Each slab means can include a reinforced concrete slab having opposed major surfaces, and connecting means embedded in the concrete slab complimentarily engageable with the slab connectors. 
     The slab means can include a peripheral frame secured to the periphery of the concrete slab. 
     The frame can comprise U-shaped channel sections connected to one another to form a frame, the legs of the U being directed inwardly to engage the major surfaces of the slab. 
     At least one of the legs of the channel sections can be partially embedded in the concrete slab to provide the slab means with at least one smooth major face. 
     Each connecting means can comprise an internally threaded sleeve extending into the slab from one of the major surfaces of the slab. 
     The sleeve can extend through the slab between the major surfaces of the slab. The ends of the sleeves can lie flush with the major surfaces of the slab. 
     Each connecting means can comprise an internally threaded sleeve extending into the frame through at least one of the legs of the U shaped channel. 
     The launch pad can include a blast deflecting means for deflecting launch vehicle exhaust gases into the channeling means. 
     The blast deflecting means can comprise at least one angled deflector plate having a ramp-like concave surface. 
     The plate can be a steel plate coated with an insulating ceramic material on the concave surface. 
     The channeling means can comprise at least one laterally extending duct forming a flow path extending away from the blast deflecting means. 
     The channeling means can comprise two ducts extending outwardly in opposite directions from the blast deflecting means, and wherein the blast deflecting means can include a pair of angled deflector plates each having a ramp-like concave surface, the plates being connected along upper edges of the plates to form are vertex. 
     The launch vehicle mounting means can include a plurality of vertically extending pillars and on adapting means mounted on the pillars for supporting a launch vehicle. 
     The adapting means can comprise an adapter ring removably engagebly with upper ends of the pillars. 
     The adapting means can comprise a plurality of pedestals having horizontal upper faces, the pedestals being movably mounted relative to one another. 
     Further according to the invention there is provided a building unit comprising a concrete slab having opposed major surfaces; a plurality of longitudinally and transversely extending reinforcement bars embedded in the concrete slab; a plurality of internally threaded sleeves embedded in the slab, the sleeves extending into the slab from one of the major surfaces to define threaded channels in the slab. 
     The building unit can include a peripheral frame made of U-shaped channel sections connected to one another to form a frame, wherein the legs of the U are directed inwardly to engage the major surfaces of the slab, at least one of the legs of the channel sections being partially embedded in the slab so that the outer surfaces of said legs lie flush with the portion of the major surface extending between said legs. 
     The sleeves can extend through the slab between the major surfaces. 
     The sleeves can extend through at least one of the legs of the U-shaped channel sections and into the slab. 
     Still flirter according to the invention there is provided a building unit, comprising a concrete slab having opposed major surfaces; a peripheral frame made of U-shaped channel sections connected to one another to form a frame, wherein the legs of the U are directed inwardly to engage the major surfaces of the slab, at least one of the legs of the channel sections being partially embedded in the slab so that the outer surfaces of said legs lie flush with the portion of the major surface extending between said legs; a plurality of longitudinally and transversely extending reinforcement bars embedded in the concrete slab; and a plurality of connecting means secured to the slab or to a leg of the U-shaped channel sections. 
     The connecting means can comprise internally threaded sleeves embedded in the slab. 
     Still further according to the invention there is provided a vehicle exhaust gas deflector assembly comprising at least one angled deflector plate having a ramp-like concave surface. 
     The plate can be a steel plate coated with an insulating ceramic material on the concave surface. 
     The deflector assembly can include a pair of angled deflector plates each having a ramp-like concave surface, the plates being connected along upper edges of the plates to form a vertex. 
     Still further according to the invention there is provided a launch vehicle mounting means comprising a plurality of vertically mounted pillars and an adapting means mounted on the pillars for supporting a launch vehicle. 
     The adapting means can comprise an adaptor ring removably engageable with upper ends of the pillars. 
     The adapting means can instead comprise a plurality of pedestals having horizontal upper faces, the pedestals being movably mounted relative to one another. The adapting means can include a plurality of arms pivotally connected to a mounting frame and wherein the pedestals can be pivotally connected to the arms. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an isometric view of a prior art launch pad; 
     FIG. 2 is an isometric view of the preferred embodiment of a launch pad of the present invention; 
     FIG. 3 is an end view of the launch pad of FIG. 2; 
     FIG. 4 is a side view of the same launch pad shown in FIG. 3; 
     FIG. 5 is a top view of the launch pad shown in FIG. 4; 
     FIG. 6 is an isometric view of a modular building unit in accordance with the invention; 
     FIG. 7 is a sectional view through the building unit of FIG. 6 along the line I—I; 
     FIG. 8 is an isometric view of a frame of the launch pad; 
     FIG. 9 is a detailed isometric view of part of the frame of FIG. 8; 
     FIG. 10 is a detailed sectional view through a longitudinally extending T-bar and a building unit in accordance with the invention; 
     FIG. 11 is a detailed isometric view of part of the frame of the launch pad in accordance with the invention; 
     FIG. 12 is a schematic side view of a bolt connected to a longitudinally extending bar showing an insulating covering in cross section; 
     FIG. 13 is a schematic sectional side view along the line II—II of FIG. 9; 
     FIG. 14 is a schematic plan view of the portion of the frame of FIG. 13; 
     FIG. 15 is a side view of the frame of FIG. 8; 
     FIG. 16 is an isometric view of the launch pad of FIG. 2 in a partially assembled state; 
     FIG. 17 is a sectional plan view through a pair of building units connected by a vertically extending T-bar in accordance with the invention; 
     FIG. 18 is an exploded isometric view of the units and T-bar of FIG. 17; 
     FIG. 19 is a schematic side view of a vertically extending T-bar, a pair of horizontally extending connector plates and a horizontally extending T-beam for securing horizontally extending building units to vertically extending building units in accordance with the invention; 
     FIG. 20 is a plan view of the launch pad in accordance with the invention, in a partly assembled state; 
     FIG. 21 is a sectional view of a vertically extending unit connected to a horizontally extending unit by a connector plate in accordance with the invention; 
     FIG. 22 is a sectional view through a vertically extending unit connected to a horizontally extending unit by a connector plate in accordance with another embodiment of the invention; 
     FIG. 23 is a side view of the launch pad in accordance with the invention; 
     FIG. 24 is a partially exploded isometric view of the launch pad of FIG. 23; 
     FIG. 25 is a sectional view through a slanted unit and bracket system for connecting platform plates to the slanted unit in accordance with the invention; 
     FIG. 26 is a plan view of the slanted unit and brackets of FIG. 25; 
     FIG. 27 is a partially exploded isometric view of the launch vehicle mounting platform in accordance with the invention; 
     FIG. 28 is a detailed schematic side view of a triangular unit attached to plates and a T-bar; 
     FIG. 29 is a sectional end view of part of the launch vehicle mounting platform in accordance with the invention; 
     FIG. 30 is a partial cutaway isometric view of the launch pad in accordance with the invention; 
     FIG. 31 is a plan view of a launch mount base ring forming part of the pad of FIG. 2; 
     FIG. 32 is a side view of the ring of FIG. 31; 
     FIG. 33 is an end view of a pillar forming part of a launch mount of the pad of FIG. 2; 
     FIG. 34 is a side view of the pillar of FIG. 33; 
     FIG. 35 is a partial cutaway isometric view of the launch mount and deflectors of the pad of FIG. 2; 
     FIG. 36 is a schematic end view of the launch mount and deflectors of FIG. 35; 
     FIG. 37 is a schematic side view of the launch mount and deflectors of FIG. 35; 
     FIG. 38 is a detailed sectional side view of the vertex of a pair of deflectors in accordance with the invention; 
     FIG. 39 is a schematic side view of the lower terminal end of one of the deflectors of FIG. 35; 
     FIG. 40 is a schematic sectional side view of a launch pad showing a water cooling system; 
     FIG. 41 is an end view of the launch pad of FIG. 2; 
     FIG. 42 is a schematic side view of the launch mount in accordance with the invention; 
     FIG. 43 is a plan view of a launch ring forming part of the launch mount of FIG. 42; 
     FIG. 44 is a side view of the launch ring of FIG. 43; 
     FIG. 45 is an isometric view of another embodiment of a launch ring in accordance with the invention; 
     FIG. 46 is an isometric view of yet another embodiment of a launch ring in accordance with the invention; 
     FIG. 47 is an isometric view of still another embodiment of a launch ring in accordance with the invention; 
     FIG. 48 is a cutaway isometric view of another embodiment of a launch pad in accordance with the invention; 
     FIG. 49 is an isometric view of an adaptor forming part of the launch pad illustrated in FIG. 48; 
     FIG. 50 is a side view of the adaptor of FIG. 49; 
     FIG. 51 is a schematic side view of an adaptor with alignment balls; 
     FIG. 52 is a schematic side view of an adaptor with explosive bolts; 
     FIG. 53 is an isometric view of another embodiment of a launch pad in accordance with the invention; 
     FIG. 54 is an isometric view of yet another embodiment of a launch pad in accordance with the invention; 
     FIG. 55 is a sectional side view of still a further embodiment of a launch pad in accordance with the invention; 
     FIG. 56 is an isometric view of the launch pad of FIG. 55; 
     FIG. 57 is an isometric view of yet another embodiment of a launch pad in accordance with the invention; and 
     FIG. 58 is a sectional side view of the launch pad of FIG.  57 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Launch pads have, to date, involved immovable concrete structures built into the ground as illustrated in FIG.  1 . This invariably involves a great deal of excavation, typically of the order of 15 feet deep, requiring much preparation and resulting in a fixed structure. Generally, the launch pad is cast on site. 
     In contrast, the launch pad of the present invention is made up of a series of portable units, as will be described in greater detail below and as is illustrated in FIG.  2 . FIG. 2 illustrates the launch pad  10  having a launch vehicle mounting platform  12  and laterally extending exhaust gas channeling means in the form of ducts  14 . An umbilical mast  16  carrying two umbilical cords  18 ,  20  is mounted on the platform  12 . The umbilical cords  18 ,  20  supply power and a communication link to the launch vehicle  22 . Additional umbilical cords are typically provided, for example an air conditioning umbilical. The umbilical mast  16  thus provides a means by which electrical and air conditioning umbilicals can be routed to the booster. These umbilicals provide control of the vehicle until lift off and cooling for the booster and payload electronics. The mast  16  is hollow to provide a protective channel for the umbilical cords and is made from a heavy material that can withstand a launch environment, for example steel. Aluminum can be used if the mast is to be a disposable mast. Typically the umbilical mast  16  is unique for the booster configuration being launched and as such may be changed after a launch for a different type of vehicle. An easy method of removal and replacement is therefore required. This could take the form of bolts passed through holes in an outwardly extending flange at the foot of the mast  16  and into threaded anchor sleeves secured in the mounting platform  12 . The mast typically comprises a tube having a circular or rectangular cross section. 
     FIG. 3 is an end view of the launch pad  10 , showing a blast deflector  24  which directs the exhaust gases from the launch vehicle  22  along the ducts  14 . 
     FIG. 4 is a side view of the launch pad  10  showing more clearly the power supply umbilical cord  18  and the communication and control umbilical cord  20  connected to the launch vehicle  22  from the mast  16 . 
     As is clearly shown in FIGS. 2 to  4 , the launch pad  10  has a modular construction which includes a frame  26  and a set of concrete panels which form building units  28 . This is also illustrated in FIG. 5 which shows a plan view of the launch pad  10  with its modularly constructed launch vehicle mounting platform  12  and ducts  14 . The platform  12  has a central exhaust gas opening  30 . The deflector  24  is visible through the exhaust gas opening  30 . The frame  26 , building units  28  and the manner of construction of the launch pad  10  will now be described in greater detail. 
     FIG. 6 illustrates a typical building unit which in this embodiment is a rectangular building unit  32 . The building unit  32  includes a mesh of longitudinally extending reinforcement bars  34  and transversely extending reinforcement bars  36  to form a rectangular skeleton. The bars  34 ,  36  typically comprise 1 inch or 2 inch diameter rebars. The choice of bar diameter depends on the forces that the pad  10  has to withstand. Clearly the bars  34 ,  36  are not limited to rebars. They could be made of any suitable material, for example rods made from a spun carbon material. 
     What makes the launch pad  10  unique is inter alia its modular construction and the manner in which the building units  28  are connected to the frame  26  and to each other. The blast created by the launch vehicle would exert excessive forces on any protruding bolts or other connectors extending into the interior of the launch pad  10  from the surfaces of the units. For this reason a system is used comprising internally threaded sleeves embedded in the units allowing the units to be bolted together using suitable brackets as described below. The internally threaded sleeves  38  are welded to a peripheral frame extending along the periphery of the skeleton as is discussed in greater detail below. The bars  34 ,  36  are connected near their ends to the sleeves  38  by means of pieces of wire  40 , the wire connections providing the structure with added support. 
     Clearly, the bars  34 ,  36  cannot cross one another centrally within the slab  42 . They are therefore laterally spaced from each other as shown in FIG.  7 . The transversely extending bars  36  are evenly spaced along virtually the entire length of the unit  32 . Thus not only the longitudinally extending bars  34 , but also the outermost transverse bars  36  are connected to the sleeves  38  extending along the lateral sides of the skeleton as illustrated in FIG.  7 . 
     Referring again to FIG. 6, the skeleton is embedded in a concrete slab  42  which is in turn embraced by the peripherally extending frame  44 . The frame  44  takes the form of U-shaped channel sections  46  made of one inch thick steel. The channel sections are connected to one another so that the legs  48  of the U-shaped channel sections  46  are directed inwardly to embrace the major surfaces  50  of the slab  42  along the edges of the slab  42 . As is shown in FIG. 6, the channel sections  46  are partially embedded in the concrete slab  42  so that the outer surfaces of the legs  48  lie flush with the major surfaces  50  of the slab  42  thereby providing a building unit having opposed smooth major faces  52 . It will be appreciated that the invention is not limited to concrete but could include any suitable material having the requisite strength and heat resistance, for example a carbon phenolic material. The embodiments illustrated in FIGS. 6 and 7 are substantially identical, save for the differences set out below, and are accordingly both depicted by reference numeral  32 . The sleeves  38  may extend between the outer surfaces of the legs  48  as illustrated in FIG. 6 or only between the inner surfaces of the legs  48  as illustrated in FIG.  7 . In either event, the sleeves  38  are welded to the legs  48  of the U-shaped channel sections  46 . Holes must be provided in at least one of the legs  48  to provide access to the threaded channels defined by the sleeves  38 . As will become clear from the description of the construction of the launch pad  10 , it is not essential that access be provided to the threaded channels of the sleeves  38  from both sides of the building unit  32 . Thus, holes need only be provided in one of the two legs  48  of the U-shaped channel sections  46 . However, for ease of construction and greater versatility, the two faces of the building unit are typically identical. In order to keep launch debris out of the threads of the sleeves and to protect the threads from high temperatures any openings are sealed after construction with a sealer. This could, for example, be a ceramic material such as the material known in the trade under the tradename MARTITE® or a high temperature rubber compound such as the compounds known in the trade as RTV-102 and Dynatherm 300. This also reduces turbulence of the launch vehicle exhaust gases by providing the structure with a smooth surface. 
     The above embodiment of the building unit  32  is one foot wide. The longitudinally and transversely extending reinforcement bars  34 ,  36  take the form of two inch rebar. The sleeves comprise internally threaded steel pipes having an outer diameter of two inches and an inner diameter of one inch. Typically all sides of the U-shaped channel sections  46  have equal dimensions, the legs  48  being 1 foot long and the back  54  being 1 foot wide. Thus the units  32  have a thickness of 1 foot. The concrete is designed to withstand a pressure of 3000 psi. The frame  26  and the construction of the launch pad  10  will now be described. 
     FIG. 8 illustrates the basic frame for the launch pad  10 , the frame of this embodiment being indicated generally by reference numeral  56 . The frame  56  is mounted on a concrete slab  58  which is cast on site. The slab  58  may be between  6  and 8 inches in thickness or, for greater safety, as thick as one foot. The frame  56  consists of a pair of longitudinally extending T-bars  60 . The arms  62 ,  64  of the T abut the slab  58  and are secured to the slab  58  by means of 2 inch bolts  66  (FIG. 9) passed through holes in the outer arms  62 . The body of the T forms an upwardly extending web  68  which serves as a support for vertically extending T-bars  70  of the frame  56 . As is illustrated in FIG. 10, the bolts  66  are secured in anchor sleeves  72  embedded in the slab  58 . The vertically extending T-bars  70  are each provided with a slot  74  at the lower end of the body  76  of the T in order to accommodate the web  68 . This is clearly illustrated in FIG. 11 which shows bolts  78  which are passed through complimentary holes  80  in the web  68  and through holes  82  in the arms  84  of the T-bar  70 . The bolts  78  are secured by engaging aligned sleeves (not shown) in the building units, as will become clearer hereinafter. The webs  68  of the T-bars  70  are 8 inches in length while the combined length of the arms  84  is 16 inches. 
     The longitudinally extending T-bars  60  are laterally spaced from each other by transversely extending ribs in the form of V-shaped angle irons  86  (FIGS.  8  and  11 ). The arms of the V are each 1 foot in length, have a thickness of 1 inch and are welded together at the vertex. The angle irons  86  act as braces for the T-bars  60 , providing the frame  56  with greater support. The angle irons  86  also serve as lower terminations for the blast deflector (not shown) as will be described in greater detail below. 
     Further strengthening ribs  88  (FIGS. 8 and 9) having a triangular cross-sectional profile connect the ends  90  of the two longitudinally extending T-bars  60  to one another. Another set of ribs  88  is provided at the mid-point along the T-bars  60  between the end points  90  and the angle irons  86 . Each rib  88  is formed in two sections  92 ,  94 , more clearly illustrated in FIG.  9 . The inner ends of the sections  92 ,  94  are welded to longitudinally extending bars  96 . The bars  96  are connected to one another by means of bolts  98  passed through complimentary aligned holes  100 ,  102  in the sections  92 ,  94 , respectively and secured by means of nuts  104 . The bolts  98  and nuts  104  and other exposed metal objects are covered with a protective coating, for example with the ceramic material known under the trade name MARTITE® or with a high temperature rubber compound such as the compounds known in the trade as RTV-102 and Dynatherm 300. To lessen the effects of turbulence, all coatings are ramped toward the expected flow of exhaust gases. This is illustrated in FIG. 12 in which the coating is depicted by reference numeral  105 . 
     FIG. 13 shows a sectional end view of a rib  88  and a longitudinally extending T-bar  60 . The base  106  of the rib  88  is typically 12 inches wide, the vertical height of the rib being 6 inches. FIG. 14 shows the rib  88  and T-bar  60  in plan view, clearly illustrating the weld joint  108  between the rib  88  and the bar  60 . The weld  108  is typically of the order of one inch in thickness. Once assembled, the frame  66  includes the horizontally extending bars, rods and angle irons  60 ,  86 ,  88  and  96 , four pairs of vertically extending T-bars  70  and two pairs of vertically extending elongate comer plates  110 . This is illustrated in FIG. 8. A side view of the frame  56  is also shown in FIG.  15 . 
     As is shown in FIG. 8, a launch mount base ring  112  is bolted to the slab  58  between the longitudinally extending T-bars  60  and the angle irons  86 . The base ring  112  will be described in greater detail below. 
     Once the frame  56  has been erected, the building units  28  are placed in position by means of regular cranes as illustrated in FIG.  16 . In order to erect the side walls of the pad  10 , rectangular building units  32  are placed in position so as to abut the longitudinally extending T-bars  60  along inner surfaces of the arms  64  and the webs  68 . The units  32  also abut the vertically extending T-bars  70  along the inner surfaces of the arms  84  and bodies  76 . The outermost building units  32  further abut inner surfaces of the vertically extending end plates  110 . Referring to FIGS. 17 and 18, the building units  10  are secured to the vertically extending T-bars  70  by means of bolts  114 . The bolts  114  also pass through horizontally extending connector plates  116  having a width of 2 feet and a thickness of 1 inch. As will become clearer hereinafter, the plates  116  serve to connect the vertically extending building units  118 , forming the side walls, to the horizontally extending building units  120  (FIG. 16) which act as covers for the ducts  14 . 
     The connection of the units  32  to the various T-bars and plates is accomplished by means of bolts passed through holes in the frame  56  and into the sleeves  38  of the units  32 . For instance, as was mentioned with respect to FIG. 11, the bolts  78  pass into the threaded sleeves of the vertical building units  118 . The lower ends of the units  118  are further connected to the webs  68  of the longitudinally extending T-bars  60  by means of bolts (not shown) passed through holes  121  (FIG. 11) in the webs  68 . 
     A more detailed side view of the connection of the horizontally extending building units (not shown) to the vertically extending units  118  is shown in FIG. 19. A vertically extending T-bar  70  is bolted to the connector plates  116  by means of the uppermost pair of the bolts  114 . Vertically extending units  118  are bolted to both the T-bar  70  and the plates  116  as described above. The plates  116  are in turn welded to the metal frames of the horizontally extending building units. A horizontally extending T-beam  122  is thereafter placed between the units  120  with the central web  124  of the T-beam  122  extending between the ends of the units  120 . The T-beam is provided with holes  126  extending through its arms  128 . This permits the T-beam  122  to be bolted to the units  120  by means of bolts (not shown) passed through the holes  126  into aligned sleeves of the units. It will be appreciated that the side view illustrated in FIG. 19 shows one of the short outer T-bars  70  which are indicated by reference numeral  130  in FIG.  16 . The long inner T-bars are not provided with connector plates but are instead connected to angle irons as is described below. 
     FIG. 20 shows a plan view of the launch pad  10  in a partially assembled state showing the vertically extending building units  118  secured to the frame  56 . The upper edges  132  of the units  118  act as resting surfaces for the ends of the horizontally extending building units (not shown in FIG.  20 ). This is best seen in FIG.  21 . When the horizontally extending unit  120  is placed on top of the vertically extending unit  118  the lower leg  134  of the unit frame  44  of the unit  120 , abuts the back  136  of the frame  44  of the unit  118 . The connector plate  116  is bolted to the units  120  and  118  by passing bolts  114  through holes in the plate  116 , and into the threaded sleeves  137 . The plate  116  is, in turn, welded to the back  138  of the unit  120 . In the embodiment illustrated in FIG. 21 the sleeve  137  in the unit  118  extends between the inner walls of the frame  44  while the bore which provides access to the threaded channel of the sleeve  137  passes through both legs of the U-shaped channel section  139 . 
     FIG. 22 shows substantially the same picture as that in FIG. 21, except that the sleeve extends through the outer leg of the channel section as well as through the plate  116 . In this embodiment the plate,  116  is secured to the unit  118  at the time of manufacture. Once the launch pad  10  is assembled, the plate  116  is welded to the unit  120 . It will be appreciated that in the embodiment illustrated in FIG. 21 the plate  116  could first be welded to the unit  120  before placing it on top of the unit  118  and bolting it thereto. The embodiment illustrated in FIG. 22 further differs insofar as a bore extends into the threaded channel of the sleeve through the outer leg of the frame only. Since the sleeves  140  perform no connector function in the horizontal units  120 , they can instead be replaced with 2 inch steel rods welded to the frames of the units  120 . 
     Once the horizontally extending units  120  have been secured to define the ducts  14  as illustrated in FIGS. 23 and 24, the launch vehicle mounting platform  12  has to be assembled. The mounting platform  12  comprises a pair of opposed building units  141  lying in parallel vertical planes. The units  141  have a rectangular shape and are identical in construction to the units  118  and  120 . Triangular building units  142  are secured to the units  141  on either side of the units  141 . The triangular units  142  are similar in construction to the rectangular units described with reference to FIG. 6 except that the shape differs. Each triangle  142  is secured to a rectangular unit  141  by means of one of the long vertically extending T-bars  144 . Along its base, the triangle  142  is secured to a vertically extending unit  118  as illustrated in FIG.  24 . The connection to the unit  118  is achieved by means of the connector plate  116 . Once the triangular building units  142  are in place, a pair of slanted building units  146  are secured in place on top of the units  142 . The building units  146  are provided with longitudinally extending bevelled edges to permit the units  146  to be secured in a slanted manner as described below. 
     The lower slanted edge of each unit  146  is connected to the adjacent horizontal unit  148  by means of an angle iron  150  having spaced holes along both of its arms. Bolts are passed through the holes in the angle iron  150  and into aligned sleeves embedded in the adjacent unit  148  and in the bevelled edge  152  of the unit  146 . Suitably shaped 1 inch thick steel connector plates  154  are bolted to the slanted sides  156  of the triangular building units  142 . The plates  154  are then bolted or welded to the lateral edges  158  of the units  146 . Clearly if the plates  154  are to be bolted to the edges  158 , threaded sleeves have to be cast into the units  146  so as to extend laterally into the units  146  from the edges  158 . This differs from the orientation of the sleeves  38  in the FIG. 6 embodiment. 
     The upper end  160  of the unit  146  is connected to a set of three brackets as illustrated in FIGS. 24 and 25. A V-shaped angle iron  162  is bolted by means of bolts  164  to the building unit  146 . The bolts  164  are received in sleeves  166  secured in the unit  146 . The free leg  168  of the angle iron  162  is provided with a plurality of spaced apart holes and forms a support surface for the second bracket  170  and third bracket  172 . The bracket  170  takes the form of an angle iron, the legs of which have spaced apart, longitudinally extending holes passing therethrough. The one leg  173  of the bracket  170  is attached to the free leg  168  of the angle iron  162  to abut the outer face of the free leg  168 . The other leg  174  of the bracket  170  extends outwardly to provide a horizontal support surface as shown in FIG.  25 . The third bracket  172  comprises an elongate plate the ends of which are bent to extend perpendicularly outwardly as shown in FIG.  24 . The bracket  172  is secured to the inner surface of the leg  168  so that the outwardly bent ends are receivable between the vertically extending T-bars  144  as shown in FIGS. 26 and 27. Bolts  176  and nuts  178  secure the three brackets  162 ,  170  and  172  to one another. It is thus clear that the bracket  162  serves as a support for the other two brackets. The bracket  170  then provides a connecting formation for the platform plates  180  illustrated in FIG.  27  and described in greater detail below. The bent ends of the bracket  172  provide connecting formations for connection to the T-bars  144 . Referring to FIGS. 27 and 28, each laterally located, slanted connector plate  154  can be secured at its upper and lower ends externally to a T-bar  144  and a connector plate  116 . The upper edge of the plate  154  is connected to the edge  158  of the slanted unit  146 . The lower edge of the plate  154  is bolted to the triangular unit  142 . In the embodiments illustrated in FIGS. 27 and 28 the connections to the edges  158  take the form of a weld. 
     Referring again to FIG. 27, the platform plates  180  comprise square building units having a semi-circular cutaway portion to define an exhaust gas opening in the form of a central hole  182  when the four plates  180  are connected. As shown in FIG. 27, the four plates  180  are secured to one another along their opposed edges by means of T-bars  184 . The body  186  of the T forms a web intermediate the opposed edges of the plates  180 . Holes are provided in the arms  188  of the T, thereby allowing the T to be bolted to two adjacent plates  180 . The transversely extending sides of the plates  180  are secured to the brackets  170  by means of bolts passed upwardly through the holes in the legs  174  into threaded sleeves embedded in the plates  180 . 
     The longitudinally extending sides are connected to angle irons  189  bolted to the upper ends of the units  141  as shown in FIG.  27 . The angle irons  189  have arms which are 1 foot in length. FIG. 29 shows a plate  180  bolted to an angle iron  189 . Bolts  190  (one shown) pass through the horizontal leg  191  into the plate  180 . The plates  180  differ from the building units described so far in that a second U-shaped channel  192  is embedded in the concrete of the plate  180 . Internally threaded sleeves  194  are also embedded in the concrete in a similar manner as was described with respect to FIG. 6 for the sleeves  38 . In the plate  180  illustrated in FIG. 29 the arms  196  of the channel  192  are directed outwardly. Clearly threaded sleeves are not required along the outer free edges of the plates  180 . However, in order to accommodate the T-bars  184  between the plates  180 , sleeves are embedded along the edges opposing the edges of adjacent plates  180 . These sleeves are indicated in FIG. 29 by reference numeral  198 . The sleeves  194 ,  198  also serve as connecting formations for the internally extending reinforcement bars (not shown). The bars are connected to the sleeves  194 ,  198  by means of pieces or wire as was described with reference to FIGS. 6 and 7. Aside from the shape of the plate  180 , the addition of the channel  192  and the positioning of the sleeves, the construction of the plates  180  is the same as that described for the building unit  32  in FIG.  6 . 
     Referring to FIG. 30, it is clear that prior to the plates  180  being secured in place, the blast deflectors  24  and the launch mount base ring  112  have to be secured in place. Referring to FIGS. 31 and 32, the base ring  112  comprises an annular structure  200  provided with  12  circumferentially extending holes  202  extending therethrough. Four cup-like formations  204  are secured to the upper surface of the annular structure  200 , for example by welding. The annular structure has a thickness of four inches, an outer diameter of 96 inches and an inner diameter of 60 inches. The cup-like formations  204  are 12 inches in height, have an outer diameter of 16 inches and an inner diameter of  12  inches. The cup-like formations  204  serve to accommodate 12 inch diameter hollow pillars  206  having an inner diameter of six inches as illustrated in FIGS. 33 and 34. In this embodiment, the pillars  206  have a length of 197 inches. The pillars  206  can be inserted into the formations  204  only once the blast deflectors  24  are in place or the deflectors  24  can be placed over the pillars  206  once the pillars  206  are secured to the formations  204 . 
     The blast deflectors  24  are more clearly illustrated in FIGS. 35 to  37 . For purposes of portability, each deflector  24  consists of two plates  208  mounted next to each other. The plates  208  can be connected to each other, for example by welding. The plates  208  are made of two inch thick steel and have a concave profile. The plates  208  of the two deflectors  24  join at their upper edges to form a vertex  210  as is shown in greater detail in FIG.  38 . The one deflector  212  is slightly shorter than the other deflector  214 , the edge of the deflector  212  abutting the lower surface of the deflector  214 . Both deflectors are coated with a ceramic layer  216  known in the trade under the tradename MARTITE® or with a high temperature rubber compound such as those known in the trade as RTV-102 and Dynatherm 300. The plates  208  are welded to one another at the various junctions and are supported by means of props  218  mounted on bases  220 . Lateral sides walls  221  can be secured to the deflectors  24  as shown in FIG.  35 . This reduces pressure build up under the deflectors  24  which could cause warping and possible damage to the deflector plates  208 . The walls  221  are attached using bolts received in complementary holes drilled into the side edges of the deflectors  24 . 
     As mentioned with reference to FIG. 1, the lower extremities of the deflectors  24  terminate in the form of the angle irons  86 . This is best illustrated in FIG. 39 where a deflector plate  208  is shown abutting the lower extension portion  222  of the angle iron  86 . The lower extension portion  222  is welded to the lower leg of the angle iron  86  and has a thickness of 1 inch and a width of 1 foot. The upper surface  224  of the plate  208  lies flush with the upper surface of the angled arm  226  of the angle iron  86 . Bolts  228  pass through the plate  208  and into the lower extension portion  222  thereby securing the lower extremity of the plate  208  to the angle iron  86 . The bolts  228  are typically covered with a protective coating of MARTITE® or a high temperature rubber compound such as RTV-102 or Dynatherm 300 in a manner as was described with reference to FIG. 12 for bolts  98  and nuts  104 . 
     Instead of, or in addition to, coating the plates  208  with MARTITE® or a rubber compound, water may be sprayed onto the outer surfaces of the deflectors  24  during the launching of a launch vehicle as is illustrated in FIG.  40 . Water is supplied from one or more fire hydrants  229  mounted on inner surfaces of the launch vehicle mounting platform  12 . The fire hydrants  229  are remotely operated just prior to lift off. The water spray on the blast deflectors  24  cools the metal and prevents damage to the deflectors  24 . Water spray also tends to deaden the blast lowering the sound level that reaches the booster or payload. 
     The plates  208  are provided with a hole each to act as a passageway for the pillars  206 . Once the deflectors  24  are mounted in place, the pillars  206  are inserted into the formations  204  to protrude through the deflectors  24  as shown in FIGS. 35 to  37 . FIG. 41 shows an end view of the launch pad  10  showing one of the ducts  14  and the deflector  24  and pillars  206  viewed through the duct  14 . The pad  10  has a width of 16 feet between the outer surfaces of its lateral walls and a height of 17.08 feet. The mounting platform  12  has a width at the widest point of 22 feet and the duct height is 18.08 feet. 
     FIG. 42 illustrates a side view of the launch mount with its base ring  112 , the pillars  206  and a launch ring  230 . Referring to FIGS. 43 and 44, the launch ring  230  is similar to the base ring  112 . It includes an annular structure  232  consisting of four inch thick steel and having an outer diameter of 96 inches and an inner diameter of 60 inches. Clearly no bolt holes are required in the annular formation  232 , however four threaded holes  234  are provided to accommodate four alignment balls  236 . The balls  236  are each provided with a threaded shaft (not shown) which is complimentarily engageable with a holes  234 . The threaded shafts allow the balls  236  to be raised or lowered thus allowing the launch vehicle, which sits on the balls  236 , to be leveled. This is essential for the inertial guidance system of the launch vehicle to operate properly. As is described in greater detail below, the launch vehicle can instead be mounted using explosive bolts. 
     Four cup-like formations  238  are secured to the lower surface of the annular formation  232 , for example by welding. The formations  238  have an outer diameter of 16 inches, an inner diameter of 12 inches and a height of 12 inches. The cup-like formations  238  are thus sized to received the pillars  206 . This allows for easy replacement of the launch ring to accommodate different-sized launch vehicles. FIGS. 45 to  47  show different embodiments of the launch ring. The launch ring  240  illustrated in FIG. 45 has a 52 inch inner diameter and three alignment balls  242 . The launch ring  244  of FIG. 46 has four alignment balls  246  and an inner diameter of 52 inches. The launch ring  248  illustrated in FIG. 47 has four alignment balls  250  but an inner diameter of only 48 inches. 
     The versatility of the launch mount can be further enhanced by replacing the upper launch ring with an adapter  252  as illustrated in FIGS. 48 to  50 . The adapter comprises a rectangular frame  254  to which are attached four feet  256 . The feet  256  are stabilized by means of webs  258  extending between outer walls  260  of the feet  256 . Each foot  256  includes two outer walls  260  aligned perpendicularly to one another. Spaced from the outer walls  260  are a pair of inner walls  262  thereby providing two channels  264  at right angles to one another. The walls  260 ,  262  are mounted on a base plate  266  which is welded onto a pillar  206 . Four arms  268  are pivotally mounted in the channels  264 . Each arm  268  is provided with a pair of downwardly extending bars  269  received in the channels  264  as illustrated in FIG. 49, and pivotable about pivotal axes in the form of bolts  270 . Each arm  268  extends upwardly in the form of a tapered frame structure which includes a pair of outer ribs  272  and a pair of inner ribs  274 . The ribs  272 ,  274  are joined at their upper extremities. The inner ribs  274  define a channel  276  between them. A pedestal in the form of a T-shaped support formation  278  is pivotally secured in each channel  276  by means of a downwardly extending plate  279  received in the channel  276 . The pedestal  278  is pivotable about a bolt  280 . The base  282  of the pedestal  278  provides a flat support surface for a launch vehicle. Referring to FIG. 50 each arm  268  is pivotable between one of three positions by virtue of retaining bolts  290  (FIG. 49) associated with the bars  269 . Each bolt  290  is engageable with one of three holes  292  extending through the walls  260 ,  262 . A hole  294  extending through the lower extremity of the bar  268  is alignable with any one of the holes  292  to receive the bolt  290 . In order to keep the bases  282  horizontal irrespective of the positions of the arms  268  a corresponding adjustment of the pedestals  278  is necessary whenever the arms  268  are adjusted. The pedestals  278  are adjustable using a method similar to the one described above. For each pedestal  278  a retaining bolt  296  is passed through one of three holes  298  to engage an outer surface of the plate  279 . As with all other components that are to be re-used, the pedestals  278  are coated with a heat resistant material, for example MARTITE®, RTV-102 or Dynatherm 300. 
     It will be appreciated that adjustment of any of the arms  268  requires a corresponding adjustment of the other arms  268  to ensure that the heights of the bases  282  remain equal. Furthermore in this, as well as in the launch ring embodiment, the compression factor of the pillars  206  has to remain substantially constant to maintain a horizontal launch platform. As is shown in FIG. 51 the pedestals  278  may be provided with alignment balls  299  in the same way as was described above for the launch rings. The balls  299  have threaded adjustment shafts  300  received in complementary bores in the pedestals  278 . This allows the launch vehicle  301  to be leveled. FIG. 52 shows another embodiment. Explosive bolts  302  secure the launch vehicle  303  to the pedestals  278 . It will be appreciated that the bores in the pedestals  278  will be appropriately sized to accommodate the shafts  300  or bolts  302 . The bolts  302  fire at engine start of the launch vehicle  303 . Alignment and leveling of the launch vehicle  303  is accomplished by bolt adjustment and shimming the bottom of the booster using shims  304 . 
     The launch pads  10  described thus far all included a pair of laterally extending cylindrical ducts  14 . It will be appreciated that a wide variety of different launch pads can be developed using the principles discussed above. For instance, the launch pads could have one or more than two exhaust gas ducts. One embodiment is illustrated in FIG.  53  and shows a launch pad  305  having ducts  306  extending laterally outwardly and flaring outwardly in funnel-like fashion. 
     FIG. 54 shows a similar embodiment to the one illustrated in FIG. 53 except that the launch pad  307  in this embodiment has longitudinally extending vertical walls  308  dividing each of the ducts  309  in half, thereby effectively creating a pair of ducts extending in the two directions. 
     FIGS. 55 and 56 show a launch pad  310  having a pair of flared ducts  312  extending from only one side of the mounting platform  314 . Clearly in such an embodiment, where ducts extend only to one side, only a single deflector  316  is required as illustrated in FIG.  55 . The deflector  316  differs from the deflector previously described insofar as the deflector extends all the way to the exhaust opening  318 . A further embodiment of a launch pad having a duct extending only to one side is illustrated in FIGS. 57 and 58. The launch pad  320  of this embodiment shows a much larger duct  322  having parallel sides and a height corresponding to that of the launch vehicle mounting platform  324 . Again the deflector  326  extends all the way up to the exhaust gas opening  328  as illustrated in FIG.  58 .