Abstract:
A Submarine Horizontal Launch TACTOM Capsule (SHLTC) provides the capability for launching a Tactical Tomahawk (TACTOM) cruise missile from a horizontal torpedo tube on a submarine. The SHLTC completely encapsulates the TACTOM missile in the torpedo tube and is ejected from the torpedo tube with the TACTOM missile during launch. The SHLTC contains the TACTOM missile in a closure assembly to protect the TACTOM missile from damage. Following safe exit from the submarine, thrust from the rocket motor allows the TACTOM missile to break through a forward tearing shell of the SHLTC. The TACTOM missile and SHLTC completely de-couple and the SHLTC safely sinks away from the submarine and missile. The TACTOM missile continues up to broach the surface and transition to cruise mode.

Description:
STATEMENT OF GOVERNMENT INTEREST 
     The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor. 
    
    
     BACKGROUND OF THE INVENTION 
     (1) Field of the Invention 
     The present invention relates generally to a means for launching a missile from an undersea craft. More particularly, this invention relates to a capsule that provides the capability for reliably launching a Tomahawk cruise missile from the torpedo tube of a submarine. 
     (2) Description of the Prior Art 
     Currently, an operational cruise missile (Tomahawk Block III) is capable of being launched from a torpedo tube of a submarine is retained in a slotted capsule. The slotted capsule for this missile, referred to as the submarine torpedo tube launched (TTL) cruise missile, provides protection for the missile during loading, handling, and shipping evolutions. The slotted capsule exposes the missile to the flow of water from the system that ejects the missile from the torpedo tube. The capsule remains in the torpedo tube during and after launch of the missile, and consequently, the missile is exposed to damaging environments during exit from the torpedo tube and as it transitions through ambient water to near vertical orientation and ignition of a rocket motor on the missile. 
     The cruise missile known as the Tactical Tomahawk (TACTOM) is the next generation of the Tomahawk Cruise missile. Currently, TACTOM is being developed for vertical launch systems (VLS) for surface ships and Capsule Launch Systems (CLS) for submarines, only. The submarine CLS launch system protects the TACTOM from operational environments by completely encapsulating the missile. CLS TACTOM is ejected from the submarine/capsule via a gas generator, and capsule seals protect the TACTOM from ejection pressures. Modifications of current requirements and design of TACTOM have been excluded by an operational requirements document that would allow compatibility with environments for launch of TACTOM in torpedo tubes of current and future submarines. The TACTOM program is currently ongoing, with a critical design review (CDR) having been completed. It has been estimated by the design agent for TACTOM that the costs associated with changing the design/requirements following the CDR stage of the TACTOM program would be unacceptable given today&#39;s budget constraints. These changes would also cause significant delays in meeting the date when TACTOM is introduced in the Fleet. 
     Thus, in accordance with this inventive concept, a need has been recognized in the state of the art for an ejectable encapsulating structure, or capsule to launch missiles from underwater tubes including horizontally orientated torpedo tubes within current design, development and production schedules for TACTOM. 
     SUMMARY OF THE INVENTION 
     The first object of the invention is to provide the capability of launching Tactical Tomahawk (TACTOM) cruise missiles from horizontal torpedo tubes of submarines. 
     Another object is to provide launch environment protection to a TACTOM missile during pre-launch and launch stages in a horizontal torpedo tube and during ejection from the torpedo tube. 
     Another object is to provide a Submarine Horizontal Launch TACTOM Capsule (SHLTC) completely encapsulating a TACTOM missile during pre-launch and launch stages in a horizontal torpedo tube and during ejection from the torpedo tube to protect the TACTOM missile from damage. 
     Another object is to provide a SHLTC completely encapsulating a TACTOM missile to assure an intact and operational TACTOM missile as its rocket motor ignites at a safe separation distance from the submarine at depths of the torpedo tube. 
     Another object of the invention is to provide a SHLTC to launch missiles from horizontal torpedo tubes without affecting the current design, development and production schedules of the TACTOM. 
     Another object of the invention is to completely de-couple the TACTOM and SHLTC from each other as a rocket motor ignites to allow the SHLTC to sink away from the submarine and the TACTOM to continue towards the surface, broach the surface of the water and successfully transition to cruise. 
     These and other objects of the invention will become more readily apparent from the ensuing specification when taken in conjunction with the appended claims. 
     Accordingly, the present invention is a submarine horizontal launch TACTOM capsule including an aft closure assembly, capsule closure assembly, and forward closure assembly to encapsulate a TACTOM cruise missile during pre-launch and launch and provide the capability of launching a TACTOM cruise missile from torpedo tubes of submarines. The aft closure includes a back plate having components for pressurization vent control (PVC), the capsule barrel assembly includes longitudinal strips, and the forward closure assembly has a tearing shell to protect the TACTOM missile from harsh environmental abuses, such as torpedo tube flooding, hydraulic (water) impulses created during ejection of the TACTOM missile from a torpedo tube, damage caused by impact with surfaces and the mouth of the torpedo tube, damage causes by ambient shocks, equalization pressures inside the torpedo tube and the capsule, etc. Protection of the TACTOM missile from these abuses must be provided for by the SHLTC since the missile was not designed to be subjected to such abuses and survive. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A more complete understanding of the invention and many of the attendant advantages thereto will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein like reference numerals refer to like parts and wherein: 
     FIG. 1 is a cross-sectional schematic view of the Submarine Horizontal Launch TACTOM capsule (SHLTC) of this invention encapsulating a Tactical Tomahawk (TACTOM) cruise missile in the torpedo tube of a submarine to assure safe launching therefrom; 
     FIG. 2 is a schematic view of a back plate portion of an aft closure assembly showing components that provide some of the features of this invention; and 
     FIG. 3 is a schematic front view of the non-flexible metallic multi-leaf barrier of the forward closure assembly that will allow for uninhibited egress of the TACTOM missile from the SHLTC following ignition of the rocket motor. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIG. 1 of the drawings, a TACTOM missile  7  is shown in a submarine horizontal launch TACTOM capsule (SHLTC)  10  prior to being launched from horizontally oriented torpedo tube  8  of submarine  9 . SHLTC  10  protects TACTOM missile  7  throughout its launch sequence in torpedo tube  8  and part of the launch sequence in ambient water  50 . 
     SHLTC  10  and TACTOM  7  are ejected from torpedo tube  8  and submarine  9  as a combined unit, a SHLTC All-Up-Round (AUR) hereinafter referred to as SHLTC AUR  15 . SHLTC AUR  15  is ejected from torpedo tube  8  by impulses  8   a  of pressurized water fed through port  8   b  of torpedo tube  8  from submarine  9 . The outer diameter of SHLTC  10  of SHLTC AUR  15  is sized to permit sliding axial displacement of SHLTC AUR  15  in torpedo tube  8  by impulses  8   a  of pressurized water to a position where it has been ejected outside of submarine  9 . Then, after the ejected SHLTC AUR  1 s has continued to travel, or glide away from submarine  9  to what is known as a safe separation distance, rocket motor  7   a , adjacent to shroud  7   c  and connected to tapered tail cone  7   c , is ignited. After ignition, burning propulsion gases from rocket motor  7   a propel TACTOM missile  7  from SHTLC  10 , to and through the surface of ambient water  50 , and on towards a target. 
     SHLTC  10  has three major assemblies sized to contain TACTOM missile  7 . These assemblies, including an aft closure assembly  20 , a capsule barrel assembly  30 , and a forward closure assembly  40 , completely encapsulate TACTOM missile  7  during the ejection sequence. Consequently, SHLTC  10  is able to protect TACTOM missile  7  from harsh environmental abuses, such as torpedo tube flooding, hydraulic (water) impulses Ba created during ejection of TACTOM missile  7  from tube  8 , damage caused by impact with surfaces and the mouth of torpedo tube  8 , damage caused by ambient shocks, equalization pressures inside tube  8  and SHLTC  10 , etc. Protection of TACTOM missile  7  from these abuses must be provided for by SHLTC  10  as the missile was not designed to be subjected to such abuses and survive. 
     Referring also to FIG. 2, aft closure assembly  20  can be made of metal and includes a back plate portion  22  that houses all of the components for the pressurization vent control (PVC) system to allow internal pressurization of SHLTC  10  and TACTOM missile  7  prior to and during launch. This internal pressurization prevents leakage of water  50  into SHLTC  10  and TACTOM  7  during pre-launch and launch phases of TACTOM missile  7  while underwater, following SHLTC  10  separation. Appropriate amounts of pressurized gas may be fed to the interior of SHLTC  10  via pneumatic connector fitting  23  in back plate  22  that is connected via an umbilical hose (not shown) to a remotely located source of pressurized gas (not shown) to maintain an overpressure within SHLTC  10  as compared to the pressure in torpedo tube  8  and ambient water  50 . A pressure relief valve  24  extends through back plate  22  to vent inadvertent overpressures from SHLTC  10  and TACTOM  7 . Such overpressures might be created, for example, as submarine  9  ascends and approaches the surface at rates faster than recommended rates, or from a PVC system malfunction. 
     Back plate  22  is built substantially enough to bear the load of displacing SHLTC AUR  15  from torpedo tube  8  by impulses  8   a  of water, and includes electrical connector  25  for interfacing with appropriate umbilical harnesses of electrical power and control leads (not shown) to start rocket motor  7   a  and/or initiate and possibly modify the operational program for TACTOM missile  7 . In a preferred embodiment, load button  26  is included to allow loading of SHLTC AUR  15  into torpedo tube  8 . 
     A pressure inlet  27  extending through back plate  22  is coupled to a differential pressure transducer  27   a  mounted on the inner wall of back plate  22 . Pressure transducer  27   a  provides signals through electrical connector  25  that are representative of differential internal pressures between SHLTC AUR  15  and torpedo tube ambient water  50 . These internal pressures may be monitored in submarine  9  and automatically or manually compensated for via pneumatic connector fitting  23  and pressure relief valve  24 . 
     A plurality of disks  28  is provided in back plate  22  that rupture to exhaust, or vent amounts of propulsion gases from rocket motor  7   a  during its ignition. Rupture discs  28  cover ports  28   a  total about  50  square inches in area so as to adequately vent propulsion gasses when discs  28  are blown free of back plate  22  by built up pressure from propulsion gases. As a result, the build up of pressure from propulsion gases is reduced so that overpressure and possible damage of TACTOM missile  7  are prevented before it is powered out of SHLTC  10 . 
     Separation bolts  29  are connected to back plate  22  via bolt heads  29   a . Separation bolts  29  extend to and are connected to motor  7   a  of TACTOM missile  7  to releasably secure it in SHLTC  10 . When TACTOM missile  7  is ejected from torpedo tube  8  and then becomes launched from SHLTC  10  as rocket motor  7   a  is initiated a safe distance outside of submarine  9 , the thrust provided by burning propulsion gases from rocket motor  7   a  parts separation bolts  29  to free, or release TACTOM missile  7  from SHLTC  10 . Capsule barrel assembly  30  includes a composite barrel  31  made, for example, from an approximately 0.280 inch thick layer of fiberglass/epoxy resin composite material that is suitably connected in a sealed relationship to aft closure assembly  20 . A plurality of internal slide strips  32  made from a low friction material is provided in the inside of barrel  31  and extend longitudinally in barrel  30  in a spaced apart relationship with each other. Strips  32  lie adjacent to TACTOM missile  7  to assist in smooth decoupling and departure of TACTOM missile  7  from SHLTC  10  during ignition of rocket motor  7   a . The outer diameter of barrel  31  of SHLTC  10  is sized to permit sliding axial displacement of SHLTC AUR  15  in torpedo tube  8  by impulses  8   a  of pressurized water to a position where it has been ejected outside of submarine  9 . The inner separations of slide strips  32  on opposite inner sides of barrel  31  are such as to permit sliding axial displacement of TACTOM missile  7  within barrel  31  of SHLTC  10  by the thrust provided by propulsion gases from rocket motor  7   a  to a position outside of SHLTC  10 . Use of this composite material in barrel  31  provides cost effective flexibility in design since material and manufacturing costs associated with composite barrel  31  are significantly cheaper than a metallic barrel (stainless, aluminum, etc.) with virtually no increase in maintenance requirements. In addition, a weight savings of approximately 500 lbs results from using composite materials for capsule barrel assembly  30 . This savings in weight may allow for placement of additional ballast in the aft portion of barrel  31  and/or aft closure assembly  20 . This placement can produce a desirable distribution of mass for optimal dynamic characteristics during underwater launch of SHLTC AUR  15  as rocket motor  7   a  ignites. Annular seal  33  can be located around the inside of barrel  31  to prevent blow-by of propulsion gases from burning rocket motor  7   a.    
     Barrel  31  of capsule barrel assembly  30  might be made from stainless steel if other design constraints prevent utilization of composite materials. In either case capsule barrel assembly will be designed accordingly to provide sufficient structural integrity to withstand high impact shock environments while stowed in torpedo rooms, such as aboard SSN 688, SEAWOLF and VIRGINIA submarines to ensure that high safety requirements are met. 
     Forward closure assembly  40  has a conical shell portion  41  connected in a sealed relationship to capsule barrel assembly  30  via a rubber reinforced ring portion  42  to seal the interior of SHLTC  10  and TACTOM missile  7  from the ambient water  50 . Forward closure assembly  40  additionally has an interior portion  43  made from polyurethane molded to contiguously conform to the inside surface of conical shell portion  41  and the outside surface of the nose  7   d  of TACTOM missile  7  and fill the space between shell portion  41  and nose  7   d.    
     Referring also to FIG. 3, conical shell portion  41  of forward closure assembly  40  can be fabricated from a sheet of rigid aluminum having a thickness of about 0.063 inches, for example. Optionally, a corrosion resistant coating can be provided on the exterior surface of conical shell portion  41 . The non-flexible attributes of rigid conical shell portion  41  will eliminate bootstrapping environments that could arise, such as during pressurization of a TOMAHAWK (Block III) in an unvented torpedo tube  8 . (Pressure increases caused by flexible diaphragm expansion in a closed and flooded tube  8  during launch of a TOMAHAWK (Block III) can overpressure the Block III missile and rupture its flexible diaphragm prematurely.) 
     Eight grooves  45  are cut into rigid conical shell portion  41  through its apex  41   a  to its trailing region  41   b  adjacent to ring portion  42  and provide paths of least resistance for tearing under pressure into triangular sections  41   c . Interior portion  43  of forward closure assembly  40  is partitioned into wedge-shaped sections  46  with the separations between adjacent sections being located in line with and under grooves  45 . Conical shell portion  41  and ring portion  42  of forward closure assembly  40  withstand differential pressures caused by higher pressures (overpressures) inside of SHLTC  10  in the range of about 5 psi and higher pressures (overpressures) outside of SHLTC  10  in the range of about 100 psi. 
     Grooves  45  are about 0.03 inches deep to define the interconnected non-flexible metallic multi-leaf barrier of eight triangular sections  41   c . Grooves  45  are provided in conical shell portion  41  to rupture and tear along their lengths into triangular sections  41   c  as pressure builds up to levels that are in excess of 5 psi inside SHLTC  10  from TACTOM missile  7  forward movement following rocket motor  7   a  ignition. In addition to the rupturing and tearing along the lengths of grooves  45 , the TACTOM missile  7  egress peels eight triangular sections  41   c  outward and back from nose  7   d  of TACTOM missile  7  to allow uninhibited egress and exit of TACTOM missile  7  from SHLTC  10  by the thrust created by propulsion gases coming from burning rocket motor  7   a . This uninhibited egress and exit from SHLTC  10  by TACTOM missile  7  occurs outside of torpedo tube  8  at a safe separation distance from submarine  9 . 
     As mentioned above, SHLTC  10  is the mechanism to eject TACTOM missile  7  from torpedo tube  8  and launch it in water  50 . SHLTC  10  and TACTOM missile  7  are launched from torpedo tube  8  as a combined unit, SHLTC All-Up-Round (AUR)  15 . SHLTC AUR  15  slideably fits within torpedo tube  8  so that it may be ejected from torpedo tube  8  by impulses  8   a  of pressurized water fed to it from submarine  9 . No latches are needed to restrain SHLTC AUR  15  in torpedo tube  8 , since both SHLTC  10  and TACTOM missile  7  are ejected from tube  8  at launch. SHLTC AUR  15  has approximately 600 lbs of negative buoyancy in water  50  and after it is safely ejected from tube  8  of submarine  9 , forward closure assembly  40  and nose  7   d  of TACTOM missile  7  pitch upwards in water  50  due to the relationship of the center of buoyancy to the center of gravity of SHLTC AUR  15 . 
     Following the ejection of SHLTC AUR  15  from torpedo tube  8 , SHLTC AUR  15  travels a safe separation distance away from the hull of submarine  9 . Then, at the safe separation distance from submarine  9 , rocket motor  7   a  is ignited within SHLTC  10  at predetermined pitch angle/axial velocity conditions. SHLTC  10  houses pressurization vent control (PVC) components (as described previously) that are required for horizontal launch from torpedo tube  8  but were eliminated in the CLS TACTOM program. At ignition, thrust from rocket motor  7   a  pulls apart separation bolts  29  to release TACTOM missile  7  from aft closure assembly  20  and TACTOM missile  7  is propelled from SHLTC  10  to its designated target. SHLTC  10  then sinks safely clear of submarine  9 . Thus, SHLTC  10  encapsulates TACTOM missile  7  to overcome the design limitations of TACTOM missile  7  and allow horizontal launch of missile  7  without requiring changes in its current baseline design. 
     SHLTC  10  of this invention is a cost effective way to launch TACTOM missiles  7 , and other missiles from conventional torpedo tubes on submarines. SHLTC  10  can additionally be used in other launch scenarios, for example, in vertical or other orientations from different launch structures other than torpedo tubes. The complete encapsulation provided for by SHLTC  10  may help prevent aging and deterioration of components of the missile contained in it so that long-term reliability is enhanced. Thus, SHLTC  10  of this invention has flexibility in its design and applications to improve readiness for prolonged operations in a variety of different applications. SHLTC  10  in accordance with this invention gives tacticians and military personnel new and reliable options on land as well as on and below the surface of the water. 
     SHLTC  10  provides a way to launch TACTOM missile  7  from a torpedo tube without affecting current TACTOM design, development, and fleet introduction timeliness. SHLTC  10  completely encapsulates TACTOM missile  7  during pre-launch and launch operations in the torpedo tube, and will be ejected from the torpedo tube with TACTOM missile  7 . This procedure differs significantly from existing TTL Tomahawk missile launches where the slotted capsule remains in the torpedo tube and the missile is susceptible to damage from the damaging environments associated with launching such missiles from torpedo tubes. Following safe exit from the hull of a submarine and parameters for ignition of the rocket motor, TACTOM missile  7  is ejected from SHLTC  10  via its rocket motor at depths where torpedo tubes of a submarine are located. 
     The disclosed components and their arrangements as disclosed herein all contribute to the novel features of this invention. SHLTC  10  of this invention provides a reliable and cost-effective means to improve the capabilities of the Fleet. Therefore, SHLTC  10  as disclosed herein is not to be construed as limiting, but rather, is intended to be demonstrative of this inventive concept. 
     It will be understood that many additional changes in the details, materials, steps and arrangement of parts, which have been herein described and illustrated in order to explain the nature of the invention, may be made by those skilled in the art within the principle and scope of the invention as expressed in the appended claims.