Patent Publication Number: US-2009223404-A1

Title: Fixed deployed net for hit-to-kill vehicle

Description:
RELATED APPLICATIONS 
     This application is a divisional of prior U.S. patent application Ser. No. 10/384,804 filed Mar. 10, 2003, which claims the benefit of and priority to U.S. Provisional Application Ser. No. 60/406,828 filed Aug. 29, 2002, each of which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to improvements in hit-to-kill vehicles. 
     BACKGROUND OF THE INVENTION 
     Destroying missiles, aircraft, re-entry vehicles and other targets falls into three primary classifications: “hit-to-kill” vehicles, blast fragmentation warheads, and kinetic energy rod warheads. Blast fragmentation and kinetic energy rod warheads are kill enhancement devices that are carried along on the “hit-to-kill” vehicle. 
     “Hit-to-kill” vehicles are typically launched into a position proximate a re-entry vehicle or other target via a missile such as the NMD System, THAAD, SM3, Trident or MX missile. The kill vehicle is navigable and designed to directly strike the re-entry vehicle to render it inoperable. Countermeasures, however, can be used to avoid the “hit-to-kill” vehicle. Moreover, nuclear or biological warfare bomblets and chemical warfare submunition payloads are carried by some targets threats. If the nuclear payload or more then one of these bomblets or chemical submunition payloads can survive, they would cause heavy casualties even if the “hit-to-kill” vehicle accurately strikes the target. 
     Blast fragmentation type warheads are designed to be carried by existing missiles. Blast fragmentation type warheads, unlike “hit-to-kill” vehicles, are not navigable. Instead, when the missile carrier reaches a position close to an enemy missile or other target, a pre-made band of metal on the warhead is detonated and the pieces of metal are accelerated with high velocity and strike the target. The fragments, however, are not always effective at destroying the nuclear target and, again, fall out, radiation, biological bomblets and/or chemical submunition payloads survive and cause heavy casualties. Also, a blast fragmentation warhead requires a fuse detection device that must be very accurate. Those types of accuracies in outer space are very difficult to achieve. Other warheads concepts need to be developed. 
     The textbooks by the inventor hereof, R. Lloyd, “Conventional Warhead Systems Physics and Engineering Design,” Progress in Astronautics and Aeronautics (AIAA) Book Series, Vol. 179, ISBN 1-56347-255-4, 1998, and “Physics of Direct Hit and Near Miss Warhead Technology”, Volume 194, ISBN 1-56347-473-5, incorporated herein by this reference, provide additional details concerning “hit-to-kill” vehicles and blast fragmentation type warheads. Chapter 5 and Chapter 3 of these textbooks propose a kinetic energy rod warhead. 
     The primary components associated with theoretical kinetic energy rod warhead include a hull, a projectile core or bay in the hull including a number of individual lengthy cylindrical rods or projectiles, and an explosive charge in the hull about the projectile bay. When the explosive charge is detonated, the projectiles are deployed. 
     Two primary advantages of a kinetic energy rod warhead is that 1) it does not rely on precise navigation as is the case with “hit-to-kill” vehicles and 2) it provides better penetration than blast fragmentation type warheads. To date, however, kinetic energy rod warheads have not been widely accepted nor have they yet been fully deployed. Also, this concept requires a fuse to determine when to deploy the rods. Even though it does not need to be as accurate as the blast fragmentation warhead, it still must be incorporated into the vehicle. 
     Thus, those skilled in the art have endeavored to modify warheads such as the hit-to-kill vehicle to increase its lethality. Lockheed, for example, proposed a deployable fabric which surrounds the hit-to-kill vehicle and designed to impact a target in the case where the hit-to-kill vehicle does not directly strike and destroy the target. These concepts were only designed for a very small miss distance. Advanced countermeasure threats would defeat such a concept. And, with this design, it is possible for submunitions to escape destruction and thus the deployable fabric design did not gain wide acceptance. Also, the fabric does not penetrate thick payloads when compared to high density rods. The fabric concept is only required to slap the target with an impulse cause a delayed kill. Those types of kills are not accepted today and more lethal concepts are required. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of this invention to provide a hit-to-kill vehicle which is able to destroy a nuclear target and/or its submunitions even if the main body of the hit-to-kill misses the target and/or fails to destroy a submunition. 
     It is a further object of this invention to provide such a hit-to-kill vehicle which exhibits the benefits and the advantages of both hit-to-kill vehicles and kinetic energy rods when engaging a complex counter threat. 
     This invention results from the realization that a higher lethality hit-to-kill vehicle is effected by the addition of a deployable net which positions a number of spaced kinetic energy rod warhead rods or projectiles in an array in space about the main body of the hit-to-kill vehicle to destroy nuclear targets and/or their submunitions even if the main body of the hit-to-kill vehicle does not. This concept does not require a fuse because the rods are held (fixed) in place. The spray pattern density is constant and fusing errors are not even considered. Since this concept is used in outer space, there no air drag on the deployed net. The net travels along with the kill vehicle killing the target given an off hit engagement. 
     This invention features a warhead comprising a hit-to-kill vehicle and a hub about the hit-to-kill vehicle including packaged therein a net, means for deploying the net, and a plurality of rods attached to the net for destroying a target when the net is deployed in the vicinity path of the target in case the hit-to-kill vehicle misses the target. 
     In one embodiment, the means for deploying the net includes an inflatable superstructure with a plurality of inflatable vanes and a circumferential inflatable ring. In another embodiment, the means for deploying the net includes thrusters attached to the periphery of the net. 
     The net may be round and include vertical members intersecting horizontal members or circular members intersecting axially extending members. Typically, the net includes intersecting members and the rods are disposed at the intersection of the members. 
     One method of destroying a target in accordance with this invention includes positioning a hit-to-kill vehicle in the trajectory path of a target and deploying a net including a plurality of rods held in a spaced relationship by the net for destroying the target in case the hit-to-kill vehicle misses the target. 
     One method of manufacturing a warhead in accordance with this invention features packaging a net, means for deploying the net, and a plurality of rods attached to the net in a hub and attaching the hub to a hit-to-kill vehicle. A plurality of rods are secured at the interstices of a net, the net is packaged in a hub and the hub is coupled to a hit-to-kill vehicle. 
     In the deployed configuration, the warhead of this invention includes a hit-to-kill vehicle, a hub about the hit-to-kill vehicle, a net extending outward from the hub, and 
     a plurality of rods attached to the net for destroying a target when the net is deployed in the vicinity path of the target in case the hit-to-kill vehicle misses the target. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       Other objects, features and advantages will occur to those skilled in the art from the following description of a preferred embodiment and the accompanying drawings, in which: 
         FIG. 1  is a schematic view showing the deployment of a prior art hit-to-kill vehicle; 
         FIG. 2  is a schematic three dimensional view of a prior art hit-to-kill vehicle; 
         FIG. 3  is a schematic three dimensional view showing the modified hit-to-kill vehicle of the subject invention; 
         FIG. 4  is a schematic three dimensional view showing the deployment of the net of the subject invention about the hit-to-kill vehicle; 
         FIG. 5  is a schematic three dimensional view showing another embodiment of a deployable net in accordance with the subject invention; 
         FIG. 6  is a schematic three dimensional view showing a portion of the net of  FIG. 5 ; and 
         FIG. 7  is a schematic three dimensional view showing another design for a deployable net in accordance with the subject invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
     As discussed in the background section above, hit-to-kill vehicles are typically launched into a position proximate re-entry vehicle  10 ,  FIG. 1  or other target via missile  12 . Hit-to-kill vehicle  14  is navigatable and designed to strike re-entry vehicle  10  to render it inoperable. Counter measures, however, can be used to avoid kill vehicle  14 . Vector  16  shows kill vehicle  14  missing re-entry vehicle  10 . Moreover, nuclear or biological bomblets and chemical submunition payloads  18  are carried by some threats and one or more of these bomblets or chemical submunition payloads  18  can survive, as shown at  20 , and cause heavy casualties even if kill vehicle  14  does accurately strike target  10 .  FIG. 2  shows hit-to-kill vehicle  14  in more detail. 
     In this invention, hit-to-kill  14 ′,  FIG. 3  is modified to include hub  30  encircling vehicle  14 . Hub  30  includes a net, means for deploying the net, and a plurality of kinetic energy rod warhead rods packaged therein preferably secured to the net at the interstices thereof. 
       FIG. 4  shows net  40  deployed and rods  50  held in a spaced relationship by the net. In this embodiment, the means for deploying net  40  is an inflatable superstructure including inflatable vanes  60  and circumferential inflatable ring  62 . In this example, 20 foot diameter net  40  is round and includes vertical nylon members  70  intersecting horizontal nylon members  72 . Rods  50  are secured at the intersection of all or most of such members. The primary purpose of net  40  is to orient rods  50  in a spaced relationship in order to destroy a target or submunitions not destroyed by the main body of hit-to-kill vehicle  14 ′. In the example shown in  FIG. 4 , fabric layer  80  may also be used in connection with net  40 . A gas generator connected to the inflatable superstructure inflates the vanes  60  and ring  62 . 
     The advantage of this system over a kinetic energy rod warhead is that the density of the rods in space is held constant. In a kinetic energy rod warhead, in contrast, the density of the rods deployed as projectiles decreases rapidly after deployment. Those skilled in the art will know how to select the appropriate density for the rods by fabricating nets of different configurations. 
     In the embodiment of  FIGS. 5-6 , small thrusters  90 , attached to the periphery of net  40  are the means for deploying net  40 . Rods  50  may be made of titanium and cylindrical in shape although the other rod shapes disclosed in U.S. patent application Ser. No. 10/162,498, incorporated herein by this reference, may also be used. 
     In  FIG. 7 , net  40 ′ includes circular members  100  intersecting radially extending members  102 . As shown, the main body of the hit-to-kill vehicle has missed target  104  but since the net is deployed in the vicinity of the target, rods or projectiles  50 , held in a fixed spaced position in space, will destroy target  104 . 
     The net may be deployed by thrusters as discussed above with reference to  FIG. 5  or by the addition of an inflatable superstructure as discussed above with reference to  FIG. 4 , and/or a combination of both designs. Thus, the hit-to-kill vehicle of the subject invention has enhanced lethality due to the addition of the kinetic energy rods held in a fixed spaced relation by the net and is thus able to destroy a nuclear target and/or its submunitions even if the main body of the hit-to-kill vehicle misses the target and/or fails to destroy a submunition. The result is a system which exhibits the benefits and advantages of both hit-to-kill vehicles and kinetic energy rod warheads. Fusing is typically not required as is the case with the Lockheed fabric design. 
     Although specific features of the invention are shown in some drawings and not in others, this is for convenience only as each feature may be combined with any or all of the other features in accordance with the invention. The words “including”, “comprising”, “having”, and “with” as used herein are to be interpreted broadly and comprehensively and are not limited to any physical interconnection. Moreover, any embodiments disclosed in the subject application are not to be taken as the only possible embodiments. 
     Other embodiments will occur to those skilled in the art and are within the following claims: