Ammunition and explosives – Igniting devices and systems – Ignition or detonation circuit
Reexamination Certificate
2001-09-07
2004-04-13
Johnson, Stephen M. (Department: 3641)
Ammunition and explosives
Igniting devices and systems
Ignition or detonation circuit
C102S201000, C102S218000
Reexamination Certificate
active
06718881
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ordnance control and initiation systems and methods useful for managing and controlling the activation of ordnance, for example, such as those used for stage separation in flight vehicles. The system and method, for example, may relate not only to ordnance safing, arming and initiation, but monitoring and telemetry acquisition as well.
2. Description of the Related Art
There are numerous applications in which it is necessary or desirable to control and/or initiate ordnance with high precision and reliability. One such application, although merely illustrative and not by way of limitation, involves the ordnance associated with rockets, missiles, and similar powered flight vehicles (hereinafter “flight vehicles”). It is not uncommon for such vehicles to include a plurality of ordnance devices for performing interrelated or distinct tasks. By way of example, a flight vehicle may contain multiple stages, with each stage having its own distinct ordnance in the form of a gas generant or propellant. In some instances, a flight vehicle stage may have multiple gas generants or propellants, such as found in the case of rocket motor stages having main and divert motors. Each of these gas generants and propellants typically has its own distinct initiator for activating (directly or by an ignition train) the gas generant and propellant.
Another illustrative use of ordnance devices in multi-stage flight vehicles involves stage separation. As a lower stage is depleted of gas generant or propellant, the depleted lower stage must be separated from the remaining upper stage or stages before the next stage can be fired. This stage separation is typically performed with ordnance devices, each of which must be activated with precise timing for successful stage separation.
Another example of the use of ordnance devices on a flight vehicle, especially a multi-stage flight vehicle, can be found at the uppermost or “kill” stage of a missile. The kill stage often has a first ordnance device in the form of a gas generant or propellant for propelling the kill stage, and a second ordnance device in the form of an explosive for imparting maximum damage to its intended target.
Further examples of ordnance device applications on flight vehicles include the use of solid or liquid fuel ordnances on launch vehicles for propelling devices, such as satellites, into space. As yet another example, a flight vehicle may contain destruct (explosive) ordnances for destroying the vehicle or its cargo or payload in the event of a malfunction or error in launch trajectory or flight control.
The ordnance devices of flight vehicles require an ignition event for activation of the ordnance device or initiation of an ignition train that results in activation of the ordnance device. Typically, each ordnance device of a flight vehicle is associated with its own initiator. The initiator typically includes a squib having a bridge wire and pyrotechnic material. A pyrotechnic reaction is initiated by sending electrical energy to the squib, which converts the electrical energy to thermal energy until the bridge wire reaches a sufficiently high temperature to ignite the pyrotechnic material of the squib. The pyrotechnic material then either ignites the propellant/gas generant directly or ignites an ignition train that leads to the ignition of the propellant/gas generant.
Known electrical ignition systems have several drawbacks. Perhaps the most significant one is the possibility of unintentional activation of the ordnance, e.g., caused by unwanted and unplanned electromagnetic energy or fields, such as electromagnetic interference, lightning, electrostatic discharge, etc. This drawback in some cases and to some extent may be mitigated by heavily shielding the electrical system to shield it against such external electrical phenomena. However, shielding of the electrical system adds production costs and makes testing and installation difficult. It also adds to system mass.
Another drawback of some known electrical ordnance systems is their requirement for sometimes lengthy and relatively heavy conductor cabling, such as twisted pair cabling, and the associated shielding and harnesses. Such systems can be disadvantageous, for example, based on their relatively high mass penalties, relatively substantial installation requirements, and high rework difficulty. Electrical conductors also can be subject to relatively substantial power losses when they run for significant distances. Large, heavy pyrotechnic controller black boxes often are required to interface commands from the command computer to the ordnance devices.
It is often desirable in ordnance applications to have the flexibility to scale the system, for example, by adding additional ordnance devices. When this is done with many known systems, it typically requires additional control circuits and cabling. As a consequence, for example, it is often not feasible or unduly difficult or penalizing to integrate a telemetry system with the ordnance system. In such cases it is often necessary for the transmission lines and controllers of the telemetry and ordnance systems to remain discrete from each other.
Another approach, often used as an alternative to the electrical activation system, involves the use of electro-optics. In such systems, for example, electrical control and/or initiation signals are converted into optical signals and transmitted via optical signal conduits, such as a fiber optic cable. The optical energy is used to transmit power and optionally commands through an optical fiber system to the squib. Such systems, however, also may have drawbacks. For one, the power transmission capacity of optical conduits typically is relatively limited. Moreover, optical transmission can be subject to substantial energy loss over long distances, particular at relatively high power levels. For this reason, optical initiation systems are often are not suitable for large vehicles having lengthy optical conduits. optical transmission. Another drawback in some electro-optic systems involves the potentially substantial amount of cabling or optical conduit runs to couple the controller to the ordnance devices.
OBJECTS OF THE INVENTION
Accordingly, an object of the present invention is an ordnance control and initiation system and method that are reliable relative to known systems and methods, and thus which limit or preclude inadvertent ignition of the ordnance.
It is another object of the invention to provide an ordnance control and initiation system and method that can have lower overall mass relative to known systems and methods having like overall functional capability.
It is also an object of the invention to provide an ordnance control and initiation system and method that offer the flexibility to be scalable.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations pointed out in the appended claims.
SUMMARY OF THE INVENTION
To achieve the foregoing objects, and in accordance with the purposes of the invention as embodied and broadly described in this document, an ordnance control and initiation system is provided. It comprises a plurality of ordnance devices comprising a plurality of sets of the ordnance devices. Each set of the ordnance devices comprises at least one of the ordnance devices and an ordnance device interface. The system also comprises a controller for issuing state commands, a master ignition control module operatively coupled to the controller to receive the state commands and re-transmit the state commands, and a plurality of slave ignition control modules. Each of the slave ignition control modules is associated with one of the sets of the ordnance devices and is operatively coupled to the master ignition control
Alliant Techsystems Inc.
Johnson Stephen M.
TraskBritt
LandOfFree
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