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Miniature Extendable Nozzles or Actuating Nozzles for Improved ISP of DACS Thrusters


OBJECTIVE: The Missile Defense Agency (MDA) is seeking innovative solutions for improving the specific impulse (ISP) of kill vehicle Divert and Attitude Control Thrusters (DACS) Thrusters. This topic should focus on low-weight methods of extending or actuating DACS size nozzles to increase expansion ratio with high reliability. Discussions of alternative solutions are welcome. DESCRIPTION: Future Missile Defense Weapon Systems will need to increase divert capability (acceleration) to perform mission requirements. Increased mass flow out the nozzle by higher temperature propellant is limited by the thermal limits of advanced materials. ISP may also be increased by increasing the velocity of the propellant exiting the nozzle. DACS systems typically are carried in the nosecone of a missile interceptor and the volume available to store the DACS thrusters is limited. The typical thruster will have a minimum length bell nozzle with the expansion ratio limited by the length available to store the nozzle. Considerable work has been completed in the past on mechanical nozzle extensions to increase the expansion area and several expandable nozzle designs are currently in use but they are typically heavy and used for small increases in exit velocity. DACS thrusters are used in an exo-atmosphere near vacuum environment and can potentially be expanded much further than expandable nozzles designed for use in the atmosphere. Weight is critical for DACS thrusters and any nozzle extension system must be low weight. The extension system must also be highly reliable. If the nozzle extension fails to actuate correctly, the effective thrust from the thruster will be greatly reduced and the DACS will become severely imbalanced. The MDA is seeking thrust levels that range between 100 350 lbf with nozzle expansion ratios greater than 24 that can operate at a minimum of 1 minute while operating on a gas generator at 5500F. Solutions utilizing divert change control systems other than DACS thrusters are welcome. PHASE I: During the Phase I contract, The proposer shall conduct a design study that shows the feasibility of the concept including numerical simulation of the proposed approach. They proposer shall trade the additional mass added to the system against the system performance and compare to traditional nozzles of equivalent properties. The proposer shall provide estimated performance and reliability characteristics. PHASE II: If selected for a Phase II, the proposer shall fabricate the nozzle concept for testing. Testing should include multiple initial tests that demonstrate the deployment of the concept. Phase II should conclude with hot fire testing of the concept in a vacuum. The proposer shall provide performance and reliability estimates. PHASE III: Phase III selections will have adequate support from a MDA Prime or Propulsion vendor. The proposer shall continue testing and development with a MDA Prime or Propulsion vendor to refine performance and reliability characteristics. COMMERCIALIZATION: Commercial Satellite Control
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