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OBJECTIVE: Demonstrate the feasibility of a reusable forward closure that allows payload egress without producing debris or environmentally hazardous materials. Additionally, the new concepts must satisfy the requirements of the current closure system such as protecting the payload from the underwater environment and imparting minimal loads on the payload front end during launch. DESCRIPTION: Before a payload is ejected from a submarine it must typically be protected from the pressure of the ocean environment. The structure that protects the payload while it is in the launch tube is called the forward closure. During launch, the closure must not impede the payload as it exits the launch tube. Current forward closure systems use rigid structures that are separated pyrotechnically or flexible, fly-through structures to allow payload egress. In both cases the closures are destroyed and cannot be reused. In the case of rigid closures, the use of pyrotechnics increase handling costs. Also, the pyrotechnics expel environmentally hazardous material when rupturing the closure. Both rigid and fly-through closures come into contact with the payload front end during egress resulting in a load force. The goal of this project is to develop an innovative closure system that will support a variety of payloads and minimize or eliminate contact loads on the payload nose without producing debris. A challenging constraint for this type of closure system is the need to protect against external forces but also allow payload egress even if the closure fails to respond. In other words, the proposed technology must have an inherent backup capability to limit payload front end loads even in the event of power loss or command loss to the closure. Typically, closures made from stronger materials impart larger forces on the payload during egress. For past and current submarine launched weapons, a non-destructive, reusable closure has not been realized in part because of the technical challenges involved. Past closure technologies, such as frangible structures, flexible membranes, or hard pyrotechnically separated shells are all necessarily destroyed when the payload egresses. A new technology is needed to allow payload egress without destruction of the closure itself. A reusable closure system needs to perform the same functions as a traditional closure in a demanding environment. These functions include protection of flight payloads from hydrostatic pressures of up to 150 psi and ability to allow the payload to egress during launch without interference. The closure should offer fast response and reaction times on the order of milliseconds. The target payload size will be between 30 to 40 inches full scale; however, the functionality of the proposed technology could be demonstrated at a subscale level. This topic is looking for new innovative technologies or concepts that provide equivalent performance as current systems with additional capabilities that minimize impacts to the payload and support reusability. PHASE I: Determine the technical feasibility of a reusable closure. Use analysis, modeling and simulation, or subscale bench testing to prove the feasibility of the proposed concept. Complete the concept study of the closure system key components. Perform a study to examine potential scaling issues PHASE II: Complete the design of the proposed system. Produce a subscale prototype reusable closure and demonstrate its predicted performance through testing. PHASE III: Technology would be transitioned to the Ohio Replacement Program (OR Program) technology portfolio for inclusion in the OR Program. PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: A cost effective, reusable closure that allows launch of payloads and provides protection against high pressures will have a variety of commercial and military applications. Applications in the private sector include rapid, low cost deployment of sensors and sono-buoys from ships and underwater vehicles for oceanographic data collection, pollution monitoring, and offshore exploration. A closure that allows reset to its original state would support the undersea recovery of sensors by the deployment vehicle. REFERENCES: 1) Mussey, Richard A.,"Launch Tube Closure."US Patent 4301708. 24 Nov. 1981. 2) Callahan, Jeffrey C.,"Submarine Horizontal Launch TACTOM Capsule."US Patent 6427574 B1. 6 Aug. 2002. 3) Paul, Buddy R.,"Article Comprising a Canister Closure with Pressure-Pulse Release."US Patent 7685920 B2. 30 Mar. 2010. 4) Stephen J. Plunkett, Richard E. Dooley,"Launch tube system having inflatable bladder shock isolation."US Patent 7128013. Issued 31 Oct 2006.
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