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J-2X Abort System DevelopmentThe J-2X is an expendable liquid hydrogen (LH2)/liquid oxygen (LOX) gas generator cycle rocket engine that is currently being designed as the primary upper stage propulsion element for the new NASA Ares vehicle family. The J-2X engine will contain abort logic that functions as an integral component of the Ares vehicle abort system. This system is responsible for detecting and responding to conditions indicative of impending Loss of Mission (LOM), Loss of Vehicle (LOV), and/or catastrophic Loss of Crew (LOC) failure events. As an earth orbit ascent phase engine, the J-2X is a high power density propulsion element with non-negligible risk of fast propagation rate failures that can quickly lead to LOM, LOV, and/or LOC events. Aggressive reliability requirements for manned Ares missions and the risk of fast propagating J-2X failures dictate the need for on-engine abort condition monitoring and autonomous response capability as well as traditional abort agents such as the vehicle computer, flight crew, and ground control not located on the engine. This paper describes the baseline J-2X abort subsystem concept of operations, as well as the development process for this subsystem. A strategy that leverages heritage system experience and responds to an evolving engine design as well as J-2X specific test data to support abort system development is described. The utilization of performance and failure simulation models to support abort system sensor selection, failure detectability and discrimination studies, decision threshold definition, and abort system performance verification and validation is outlined. The basis for abort false positive and false negative performance constraints is described. Development challenges associated with information shortfalls in the design cycle, abort condition coverage and response assessment, engine-vehicle interface definition, and abort system performance verification and validation are also discussed.
Document ID
20080030988
Document Type
Conference Paper
Authors
Santi, Louis M. (Jacobs Technologies Engineering Science Contract Group Houston, TX, United States)
Butas, John P. (NASA Marshall Space Flight Center Huntsville, AL, United States)
Aguilar, Robert B. (Pratt and Whitney Rocketdyne United States)
Sowers, Thomas S. (Analex Corp. United States)
Date Acquired
August 24, 2013
Publication Date
May 12, 2008
Subject Category
Space Transportation and Safety
Meeting Information
2008 JANNAF Propulsion Meeting/24th Propulsion Systems Hazards/Joint Subcommittee Meeting(Newton, MA)
Funding Number(s)
CONTRACT_GRANT: NNM05AB50C
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.