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Liquid-Propellant Rocket Engine Throttling: A Comprehensive ReviewLiquid-Propellant Rocket Engines (LREs) are capable of on-command variable thrust or thrust modulation, an operability advantage that has been studied intermittently since the late 1930s. Throttleable LREs can be used for planetary entry and descent, space rendezvous, orbital maneuvering including orientation and stabilization in space, and hovering and hazard avoidance during planetary landing. Other applications have included control of aircraft rocket engines, limiting of vehicle acceleration or velocity using retrograde rockets, and ballistic missile defense trajectory control. Throttleable LREs can also continuously follow the most economical thrust curve in a given situation, compared to discrete throttling changes over a few select operating points. The effects of variable thrust on the mechanics and dynamics of an LRE as well as difficulties and issues surrounding the throttling process are important aspects of throttling behavior. This review provides a detailed survey of LRE throttling centered around engines from the United States. Several LRE throttling methods are discussed, including high-pressure-drop systems, dual-injector manifolds, gas injection, multiple chambers, pulse modulation, throat throttling, movable injector components, and hydrodynamically dissipative injectors. Concerns and issues surrounding each method are examined, and the advantages and shortcomings compared.
Document ID
Acquisition Source
Marshall Space Flight Center
Document Type
Conference Paper
Casiano, Matthew
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Hulka, James
(Jacobs Engineering Group, Inc. Huntsville, AL, United States)
Yang, Virog
(Georgia Inst. of Tech. Atlanta, GA, United States)
Date Acquired
August 24, 2013
Publication Date
August 2, 2009
Subject Category
Spacecraft Propulsion And Power
Report/Patent Number
Meeting Information
Meeting: 45th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit
Location: Denver, CO
Country: United States
Start Date: August 2, 2009
End Date: August 5, 2009
Sponsors: American Society for Electrical Engineers, Society of Automotive Engineers, Inc., American Inst. of Aeronautics and Astronautics, American Society of Mechanical Engineers
Distribution Limits
Public Use Permitted.
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