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Iridium-Coated Rhenium Radiation-Cooled RocketsRadiation-cooled rockets are used for a range of low-thrust propulsion functions, including apogee insertion, attitude control, and repositioning of satellites, reaction control of launch vehicles, and primary propulsion for planetary space- craft. The key to high performance and long lifetimes for radiation-cooled rockets is the chamber temperature capability. The material system that is currently used for radiation-cooled rockets, a niobium alloy (C103) with a fused silica coating, has a maximum operating temperature of 1370 C. Temperature limitations of C103 rockets force the use of fuel film cooling, which degrades rocket performance and, in some cases, imposes a plume contamination issue from unburned fuel. A material system composed of a rhenium (Re) substrate and an iridium (Ir) coating has demonstrated operation at high temperatures (2200 C) and for long lifetimes (hours). The added thermal margin afforded by iridium-coated rhenium (Ir/Re) allows reduction or elimination of fuel film cooling. This, in turn, leads to higher performance and cleaner spacecraft environments. There are ongoing government- and industry-sponsored efforts to develop flight Ir/ Re engines, with the primary focus on 440-N, apogee insertion engines. Complementing these Ir/Re engine development efforts is a program to address specific concerns and fundamental characterization of the Ir/Re material system, including (1) development of Ir/Re rocket fabrication methods, (2) establishment of critical Re mechanical properly data, (3) development of reliable joining methods, and (4) characterization of Ir/Re life-limiting mechanisms.
Document ID
Document Type
Technical Memorandum (TM)
Reed, Brian D. (NASA Lewis Research Center Cleveland, OH United States)
Biaglow, James A. (NASA Lewis Research Center Cleveland, OH United States)
Schneider, Steven J. (NASA Lewis Research Center Cleveland, OH United States)
Date Acquired
August 17, 2013
Publication Date
July 1, 1997
Subject Category
Metallic Materials
Report/Patent Number
NAS 1.15:107453
Meeting Information
International Symposium on Rhenium and Rhenium Alloys(Orlando, FL)
Funding Number(s)
Distribution Limits
Work of the US Gov. Public Use Permitted.

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NameType 19970036365.pdf STI