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Title: Analytical and experimental studies of leak location and environment characterization for the international space station

The International Space Station program is developing a robotically-operated leak locator tool to be used externally. The tool would consist of a Residual Gas Analyzer for partial pressure measurements and a full range pressure gauge for total pressure measurements. The primary application is to demonstrate the ability to detect NH{sub 3} coolant leaks in the ISS thermal control system. An analytical model of leak plume physics is presented that can account for effusive flow as well as plumes produced by sonic orifices and thruster operations. This model is used along with knowledge of typical RGA and full range gauge performance to analyze the expected instrument sensitivity to ISS leaks of various sizes and relative locations (“directionality”). The paper also presents experimental results of leak simulation testing in a large thermal vacuum chamber at NASA Goddard Space Flight Center. This test characterized instrument sensitivity as a function of leak rates ranging from 1 lb{sub m/}/yr. to about 1 lb{sub m}/day. This data may represent the first measurements collected by an RGA or ion gauge system monitoring off-axis point sources as a function of location and orientation. Test results are compared to the analytical model and used to propose strategies for on-orbitmore » leak location and environment characterization using the proposed instrument while taking into account local ISS conditions and the effects of ram/wake flows and structural shadowing within low Earth orbit.« less
Authors:
; ;  [1] ; ;  [2] ; ;  [3] ; ;  [4] ; ; ;  [5] ;  [6] ; ; ; ;  [7] ;  [8] ;  [9]
  1. Stinger Ghaffarian Technologies, Inc, 7701 Greenbelt Rd, Greenbelt, MD 20770 (United States)
  2. Alliant Techsystems, Inc, 5050 Powder Mill Road, Beltsville, Maryland 20705 (United States)
  3. Lockheed Martin, 1300 Hercules, Houston, TX 77058 (United States)
  4. NASA Johnson Space Flight Center, 2101 NASA Pkwy, Houston, TX 77058 (United States)
  5. Conceptual Analytics, 8209 Woburn Abbey Rd, Glenn Dale, MD 20769 (United States)
  6. ASRC Federal Space and Defense, 7000 Muirkirk Meadows Drive, Suite 100, Beltsville, MD 20705 (United States)
  7. NASA Goddard Space Flight Center, 8800 Greenbelt Rd, Greenbelt, MD 20771 (United States)
  8. Jackson and Tull, 7375 Executive Pl, Lanham, MD 20706 (United States)
  9. Wyle STE Group, 1290 Hercules Ave, Houston, TX 77058-2769 (United States)
Publication Date:
OSTI Identifier:
22390569
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1628; Journal Issue: 1; Conference: 29. International Symposium on Rarefied Gas Dynamics, Xi'an (China), 13-18 Jul 2014; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; AMMONIA; COMPARATIVE EVALUATIONS; CONTROL SYSTEMS; GAS FLOW; INTERNATIONAL SPACE STATION; LEAKS; MATHEMATICAL MODELS; MONITORING; NASA; ORBITS; ORIFICES; PARTIAL PRESSURE; PLUMES; PRESSURE CONTROL; PRESSURE GAGES; PRESSURE MEASUREMENT; SENSITIVITY; SPACE FLIGHT