Demonstration of rapid and sensitive module leak certification for space station freedom
- Brookhaven National Lab., Upton, NY (United States)
A leak detection and quantification demonstration using perflurocarbon tracer (PFT) technology was successfully performed at the NASA Marshall Space Flight Center on January 25, 1991. The real-time Dual Trap Analyzer (DTA) at one-half hour after the start of the first run gave an estimated leak rate of 0.7 mL/min. This has since been refined to be 1.15 {plus minus} 0.09 mL/min. The leak rates in the next three runs were determined to be 9.8 {plus minus} 0.7, {minus}0.4 {plus minus} 0.3, and 76 {plus minus} 6 mL/min, respectively. The theory on leak quantification in the steady-state and time-dependent modes for a single zone test facility was developed and applied to the above determinations. The laboratory PFT analysis system gave a limit-of-detection (LOD) of 0.05 fL for ocPDCH. This is the tracer of choice and is about 100-fold better than that for the DTA. Applied to leak certification, the LOD is about 0.00002 mL/s (0.000075 L/h), a 5 order-of-magnitude improvement over the original leak certification specification. Furthermore, this limit can be attained in a measurement period of 3 to 4 hours instead of days, weeks, or months. A new Leak Certification Facility is also proposed to provide for zonal (three zones) determination of leak rates. The appropriate multizone equations, their solutions, and error analysis have already been derived. A new concept of seal-integrity certification has been demonstrated for a variety of controlled leaks in the range of module leak testing. High structural integrity leaks were shown to have a linear dependence of flow on {Delta}p. The rapid determination of leak rates at different pressures is proposed and is to be determined while subjecting the module to other external force-generating parameters such as vibration, torque, solar intensity, etc. 13 refs.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States); NASA Marshall Space Flight Center (MSFC), Huntsville, AL (United States)
- Sponsoring Organization:
- USDOE; USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC02-76CH00016
- OSTI ID:
- 5231609
- Report Number(s):
- BNL-47242; ON: DE92014168
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
42 ENGINEERING
LEAK DETECTORS
TESTING
SPACE VEHICLES
LEAKS
DETECTION
FLOW RATE
LIMITING VALUES
MATHEMATICAL MODELS
PERFORMANCE
PROGRESS REPORT
SENSITIVITY
SPACE VEHICLE COMPONENTS
DOCUMENT TYPES
VEHICLES
440800* - Miscellaneous Instrumentation- (1990-)
420200 - Engineering- Facilities
Equipment
& Techniques