Published: Jan 2009
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Metallic contaminant was found in the liquid oxygen (LOX) prevalve screen of the shuttle main engine propulsion system on two orbiter vehicles. To investigate the potential for an ignition, NASA Johnson Space Center White Sands Test Facility performed (modified) rotating friction ignition testing in LOX. This testing simulated a contaminant particle in the low-pressure oxygen turbo pump (LPOTP) and the high-pressure oxygen turbo pump (HPOTP) of the shuttle main propulsion system. Monel® K-500 and Inconel® 718 samples represented the LPOTP and HPOTP materials. Aluminum foil tape and titanium foil represented the contaminant particles. In both the Monel® and Inconel® material configurations, the aluminum foil tape samples did not ignite after 30 s of rubbing. In contrast, all of the titanium foil samples ignited regardless of the rubbing duration or material configuration. However, the titanium foil ignitions did not propagate to the Monel and Inconel materials. Based on these results, NASA determined that the risk of a fire occurring in the turbo pumps was acceptably low.
rotating friction ignition testing, liquid oxygen environment, aluminum, titanium, metallic contaminant particles
Peralta, Stephen F.
Mechanical Engineer, NASA Test and Evaluation Contract, Las Cruces, NM
Rosales, Keisa R.
Chemical Engineer, NASA Test and Evaluation Contract, Las Cruces, NM
Stoltzfus, Joel M.
Project Manager, NASA White Sands Test Facility, Las Cruces, NM