NASA - National Aeronautics and Space Administration

A space shuttle extravehicular mobility unit (spacesuit and life-support backpack) was destroyed in a flash fire during a functional test in the Johnson Space Center's crew systems laboratory. A technician standing next to the suit received second-degree burns over his upper body during the accident. The fire originated in an aluminum bodied regulator and valve assembly when 6000-psi (41-MPa) oxygen was released through the valve into the regulator. It was postulated that the fire was probably caused by:

• Rupture of a thin, internal section of the aluminum body
• Ignition of a silicone O-ring by compression heating of the oxygen, or
• Particle impact.

As a result of the postfire investigation, the regulator and valve assembly were redesigned, and the aluminum in this assembly was replaced with Monel^®. This change and several others were implemented in the version of the suit that is in use today. The materials combustion work now being done at WSTF is geared toward understanding and preventing this type of fire.


For additional information, contact Joel Stoltzfus, (575) 524-5731.