Seawater Immersion of GEM II Propellant
Abstract
Experimental data has shown that safety risks associated with GEM propellant from the 17 January 1997 Delta II flight failure diminish with time. It was shown that AP leached out of GEM propellant exposed to seawater at a logarithmic rate with a slope of 0.44 (% AP lost/week aged in seawater) and intercepts that depend on sample size. Friction and impact data on dried aged propellant samples showed no increased burning hazard compared with propellant not exposed to water. With increased seawater aging, the sensitivity of the outer surfaces of the dried propellant samples gradually decreased. The outer surface of wet propellant samples were significantly less sensitive to friction and impact than virgin propellant. Centers of wet propellant samples were found to be less sensitive than propellant not exposed to water, but definitely more sensitive than wet propellant sample surfaces. In fuel fires, initially, no differences could be observed between burning fresh propellant and dried, aged propellant. With increased seawater aging and resultant AP loss, the flame intensity of these burning aged propellants gradually decreased. During the early stages of aging, all dry samples ignited immediately and burning spread over all exposed surfaces. As seawater-aging time increased, flame spreading to all exposed surfaces gradually decreased. Finally, it was demonstrated that all wet aged samples experienced ignition delays. Ignition delays were directly related to water immersion time. These samples only burned on one face leaving an oxidizer poor rubber shell. A point was reached with the 1- and 2-in. propellant cubes where it became essentially impossible to obtain sustained combustion under the conditions used in the Fire Test.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1999
- Accession Number
- ADA362365
Entities
People
- Calude I. Merrill
- John D. O'drobinakk
Organizations
- Air Force Research Laboratory