Survey of materials for hydrazine propulsion systems in multicycle extended life applications

An assessment is presented of materials compatibility data for hydrazine monopropellant propulsion systems applicable to the Space Shuttle vehicle missions. Materials were evaluated for application over a 10-yr/100-mission operational lifetime with minimum refurbishment. A general materials compatibility rating for a broad range of materials and several propellants based primarily on static liquid propellant immersion testing and an in-depth evaluation of hydrazine decomposition as a function of purity, temperature, material, surface conditions, etc., are presented. The most promising polymeric material candidates for propellant diaphragms and seals appear to have little effect on increasing hydrazine decomposition rates, but the materials themselves do undergo changes in physical properties which can affect their 10-yr performance in multicycle applications. The available data on these physical properties of elastomeric materials as affected by exposure to hydrazine or related environments are presented.