Surface Tension PMD Tank for On Orbit Fluid Transfer

Abstract

A hydrazine propellant tank was designed and manufactured to support a mission to demonstrate on-orbit propellant transfer capabilities. To reduce program cost, a flight qualified tank shell made from Solution Treated and Aged 6Al-4V titanium was baselined. This tank shell was selected based on its qualified capabilities as well as its ability to adapt a new cantilever-mounted Propellant Management Device (PMD). Stress and fracture mechanics analyses were conducted to validate the tank shell for the new mission. The tank shell qualification was by analysis only, without protoflight testing, due to large analytical margins of safety. A surface tension PMD was custom-designed for the mission. This PMD must be capable of transferring both gas-free propellant and liquid-free pressurant upon demand. The PMD performance analysis utilized the same design methodology and conservative approaches as all previous PMD design efforts. A PMD structural analysis was conducted to validate the mechanical elements. The passive, all-titanium PMD design was robust, efficient, and highly reliable.