Summary of the Development of a Demiseable Composite Overwrapped Hydrazine Tank for the Global Precipitation Measurement Mission from Concept to Delivery

Abstract

NASA's Global Precipitation Measurement (GPM) mission is an ongoing Goddard Space Flight Center (GSFC) project whose basic objective is to improve global precipitation measurements. The GPM spacecraft is designed to minimize surviving debris upon its controlled reentry at the end of its life. This requirement resulted in the need for much of its structure and many of its components including its propellant tank to demise or ablate during re-entry. The GPM mission’s hydrazine tank is the world’s first spacecraft tank specifically designed to demise upon reentry. The GPM tank is a Composite Overwrapped Pressure Vessel (COPV) that consists of an aluminum Propellant Management Device (PMD) inside an aluminum liner overwrapped with carbon fiber. Demise calculations have shown that this configuration will demise. For a hydrazine spacecraft tank the use of a fully overwrapped COPV, the use of aluminum for the liner material, and the use of an allaluminum PMD are all somewhat unusual. The use of aluminum for the PMD was expected to be the key challenge for the flight tank effort. The initial studies prior to the start of the flight tank development highlighted some of the difficulties in using aluminum for a highly wettable PMD. The initial studies showed that PMD surfaces could be made wettable by the use of a special treatment process but that contamination control would be a key issue. Initial analyses followed by concept studies began at GSFC in 2002. Focused study contracts followed the initial concept studies. The flight tank development and delivery effort began with a contract award in August of 2008. The flight tank was ready for installation into the GPM spacecraft in April of 2011. The flight qualification of the tank concluded with a successful qualification burst test in September of 2011. This paper will provide a summary of the efforts by the NASA/Contractor team from initial demise analyses to concept studies to flight development to flight tank qualification and delivery of the unique GPM flight tank.