Abstract
The Galileo spacecraft, which will use an earth-storable, bipropellant integral propulsion system, is potentially susceptible to oxidizer flow decay. The risk has increased since the spacecraft was initially designed due to mission changes which will more than double spacecraft operational life. Various actions can be taken to reduce the risk of flow decay on Galileo, but there is not currently enough specific, quantitative flow decay data available with which to develop a sound flow decay avoidance strategy. The work documented here began with a review of the existing body of flow decay research, looking both at the corrosion rate of stainless steel in contact with NTO (i.e., the contamination rate of the propellant with iron) and at the solubility of iron nitrate in nitrogen tetroxide (i.e., the precipitation of that contaminant in a form to clog propulsion system components). An effort was made to understand the fundamental chemical mechanisms involved, but it proved unsuccessful due to the limited amount of work currently available on the subject. Existing experimental results were used directly to bound the problem; these data were normalized to Galileo conditions only as regards surface-to-volume ratio. Based on the results of the data review, it became clear that additional experimental data were required. A test program was designed, and testing to better determine potential Galileo corrosion and solubility data is in progress. Based on the data obtained, the necessary action or combination of actions to preclude flow decay on Galileo will be implemented.
Original language | English (US) |
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Title of host publication | AIAA, SAE, ASME, and ASEE 23rd Joint Propulsion Conference |
Place of Publication | New York, NY |
Publisher | American Institute of Aeronautics and Astronautics Inc. (AIAA) |
Number of pages | 17 |
DOIs | |
State | Published - Jul 1 1987 |
Externally published | Yes |