Characterization of the Performance and Failure Mechanisms of the Hydrazine Propulsion System of ISEE-3

After travelling through space dormant for 27 years, hopes were high for the reactivation of the hydrazine propulsion system on the International Sun Earth Explorer 3. While many of the onboard systems were still operational when contact was reestablished in 2014, the propulsion system was no longer able to change the spacecraft trajectory. The formulation of a single cohesive theory of how the system failed provides an opportunity to study the properties of a spacecraft that outlived its design lifetime by more than 30 years, and to apply lessons learned to future designs. This thesis describes observations made about the performance of the propulsion system during commanding in 2014 that led to the determination that the nitrogen pressurant from the propulsion system had been lost. The focus is on the mechanism by which the pressurant disappeared between 1987 and 2014 without catastrophic failure of the spacecraft or even the loss of the majority of the fuel. Scenarios are proposed to explain these observations, and the results of simulations designed to test these scenarios are presented. Analysis of all simulations led to the conclusion that the most likely scenario accounting for system failure was a micrometeoroid impact near the bottom of the spacecraf