Particle contamination launch redistribution and effects on the low-earth-orbit infrared SPHEREx telescope

The Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer (SPHEREx) is a Jet Propulsion Laboratory (JPL) and Caltech led mission which will perform the first near-infrared all-sky survey to address the goals of NASA's astrophysics division. SPHEREx accomplishes these surveys of the entire celestial sphere with an infrared telescope cooled to cryogenic temperatures by a passive thermal system. Because the SPHEREx payload has both an optical telescope and a passive thermal system, it is highly sensitive to particulate contamination In this work the JPL Contamination Control (CC) group develops a computational physics framework to model particulate transport contamination from the fairing environment during launch, which is the largest particulate contamination source for most missions. Even with strict contamination control during ground processing, the launch environment can induce enough particulate contamination to exceed the scientific requirements of sensitive missions. For SPHEREx, particulate contamination in the telescope has a direct impact on the quality of the scientific data gathered during the surveys. Additionally, particulate contamination of the thermal system has a detrimental effect on its ability to cool the instrument to its cryogenic operating temperatures and maintain temperature stability. Due to these sensitivities it is imperative for SPHEREx that the particulate contamination from launch be comprehensively understood and mitigated wherever possible. The computational physics framework developed in this work is used to obtain precise estimates of particulate contamination on the SPHEREx payload and provides mitigations to ensure the mission meets its scientific requirements.