The Return of the ICPS: A Statistical Perspective on Artemis Upper Stage Disposal

Prior to the launch of Artemis I, it was discovered that the Interim Cryogenic Propulsion Stage (ICPS) of the Space Launch System may not dispose heliocentrically as intended. This paper summarizes the results of an investigation which looked into why the ICPS may return in less than a year for certain Launch Days. Evidence is presented showing the ICPS mimics the behavior of known Three-Body Periodic Orbits for certain Sun-Earth geometries. This paper discusses the primary mechanisms causing ICPS to return, describes the statistics of these returns, and also discusses interactions between Artemis I mission design and the lunar month.