In an orbital environment, outgassed, offgassed, ambient, and vented molecular species can cause spacecraft performance degradation by direct impingement or by scattering with each other in the gas phase before and after reemitting from the spacecraft surfaces. This can cause detrimental conditions for the spacecraft surfaces and sensors who view through this cloud. Likewise particulates released by the spacecraft, or nearby systems, can deposit on surfaces, intercept optical lines-of-sight or recontact the vehicle later on in the mission, causing surface damage. This paper presents two models that have improved capability over previous similar models. The integrated spacecraft environments model (ISEM) can be used to predict the transport of spacecraft generated molecular species as they collisionally interact with each other and the ambient molecular environment. An ISEM analysis produces a three dimensional mapping of molecular density and velocity by molecular species, within a modeling volume defined by the user. This model is the next generation of the SPACE and Molflux contamination models and was developed through NASA funding. The orbital particulate trajectory model (OPT) can be used to predict the particulate locations of released particulates as a function of time relative to the spacecraft coordinate system as well as an Earth coordinate system. In this paper the capabilities, applications, validation, and availability of the (ISEM) and the (OPT) model are discussed.
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