  The Double Asteroid Redirection Test (DART) spacecraft will impact into the
asteroid Dimorphos on September 26, 2022 as a test of the kinetic impactor
technique for planetary defense. The efficiency of the deflection following a
kinetic impactor can be represented using the momentum enhancement factor,
Beta, which is dependent on factors such as impact geometry and the specific
target material properties. Currently, very little is known about Dimorphos and
its material properties that introduces uncertainty in the results of the
deflection efficiency observables, including crater formation, ejecta
distribution, and Beta. The DART Impact Modeling Working Group (IWG) is
responsible for using impact simulations to better understand the results of
the DART impact. Pre-impact simulation studies also provide considerable
insight into how different properties and impact scenarios affect momentum
enhancement following a kinetic impact. This insight provides a basis for
predicting the effects of the DART impact and the first understanding of how to
interpret results following the encounter. Following the DART impact, the
knowledge gained from these studies will inform the initial simulations that
will recreate the impact conditions, including providing estimates for
potential material properties of Dimorphos and Beta resulting from DARTs
impact. This paper summarizes, at a high level, what has been learned from the
IWG simulations and experiments in preparation for the DART impact. While
unknown, estimates for reasonable potential material properties of Dimorphos
provide predictions for Beta of 1-5, depending on end-member cases in the
strength regime.
