NASA’s Double Asteroid Redirection Test (DART) mission will impact its target asteroid, Dimorphos, at an
oblique angle that will not be known prior to the impact. We computed iSALE-3D simulations of DARTlike impacts on asteroid surfaces at different impact angles and found that the vertical momentum transfer
efficiency, 𝛽, is similar for different impact angles, however, the imparted momentum is reduced as the impact
angle decreases. It is expected that the momentum imparted from a 45◦
impact is reduced by up to 50%
compared to a vertical impact. The direction of the ejected momentum is not normal to the surface, however
it is observed to ‘straighten up’ with crater growth. iSALE-2D simulations of vertical impacts provide context
for the iSALE-3D simulation results and show that the ejection angle varies with both target properties and
with crater growth. While the ejection angle is relatively insensitive to the target porosity, it varies by up
to 30◦ with target coefficient of internal friction. The simulation results presented in this paper can help
constrain target properties from the DART crater ejecta cone, which will be imaged by the LICIACube. The
results presented here represent the basis for an empirical scaling relationship for oblique impacts and can
be used as a framework to determine an analytical approximation of the vertical component of the ejecta
momentum, 𝛽 − 1, given known target properties.