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The DART spacecraft will impact Didymos's secondary, Dimorphos, at the end of2022 and cause a change in the orbital period of the secondary. For simplicity,most previous numerical simulations of the impact used a spherical projectilegeometry to model the DART spacecraft. To investigate the effects ofalternative, simple projectile geometries on the DART impact outcome we usedthe iSALE shock physics code in two and thee-dimensions to model verticalimpacts of projectiles with a mass and speed equivalent to the nominal DARTimpact, into porous basalt targets. We found that the simple projectilegeometries investigated here have minimal effects on the crater morphology andmomentum enhancement. Projectile geometries modelled in two-dimensions thathave similar surface areas at the point of impact, affect the crater radius andthe crater volume by less than 5%. In the case of a more extreme projectilegeometry (i.e., a rod, modelled in three-dimensions), the crater was ellipticaland 50% shallower compared to the crater produced by a spherical projectile ofthe same momentum. The momentum enhancement factor in these test cases,commonly referred to as beta, was within 7% for the 2D simulations and within10% for the 3D simulations, of the value obtained for a uniform sphericalprojectile. The most prominent effects of projectile geometry are seen in theejection velocity as a function of launch position and ejection angle of thefast ejecta that resides in the so-called `coupling zone'. These results willinform the LICIACube ejecta cone analysis.

Influence of the projectile geometry on the momentum transfer from a kinetic impactor and implications for the DART mission