Abstract Hardware released during spacecraft entry can generate hypervelocity impacts that provide unique constraints on planetary subsurface properties. During NASA’s Perseverance descent, two tungsten cruise ballast mass devices (CBMD) and fragments of the cruise stage formed meter‐scale craters north‐west of Jezero crater, in one of the sinuous valleys that converge into the Jezero delta. Using high‐resolution orbital images and trajectory predictions, we identify the two CBMD craters and use shock‐physics modeling to quantify local material strength. π ${uppi }$‐scaling relations overestimate crater diameters by an order of magnitude in this shallow‐angle, high‐density‐contrast regime between projectile and target, whereas simulations reproduce the observed crater sizes for target cohesion of 7±1.5 $7pm 1.5$ kPa consistent with regolith. These results demonstrate that ballast mass impacts can serve as deliberate impact experiments. Future mission designs could intentionally leverage such impacts to probe shallow subsurface material properties on Mars and other planetary bodies.