Hydrocode simulations of debris impacts on the secondary containment vessel during landing of the Mars Sample Return earth entry vehicle

NASA sample return missions must satisfy backward planetary protection requirements which include the need to assure robust containment. The Earth Entry System architecture that was in place in December 2023 is passive after release from the carrier spacecraft; the entry trajectory is ballistic, and no parachute is used. At release, the system is targeted to land on soft soil within the Utah Test and Training Range, and displacement of the soil should absorb much of the impact energy. In the unlikely event that the vehicle impacts a hard surface, or a damaged vehicle lands at higher-than-predicted velocity, the heat shield may break and potentially cause debris to impact the Secondary Containment Vessel which houses the samples. This paper describes a set of hydrocode simulations of potential debris items striking the Secondary Containment Vessel, to show that the 2023 design can withstand such impacts and the risk of loss of containment is negligible except at impact velocities in excess of 200 m/s.