MSL heatshield development: From failure to success

Mars Science Laboratory is a scientific mission that places a 900 kg rover with 10 science instruments on the surface of Mars. A key component for landing on the surface of Mars is the aeroshell, which decelerates the entry vehicle to just 1% of its initial kinetic energy at atmospheric entry. The forward portion of the aeroshell is the heatshield which must be designed to withstand the pressure, heating, and shear stresses it experiences during the atmospheric deceleration process. The original exterior material chosen for the heatshield, SLA-561V, was the material used on all previous Mars aeroshells but required new qualification testing. Unfortunately, the material failed the more extreme environment 3 months after the aeroshell and project Critical Design Reviews. A rapid decision was required to switch to another material under test by the Orion program call Phenolic Impregnated Carbon Ablator (PICA). With 18 months left to design, fabricate, test, and deliver this new heatshield for the MSL 2009 launch opportunity, the PICA heatshield team had to rapidly respond to the challenge and work in a manner that ensured success. This paper discusses the lessons learned from the original SLA-561V design implementation and the process used to ensure the success of the PICA design implementation.