Mars Science Laboratory Roll Control System Thruster Seals

During atmospheric entry into Mars, Mars science laboratory (MSL) requires a dynamic seal around the roll control system (RCS) thrusters. The RCS thrusters are mounted on the descent stage which is on the inside of Backshell. The thrusters protrude slightly through cutouts in the Backshell. The seal is mounted on the Backshell and interfaces with an aerodynamic shroud that surrounds the thruster nozzle ends. The seal´s main requirement is to aid in blocking the aero-thermal heating during atmospheric entry from entering into the Backshell. The seal must also be able to take the heat loading that is subjected by the thruster themselves, in addition to being a dynamic seal as there are relative deflections on the order of 6.5 mm (designed to handle 15 mm) across the sealing interface. The seal design is comprised of thin titanium shim stock that is arranged in a staggered-shingled blade configuration that flexes, absorbs relative motion, and seals gaps between blades. Analysis and testing was performed to validate the design´s capability to perform as required during atmospheric entry into Mars.