Supersonic Inflatable Aerodynamic Decelerators For Use on Future Robotic Missions to Mars

The 2009 Mars Science Laboratory mission is being designed to place an 850 kg rover on the surface of Mars at an altitude of at least one kilometer [1]. This is being accomplished using the largest aeroshell and supersonic parachute ever flown on a Mars mission. Future missions seeking to place more massive payloads on the surface will be constrained by aeroshell size and deployment limitations of supersonic parachutes [2],[3]. Inflatable aerodynamic decelerators (IADs) represent a technology path that can relax those constraints and provide a sizeable increase in landed mass. This mass increase results from improved aerodynamic characteristics that allow IADs to be deployed at higher Mach numbers and dynamic pressures than can be achieved by current supersonic parachute technology. During the late 1960's and early 1970's preliminary development work on IADs was performed. This included initial theoretical shape and structural analysis for a variety of configurations as well as wind tunnel and atmospheric flight tests for a particular configuration, the Attached Inflatable Decelerator (AID). More recently, the Program to Advance Inflatable Decelerators for Atmospheric Entry (PAI-DAE) has been working to mature a second configuration, the supersonic tension cone decelerator, for use during atmospheric entry. This paper presents an analysis of the potential advantages of using a supersonic IAD on a proposed 2016 Mars mission. Conclusions drawn are applicable to both the Astrobiology Field Laboratory and Mars Sample Return mission concepts. Two IAD configurations, the AID and tension cone, are sized and traded against their system-level performance impact. Analysis includes preliminary aerodynamic drag estimates for the different configurations, trajectory advantages provided by the IADs, and preliminary geometric and mass estimates for the IAD subsystems. Entry systems utilizing IADs are compared against a traditional parachute system as well as a system employing an IAD in the supersonic regime and a parachute in the subsonic regime. Key sensitivities in IAD design are included to highlight areas of importance in future technology development programs.