EVD: A Flight Demonstrator for the Mars Sample Return Earth Reentry Capsule

The Mars Sample Return (MSR) mission currentl y under consideration as a "Flagship" Aurora/Exploration activity at ESA, has been proposed with a companion "Arrow" mission for risk mitigation in the area of Earth Hypervelocity Entry. The mission has been dubbed EVD (Entry Vehicle Demonstrator) and aims at demonstrating the technologies and system capabilities required for ballistic hypervelocity entry on Earth, so far unproven in ESA member states. Also relevant for EVD is the demonstration of the capability to return a Sample Container in a condition c ompatible with the planetary protection requirements enforced for MSR. I. Introduction mong the missions envisaged in the frame of ESA's Aurora/Exploration Programme, the "Flagship" Mars Sample Return features a hypervelocity entry of the Earth Reentry Capsule (ERC), with stringent constraints concerning sample recovery and planetary protection issues. The novelty of such a non -destructive re -entry for ESA Member States, has prompted the need for an "Arrow" mission demonstration of that capability. Arro w missions are intended as technology missions, with a short development time and low cost. Appropriately dubbed "Entry Vehicle Demonstrator", the subject arrow mission has been studied in the frame of two parallel Pre -Phase A contracts and associated ride rs for consolidation. Of paramount importance for the MSR mission, the severe mass constraints associated to the Earth Return Capsule, due to carry the martian soil samples, would have to be demonstrated in the frame of EVD. Indeed, the very feasibility o f the MSR mission requires a sample return capsule mass of less than 80 kg, according to the most recent estimates. The accommodation of such a stringent mass requirement along with the demanding aeroshape and TPS (Thermal Protection System) aspects furthe r substantiate the need for a precursor EVD experiment. The current schedule for the MSR mission would also allow for the implementation of EVD in a cooperative frame. In this paper, hypervelocity entry is considered as resulting from Earth hyperbolic traj ectories, with entry interface relative velocities in excess of 12 km/s and representative of the speeds encountered by MSR Earth Return Capsule. The EVD activities at ESA have now been completed, reaching Pre -Phase A status, but with a maturity significan tly higher than that usually attributed to that phase. The study has been implemented by means of two parallel contracts awarded to competing teams and spans the initial pre -Phase A study and a rider for convergence on essential concept definition paramete rs (9 months and 4 months duration, respectively). The two teams selected for the study are, on one hand, a consortium led by EADS -ST with OHB and Plansee, and, on the other hand, SSTL (Prime) with FGE and Vorticity.