European sounding rocket experiment on hypersonic deployable re-entry demonstrator

The Italian and European Space Agencies (ASI and ESA) are supporting the IRENE research programme, developed in Campania region (South of Italy) by a cluster of industries, research organizations and universities, on a low-cost deployable re-entry system, to enable future space missions, including payloads return on Earth from the ISS and/or recoverable scientific experiments in Low Earth Orbit (LEO). Deployable systems could be also applied to future robotic exploration missions or, in perspective, to future manned space systems, requiring planet atmosphere entry or Earth re-entry. They can be accommodated in the selected launcher in folded configuration (optimizing the available volume) and, when foreseen by the mission profile, the aerobrake can be deployed in order to increase the surface exposed to the hypersonic flow and therefore to reduce the ballistic parameter. In this way the reentry trajectory of the ballistic capsule is characterized by deceleration at relatively high altitudes, by relatively low heat fluxes, mechanical loads and final descent velocity. This technology offers also an interesting potential for aerobraking/aerocapture and for de-orbiting without the need of a dedicated propulsive subsystem. The deployable surface can be modulated for the aerodynamic control of the de-orbit trajectory in order to correctly target the capsule towards the selected landing site. The dramatic reduction of the ballistic coefficient shall even provide the opportunity to aerocapture and land very large payloads also on planets surrounded by thin atmospheres. This paper summarizes the results of these activities, including mission analyses, aerodynamic studies, prediction of thermal and mechanical loads, thermal and structural analyses. A technology “ground demonstrator” of the umbrella-like structure has been developed to test on ground the most critical functions (kinematics of the deployment system, configuration of the flexible structure, efficiency of the selected actuators, etc.) and the mechanical stresses expected in flight.