An update of the upcoming DLR reusability flight experiment - REFEX

During the last International Aeronautical Congress (IAC) in Adelaide, the Reusability Flight Experiment (ReFEx), a technology demonstrator for Reusable Launch Vehicle (RLV) technologies, was presented for the first time. ReFEx is being developed by DLR (German Aerospace Center) to provide flight and design data on, as well as operational experience with, a winged fly-back booster concept and is slated for launch in 2021. The experiment will be launched on a VSB-30 sounding rocket to altitudes and velocities similar to a first staging event and will then attempt a return flight along a trajectory comparable to a returning winged first stage RLV, transitioning from hypersonic speeds down to subsonic velocity. The key technologies demonstrated in this vehicle are, amongst others: aerodynamic design of a vehicle capable of stable flight through many flow regimes, guidance, navigation and control (GNC) capable of on-board generation of a feasible, quasi-optimal trajectory, the seamless transition between extra- and intra-atmospheric flight controls and health monitoring of the vehicle status during flight using advanced sensors such as FOS (Fibre Optic Sensors) and FADS (Flush Air Data System). This paper will give an update of the current system design and shed some light on the current efforts to provide a safe flight with an experimental guided vehicle.