ReFEx after separation on its suborbital trajectory in space
DLR (CC BY-NC-ND 3.0).
ReFEx Re-Entry Configuration
ReFEx – the internals
The Reusability Flight Experiment (ReFEx) is being developed by DLR to provide flight and design data on, as well as operational experience with, aerodynamically controlled RLV stages. As such ReFEx will be a small technology demonstrator and is slated for launch in 2024. 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 flight.
ReFEx is about 2.7 m in length, has a wingspan of about 1.1 m and has a mass of approx. 450kg. It is controlled by a nitrogen cold gas reaction system (RCS) while outside the atmosphere and shall transition toaerodynamic control surfaces (canards and rudder) when atmospheric effects come into play. The maximum Mach number reached during the re-entry manoeuvre is about Mach 5.
Besides being able to fly an optimised trajectory (generated autonomously on-board) to reduce the thermal and mechanical loads, ReFEx shall demonstrate manoeuvrability by flying a turn of at least 30° with respect to the original heading measured from entry interface. The entry interface was placed at 60 km altitude for the purposes of this experiment, as the effects of the atmosphere become significant at this altitude for the foreseen trajectory.
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 an optimised 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 Fiber
Optic Sensors (FOS) and Flush Air Data System (FADS)
Institute of Aerodynamics and Flow Technology (AS)
Department of Supersonic and Hypersonic Technology (HYP)
Department Spacecraft (RFZ-BS)
Department Spacecraft (RFZ-GÖ)
The departments of the Institute of Aerodynamics and Flow Technology involved in the ReFEx project provide the aerodynamic expertise. This includes the initial aerodynamic design of the vehicle, the generation of the aerodynamic database, the verification via wind-tunnel testing, the provision of the aerodynamic experiments and sensors on board as well as the post flight analysis of the data gained through the flight experiment.
Institute of Structures and Design (BT)
Space System Integration (RSI)
The department of the Institute of Structures and Design involved in ReFEx project provides the expertise regarding the design, the fabrication, the verification and testing of the Re-Entry Segment structure. This includes the fuselage, the wings, the aerodynamic control surfaces (canards and rudder), the wing folding mechanisms, the separation systems for fairing and Re-Entry Segment. Furthermore the Launch Support Structures such as the payload adapter and fairing are provided.
Institute of Flight Systems (FT)
Department Safety Critical Systems & Systems Engineering (SSY)
The department SSY provides the actuators for the aerodynamic control surfaces (canards, rudder) and the corresponding actuator control electronics as well as the guidance and control computer (GCC). This includes the design, the manufacturing and testing of the actuators, the electronics as well as the guidance and control computer (GCC).
Institute of Space Operations and Astronaut Training (RB)
Mobile Rocket Base – MORABA (MRB)
Space Flight Technology (RFT)
The departments of Space Operations and Astronaut training involved in ReFEx project provide the Launch Segment (VSB-30), the launch campaign support (including logistics), the data handling system and telemetry / telecommand (optional) systems and corresponding support. Furthermore two redundant GPS receivers utilized within the hybrid navigation system are provided by the department of Space Flight Technology.
Institute of Space Systems (RY)
Systems Engineering and Project Office (SPB)
System Analysis Space Segment (SRS)
Avionic Systems (AVS)
Navigation and Control Systems (GNC)
Mechanics and Thermal Systems (MTS)
Product Assurance (QPS)
Space Launcher System Analysis (SRT)
Transport and Propulsion Systems (TAS)
The departments of the Institute of Space Systems provide the overall project management (SPB) and systems engineering (SPB), the AIT (Assembly Integration and Testing) campaign on a system level (SPB) as well as the product assurance (QPS) of the ReFEx project. From a modelling and analysis standpoint it provides the initial system studies for the project, as well as studies of possible future RLVs, taking the results of the entire project into account (SRT). Hardware provided includes the hybrid navigation system (GNC), the power system (AVS) and the cold gas reaction system (TAS).Furthermore, testing facilities and testing support are provided (MTS).
Institute for Software Technology (SC)
Software for Space Systems and Interactive Visualization (SRV)
The department of the Institute for Software Technology involved in ReFEx project provides the base software for the HNS and the GCC including the driver software for the various sensors and actuators of these subsystems.
Institute of System Dynamics and Control (SR)
Space System Dynamics (SR-RFS)
The department Space System Dynamics of the Institute of System Dynamics and Control involved in ReFEx project provide the dynamical flight model software for the flight controller.