AEROTHERMODYNAMIC ANALYSIS OF INNOVATIVE HYPERSONIC DEPLOYABLE REENTRY CAPSULES Raffaele Savino University of Naples Federico II
Objectives Show the main capabilities of deployable aero-brakes for Earth re-entry capsules Perform aerothermodynamic and mission analyses of such re-entry systems Assess some feasible missions offered by the system Study and design technological demonstrators for the experimental verification of the system effectiveness and functionality along different sub-orbital flight profiles
Introduction (1)
Thermal and mechanical loads
Orbital missions
Sub-orbital missions
TPS materials
Re-entry from LEO CubeSats Contrast the phenomenon of Space debris Match the 25 years requirement for orbital decay Enable orbit insertion at larger altitudes Possibility to recover payloads and data Reduce costs reusing hardware and subsystems Perform post-flight inspections and experimentations
Re-entry from LEO De-orbit trajectories Standard CubeSat CubeSat with aerobraking system Possibility to increase the orbit altitude for orbital decay Significant reduction of the orbital decay lifetime
Re-entry from LEO Air-launchable system The orbital injection can be performed at relatively low altitude to reduce size, mass and cost of optical equipment, optimize the spatial resolution on the ground Many kind of orbits can be selected for efficient Earth observations or for other objectives, depending on the specific mission requirement, due to the flexibility offered by air launch The deployable aerobrake can allow the capsule to perform efficient manoeuvres in a relatively short time, with low risks and avoiding any propulsive boost
Re-entry from LEO Aerodynamic control of de-orbit trajectories The reference surface modulation can be exploited to cope with the off-nominal conditions along the de-orbit trajectory (like, in this case, the air density disturbances) to correctly target the capsule towards the selected landing site
Re-entry from LEO De-orbit and re-entry trajectories H = 63.5 km, M = 11.0 H = 76.4 km, M = 20.7
Re-entry from LEO CFD and DSMC Aerothermodynamic analyses H [km] M [-] Re [-] 76.4 20.7 14165
Re-entry from LEO Aerodynamic stability H [km] M [-] Re [-] 50.0 3.30 65096 Nominal re-entry attitude CG=A CG=B CG=C dcmz/dα [deg-1] -4.5 10-3 -3.3 10-3 -2.1 10-3 CG=D CG=E -1.0 10-2 3.7 10-3
Technology demonstrator Technology demonstrator for Maxus rocket (IRENE, ALI) Compatibility with Maxus interstage Total mass less than or equal to 15 kg Ballistic coefficient lower than 20 kg/m2 Automatic system for TPS deployment TPS able to withstand heat fluxes in the order of 300-350 kw/m2 Structure able to withstand mechanical loads in the launch phase & aerodynamic loads in the atmospheric re-entry
Technology demonstrator Technological demonstration mission
Technology demonstrator Suborbital re-entry trajectories H = 47.0 km, M = 9.00 H = 38.0 km, M = 6.50
Technology demonstrator CFD Aerothermodynamic analyses Air can be considered in chemical equilibrium, due to the relatively low energy profile Pressure [Pa] Temperature [K]
Technology demonstrator Technology demonstration mission for Rexus Launch from Kiruna within the Rexus fairing Ejection from the rocket fairing after the nosecone fairing ejection and before the rocket de-spinning Aerobrake deployment during descending parabola Telemetry retrieval of critical data Landing and recovery Main requirements Compatibility with Rexus payload fairing Total mass around 5 kg Automatic system for TPS deployment Structure able to withstand mechanical loads in the launch phase and aerodynamic loads during the atmospheric re-entry phase
Technology demonstrator Suborbital re-entry trajectories
Technology demonstrator CFD Aerodynamic analyses H [km] M [-] Re [-] 45.0 1.38 47647
Technology demonstrator CFD Aerodynamic analyses T0 T0+0.07 T0+0.04 T0+0.02 Frequency: 14 Hz Amplitude: p [Pa] CL [-] CD [-] CM [-] 80 0.020 0.015 0.040
Wind tunnel model
Conclusions Numerical models show the possibility to study different scenarios for orbital re-entry and for suborbital demonstrators A new method for the aerodynamic control of a variable geometry umbrella-like structure has been proposed Evaluation of the aerothermodynamic conditions linked to the TPS concept and materials identified Many results can be applied to future specific mission and system analyses and for the design of wind tunnel and flight drop tests