AEROTHERMODYNAMIC ANALYSIS OF INNOVATIVE HYPERSONIC DEPLOYABLE

REENTRY CAPSULES

Raffaele SavinoUniversity 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 = 76.4 km, M∞ = 20.7

H = 63.5 km, M∞ = 11.0

Re-entry from LEO

• CFD and DSMC Aerothermodynamic analyses

H [km] M∞ [-] Re∞ [-]

76.4 20.7 14165

Re-entry from LEO

• Aerodynamic stability

CG=A CG=B CG=C CG=D CG=E

dCmz/dα [deg-1] -4.5∙10-3 -3.3∙10-3 -2.1∙10-3 -1.0∙10-2 3.7∙10-3

Nominal re-entry attitude

H [km] M∞ [-] Re∞ [-]

50.0 3.30 65096

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 phase

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

Pressure [Pa]

Temperature [K]

• Air can be considered in chemical equilibrium, due to the relatively low energy profile

Technology demonstrator

• Technology demonstration mission for Rexus

• 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

• 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

Technology demonstrator

• Suborbital re-entry trajectories

Technology demonstrator

• CFD Aerodynamic analysesH [km] M∞ [-] Re∞ [-]

45.0 1.38 47647

Technology demonstrator

• CFD Aerodynamic analyses

• Frequency: 14 Hz

T0 T0+0.02T0+0.04

T0+0.07p [Pa] CL [-] CD [-] CM [-]≈ 80 ≈ 0.020 ≈ 0.015 ≈ 0.040

• Amplitude:

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