1. I. Şakraker, C.O. Asma, R. Torras-Nadal, O. Chazot 20.06.2013 IPPW-10 San Jose, CA, USA Ground Testing of In-Flight Experiments of Re-Entry CubeSat QARMAN

2. QARMAN: Real Flight Testbed QubeSat for Aerothermodynamic Research and Measurements on AblatioN Platform: Triple CubeSat with Ablative TPS Mission: Atmospheric Entry Technology Demonstrator, Starting Altitude of 350 km Launch: 2015 with QB50 Network Why a Re-Entry “CubeSat”? → Standardized small platform eliminates the only drawback: High Costs → Standard launch adaptors leading to highly flexible launch opportunities → If successful, it will be an affordable test platform for ablators, ceramics, sensors, trajectories, in-flight demonstrations, de- orbiting systems etc. 2

3. 3 Free Stream Measurements Cold Wall Heat Flux Static&Total Pressure Spectrometer Ablation Measurements Pyrometer : Temperature Radiometer : Temperature as f(ε) Spectrometer : Species Detection High Speed Camera Infrared Camera Thermocouples VKI Plasmatron Measurement Techniques Courtesy: Helber

4. VKI Plasmatron 4 Stagnation Point Heating by Fay&Riddell, 1958 Local Heat Transfer Simulation Thermo-chemical equilibrium at stagnation point: → Subsonic plasma Full simulation of stagnation region

5. 5 Velocity Gradient, β, Duplication β Definition differs in Subsonic and Hypersonic due to BL model Unique to Trajectory and Vehicle Geometry QARMAN Stagnation Line at 50 km Stagnation Line at Plasmatron

6. 6 Velocity Gradient, β, Duplication Conventional Method: Effective Radius Modified Newtonian Theory Spherical BodiesBlunt Bodies… ? Ref: Lees1957

7. 7 Velocity Gradient of Blunt Bodies Boison & Curtiss 1958  Geometries having bluntness parameter x*/r* less than 0.25 no longer obey MNT! x*/r* Velocity Gradient, β, Duplication

8. 8 Iterative Approach for Test Model Geometry Determination 1- Pick a β 2- Determine the Reff Hypersonic (i.e MNT) 3- Pass from Reff Hypersonic to Subsonic by matching the heat flux equation 1- Take the ICP Computation and calculate NDPs 2- Momentum equation provides the Reff Subsonic for ground facility Extract R model Velocity Gradient, β, Duplication @ 66 km Rm=5.8 mm @ 60 km Rm=94 mm

9. QARMAN Flight Challenges 9 Flight Aerothermodynamic Database  CFD++

10. QARMAN: Sensor Accommodation 10

11. Experimental Payloads Overview PayloadObjectiveSensor XPL01TPS EfficiencyTemperature XPL02TPS & EnvironmentPressure XPL03StabilityPressure XPL04Shear Force, TransitionPressure, Skin Friction XPL05Off-Stagnation Temperature Temperature XPL06Aerothermodynamic Environment and Radiation Spectrometer 11

12. Aerothermodynamic Instrumentation 12 Investigated Challenge Parameter to measureSensorPhase TPS EfficiencyTemperature Distribution12 x TC3 TPS & EnvironmentPressure2 x Pressure Sensor3 StabilityPressure2 x Pressure Sensor2b Rarified Flow ConditionsLow Pressure / Vacuum1 x Vacuum Sensor 2a 2b Shear Force, Laminar to Turbulence Transition Skin Friction4 x Preston Tube 2b 3 Off-Stagnation Temperature Evolution Temperature10 x TC 2b 3 ATD EnvironmentSpecies1 x Spectrometer3 Intensity1 x Photodiode3 Phase 3 Budgets Total Mass: 319 g Total Energy Consumption: 0.556 W h Total Data Size: 21.57 KB

13. 13 QARMAN TPS Selection Campaign - Enthalpy measured by REDES [MJ/kg] Samples: QARMAN 1/2 Scale Materials: Cork P50 and ASTERM Objectives: 1- Monitor insulation properties 2- Monitor corner behavior Conditions: Constant Pressure 100 mbar Target Heat Fluxes: 708; 1250; 1500; 1640 kW/m 2 Total duration 80 s (20 s at each heat flux) QARMAN TPS Selection Campaign

14. 14 QARMAN TPS Selection Campaign - Enthalpy measured by REDES [MJ/kg] Campaign Completed – 16 May 2013 Measurement Techniques: Free Stream Measurements - Water cooled calorimeter - Pitot Probe and Static Pressure Sensor - Spectrometer Sample Measurements - Radiometer - Pyrometer - High Speed Camera - Thermocouples, 3 Type E + 1 Type K - 3 Spectrometers aligned from wall stagnation outward QARMAN TPS Selection Campaign

15. 15 High Speed Camera → Recession & Swelling ASTERMCork P50 Stag. Point: +1mm Corner: -7.4 mm Stag. Point: -3.2mm Corner: -6.6 mm QARMAN TPS Selection Campaign

16. 16 QARMAN TPS Selection Campaign ASTERMCork P50 Pyrometer Radiometer Thermocouples ASTERM Cork T surface = 2400 K T surface = 2500 K Spectroscopic Characterization, Talk by B. Helber this afternoon

17. Payloads: XPL01 TPS Efficiency & Heating 2 Thermal Plugs Measurement Chain Summary 17

18. Thermal Plugs 18 60° 14mm 50mm 6 Thermocouples at 2.5, 5, 10, 20, 30, 40 mm At 60° apart 2 thermocouple per side trail TC Type K or R inserted in U-shape Payloads: XPL01 TPS Efficiency & Heating

19. 19 XPL02: Stagnation Region & TPS Pressure ExoMars Concept Diagonally 2 pressure taps CFD: QARMAN @ 66km Courtesy: G. Pinaud

20. Stability determination (max. angles and rates) in-flight with Pressure sensors Accelerometers Gyroscopes Strain gauges AeroSDS -> XPL03 20 Wall temperature T [K] 6-DoF simulations for osciallation frequency CFD simulations for surface pressure, temperature and force determination

21. Payloads: XPL06 Radiation Study: Spectrometer Spectrometer Spectrometer support structure TPS bonding structure TPS Photometer Light splitter Optical path sleeve Staged optical path Measurement Setup 21 Presented by Bailet earlier today

22. Questions? isil.sakraker@vki.ac.be 22 QARMAN project is partially supported by the European Community Framework Programme 7, Grant Agreement no. 284427 in the framework of QB50 Project. QARMAN Team: Thorsten Scholz, Gilles Bailet, Isil Sakraker, Cem O. Asma