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

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 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

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

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 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, 66 km Rm= km Rm=94 mm

QARMAN Flight Challenges 9 Flight Aerothermodynamic Database  CFD++

QARMAN: Sensor Accommodation 10

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

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: W h Total Data Size: KB

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 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 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 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

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

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

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

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

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