Flight Experiment of the Capsule with the Deployable Flexible Aeroshell

1. Flight Experiment of the Capsule with the Deployable Flexible Aeroshell Using a Large Scientific Balloon Kazuhiko Yamada, Daisuke Akita, Eiiji Sato,Kojiro Suzuki (University of Tokyo) Yuuki Tsutusmi, Kazuhiko Wakatuki (Tokai University) Tomohiro Narumi, Akira Sakurai (Kyushu University) Takashi Abe, Yukihiko Matsusaka (ISAS/JAXA) 56th International Astronautical Congree In Fukuoka JAPAN

2. CONTENTS • Background Membrane Aeroshell Concept • Outline of flight test • Flight model Configuration Sensors • Results Behavior of membrane aeroshell Flight trajectory Aerodynamic Characteristics • Conclusions

3. Background New Concept of Atmospheric-entry system Conventional Flexible Aeroshell Withstand high aerodynamic heating Avoid high aerodynamic heating C/C material or Ablator Large and Light Aeroshell And Soft Landing Parachute System for Soft Landing

4. Outline of project Drop flight test of actual size model of flexible membrane aeroshell using a Balloon from at a altitude of 39km Separation Ascending Free Flight Mach number : 0.9 Dynamic pressure : 0.84kPa Launching

5. Objectives • Development of a actual scale capsule-type vehicle with a deployable membrane aeroshell • Demonstration of the capability of the deployable membrane structure and the stable flight • Obtaining the aerodynamic characteristics and the behavior of the aeroshell in transonic and subsonic flow regimes

6. Flight Model Outer Frame • Dodecagonal configuration • Material : 12 Aluminum hollow pipes • Weight : 2.6 kg • Carpenter tape hinge deployment mechanism Membrane Aeroshell • Flare configuration • Material : ZYLON • Weight : 0.6 kg • Maximum Diameter 150cm • Grid pattern was printed Capsule • Hemispheric configuration • Material : Iron • Weight : 102 kg • Diameter : 60cm • All device were installed

7. Sensors • CCD camera • Fish eye lens • Acceleration Sensors • Angular Velocity Sensors • Geomagnetism Sensors • Pressure Transducer • Piezo Film • Thermo couple • GPS Attitude and motion Trajectory Behavior of Aeroshell Environmental of Flight All data were transferred to ground station by telemetry system

8. Deployment Demonstration Deployed Configuration At Ground Test Folded Configuration

9. Balloon flight 1. Mount the flight model 2. Turn on all the sensors 3. Launching balloon 4. Separation of the flight from an altitude of 40 km 5. Data transfer to the ground during flight 6. Splash down （No recovery ） 7. Balloon and gondola is recoveries.

10. Results CCD image • Oscillation of the membrane aeroshell • Deformation of the membrane aeroshell • Attitude and rotation of the capsule Horizontal Trajectory Vertical Trajectory • Deceleration performance

11. CCD IMAGE Two CCD cameras are equipped 気球本体 ゴンドラ Camera １ カッター 外枠 紐 膜面 Camera ２ 魚眼レンズ カプセル

12. Membrane Oscillations FFT analysis Time variation of frequency spectrum Output of piezo film 10Hz 4Hz Membrane Aeroshell oscillated at a frequency of 4Hz and 10Hz

13. Membrane Deformation determiened from CCD Image through fish-eye lens and assumption that membrane does not stretch In Flight Unloaded Membrane aeroshell deformed to concave shape due to aerodynamic force

14. Attitude and Rotation Track of Sun in the CCD View Angular Velocity around body axis →Capsule did not inclined → Capsule rotated around body axis Vehicle kept a vertical attitude with rotation during flight.

15. Horizontal Trajectory Horizontal Trajectory Wind and Horizontal Motion →Horizontal Motion is synchronized with the wind →Capsule traveled in 6km horizontally Vehicle dropped with zero angle of attack.

16. Vertical Trajectory ~ Comparison with simulation History of Vertical Acceleration History of Vertical Velocity and Altitude →Flight data is in good agreement with trajectory Simulation

17. Aerodynamic Characteristics Mach Number vs Drag Coefficient Drag Coefficient S=1.617m2 m=106kg g=9.8m/s2 Comparison with Wind Tunnel test Plot the flight data from 5km to 35 km →Flight data is good agreement with Wind tunnel data The flare-type membrane aeroshell has a reasonable deceleration performance in free flight condition as we expected at wind tunnel test.

18. Conclusions The flight test of the capsule with flare-type membrane aeroshell was carried out using a Large scientific Balloon. In flight test, The flight model kept stable and vertical attitude The flight model dropped with a zero angle of attack The 4Hz and 10Hz oscillations were induced in both transonic and subsonic regime The flight path and drag coefficient is in good agreement with the Trajectory analysis and wind tunnel test. It is demonstrated the flare-type membrane aeroshell has a good deceleration performance

19. Wind Tunnel Test Low speed Wind Tunnel Test Drag Coefficient vs Angle of Attack Concave shape Tack-like Wrinkle Transonic Wind Tunnel Test

20. Separation Demonstration Set up Main rope Cutter Separation

21. Advantages Reference Case （Small sounding rocket ） Mass = 50kg Altitude = 200km Diameter = 20cm Velocity =1000m/s Dramatic Reduction of the Surface temperature