Deployment and Flight Test of Inflatable Membrane Aeroshell using Large Scientific Balloon

Transcription

1 1 Deployment and Flight Test of Inflatable Membrane Aeroshell using Large Scientific Balloon Kazuhiko Yamada, Takashi Abe (JAXA/ISAS) Kojiro Suzuki, Naohiko Honma, Yasunori Nagata, Masashi Koyama (The University of Tokyo) Daisuke Abe, Yusuke Kimura, A. Koichi Hayashi (Aoyama Gakuin University) Hitoshi Makino (Tokai University) Daisuke Akita (Tokyo Institute of Technology)

2 CONTENTS 2 Background Membrane aeroshell for atmospheric-entry capsule (MAAC) Advantage and key technology. Inflatable aeroshell flight test using balloon (Mini MAAC) Objectives. Experimental vehicle. Flight operation. Results. Conclusions

3 3 Background HAYABUSA capsule returned to the earth with success. From now on, even more sample return missions and planetary entry missions will be proposed. Withstand Aerodynamic heating We weed innovation of atmospheric-entry system for frequent space transportation between space and planet surface. One of the candidates is flexible aeroshell system Avoid Aerodynamic heating Large and light aeroshell is deployed in the space before reentry Flexible aeroshell can be packed in launching and operating in space. Vehicle re-enters into atmosphere with low aerodynamic heating and make soft landing without a parachute Flare-type membrane aeroshell supported by inflatable torus.

4 Advantage and key technology <Advantages of flexible aeroshell> Significant reduction of aerodynamic heating during reentry. Vehicle with large and light aeroshell can decelerate at high altitude where the atmospheric density is very low. Soft landing without additional parachute system or retro jet. Large and light aeroshell also works to reduce terminal velocity same as conventional parachute before landing. <Key technologies of flexible aeroshell> 4 1) To understand aerodynamic characteristics in whole range of Mach number 2) To develop and evaluate flexible material especially thermal durability 3) To develop a large but low-mass flexible aeroshell utilizing inflatable structure Inflatable torus Thin membrane Capsule (payload) Demonstration and investigate on inflatable aeroshell using a balloon

5 MINiature Inflatable MAAC experiment (MINI-MAAC) <Objectives> To demonstrate deployment and free flight of flare-type aeroshell supported by inflatable torus which is one of the next generation reentry system. To demonstrate the aeroshell deployment in vacuum condition in the air with remote control. To acquire the knowledge of the structural strength of inflatable torus against aerodynamic force during free flight condition. To obtain the aerodynamic characteristics of low-ballistic-coefficient vehicle in subsonic regime in free flight condition. 5 Launch Free drop All flight data is transmitted to ground station. Deployment and Separation Aeroshell is packed Ascend at ALT=25km Vehicle separation from gondola after aeroshell deployment. We does not request recover of experimental vehicle

6 Overview of Experimental System 6 Flight configuration <Gas injection device>

7 Experimental flight vehicle Capsule Packed aeroshell Deployed aeroshell 7 Total mass : 3.375kg All of device including sensor, telemetry, transmitter and battery is in capsule. Measurement item: Image of aeroshell, Ambient pressure, Inflatable pressure, Position by GPS, Accelerator, Angle velocity and so on Flare part was made of Nylon cloth. Inflatable torus was made of Nylon cloth coated by Urethane rubber.

8 Deployed configuration of aeroshell Before flight, deployment rehearsal was carried out in ambient pressure at sea level (=100kPa) with remote command and gas injection devices. 8 Deployment Gas injection Remote command 60kPa X 2 (Inflatable pressure = 120kPaA, 20kPaG) The aeroshell was deformed into saddle shape due to the out-of-plane buckling of inflatable torus.

9 Flight operation This experiment was carried out at TARF in 25 th August, Just before launch User s room Successful launch and ascend.

10 Results of MINI-MAAC 10 All of test sequence was carried out as planned and the flight test was very successful and fruitful. We acquired a lot of information and technology for flare-type inflatable aeroshell from MINI-MAAC experiment as following. Deployment technique in vacuum condition with remote control. Vehicle trajectory in horizontal direction compared with wind profile. Drag coefficient in low speed regime during free flight. Attitude of experimental vehicle during free flight. Data of structural strength of inflatable torus against aerodynamic force. These data in free flight condition are acquired just only flight test.

11 Deployment demonstration The inflatable aeroshell was deployed by injecting gas at altitude 25km. 11 Inflatable pressure history Gas injection finish Deployment was completed in 0.3 second after gas injection. Inflatable pressure reached the design value in 6 seconds after gas injection.

12 Separation from gondola Experimental vehicle was separated from gondola after deployment. From gondola 3-axis Acceleration history 12 From capsule Decelerate by aerodynamic force Capsule inclined

13 Horizontal Trajectory Horizontal trajectory was determined by GPS data 13 <Horizontal flight trajectory > <Comparison with wind profile> Horizontal velocity vector almost coincided with the wind velocity and direction. Experimental vehicle dropped with zero horizontal airspeed aerodynamic characteristics can be understood only by considering vertical motion.

14 Drag coefficient Drag coefficient during free flight was estimated from altitude history. 14 <Time history of altitude> <Comparison with simulation> Aeroshell was collapsed in 24 min after separation at altitude 4.0km as planned Drag coefficient of vehicle is constant in 1.0 though the ambient pressure changed significantly during free flight

15 Motion and attitude of Capsule Motion and attitude of capsule was measured by 3 axis acceleration sensors and angle velocity sensors around the body axis. 15 <Roll angle velocity history> <Capsule inclination history> Roll angle velocity Inclination Gravity force Capsule rotated around the body axis in 0.6Hz in maximum Capsule inclined against the gravity force in 15 degrees in maximum

16 Relation between aeroshell and capsule Aeroshell image captured through the fisheye lens Comparison between capsule inclination and aeroshell inclination 16 The angle between capsule body axis and center line of the aeroshell coincide with inclination of capsule against the gravity force. The aeroshell center line was almost same as the gravity force direction,although the capsule inclined against the gravity force.

17 Attitude and motion of vehicle during flight 17 <Schematic of attitude and motion> Capsule inclined against gravity force direction. Capsule rotated around the body axis. Aeroshell center line coincide with gravity force direction The capsule inclination and the angle velocity decreased gradually as the experimental vehicle descended. non-axisymmetric deformation into saddle shape due to out-of-plane buckling cause the unexpected motion and attitude.

18 Structural Strength of inflatable torus 18 The inner pressure in inflatable torus is purposely set to about 60kPaA. The aeroshell was collapsed during flight due to ambient pressure increase <Time history of inflatable pressure> <Aeroshell Image> Steady 300sec 900sec 1200sec Sudden collapse Separation Collapse 5.2kPa 1380sec 1440sec Aeroshell was collapsed when the differential pressure is 5.2kPa in free flight.

19 Comparison with simple analysis The most simple prediction for structural strength is derived, considering the balance between compressive force by external force and Tensile force by inner pressure. 19 In this assumption, aeroshell was collapsed in only local crippling mode F D 1 2 C AR r = 0.032m Θ in = 40 deg Θ out = 75 deg C AR = 0.97 F D = 33N cos in sin out 2 r p Threshold pressure = 2.1 kpa < 5.2 kpa : Flight data The aeroshell did not collapse in the crippling mode in the flight test, due to the considerable out-of-plane buckling deformation of the inflatable torus.

20 Conclusions of MINI-MAAC 20 Our group carried out Deployment and flight test of inflatable aeroshell using large scientific balloon in series of development of membrane aeroshell for new atmospheric-entry system This balloon test was very successful and fruitful. Our group achieved the following results in this test. 1) The aeroshell deployment by injecting gas to the inflatable torus was demonstrated through the remote command in the high altitude. 2) The flight trajectory, the vehicle attitude and motion and the aerodynamic coefficient in the free flight was obtained by the onboard sensors and the telemetry system. 3) The structural strength of the flare-type aeroshell sustained by the inflatable torus was measured in free flight condition to compare the flight data with the prediction of the preliminary analysis. These data will be very useful for the vehicle design in next phase of development.

21 21 Fin