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Kazuhisa Fujita / Professor / Division of Transdisciplinary Sciences
Department of Advanced Energy / / High-Temperature Gas Dynamics, Thermal Protection System, and Its Space Applications
http://www.k.u-tokyo.ac.jp/ae/e/res/ren01_e.html
http://www.aero.jaxa.jp/research/ryutai/ryu-atmos.html

Career Summary
1989: Graduated, Faculty of Engineering, The University of Tokyo
1995: Doctor of Engineering from The University of Tokyo
1995: Research Associate, The Institute of Space and Astronautical Science
1997: Visiting Research Associate, The University of Tokyo
2003: Chief Researcher, Japan Aerospace Exploration Agency
2003: Visiting Associate Professor, The University of Tokyo
2008: Senior Researcher, Japan Aerospace Exploration Agency
2012: Visiting Professor, Shizuoka University
2013: Visiting Professor, The University of Tokyo
Educational Activities
Graduate School : Advanced Energy
Research Activities
High-temperature gas dynamics, hypersonic aerothermodynamics, radiation, and thermal protection systems related to atmospheric entry systems for exploration of massive planets with an atmosphere (especially Mars and Venus), sample return missions, and earth reentry missions, as well as applications to mission design and spacecraft development.

1) Development of thermochemical models for assessment of hypersonic flight environments
Very complicated thermal and chemical processes occur behind the strong shock waves produced ahead of the vehicle in hypersonic flight. Since these thermochemical processes determine the behavior of high-temperature gases in contact with the vehicle, it is of utmost importance to accurately model such processes for the assessment of aerodynamic performance and heat transfer rate to the body surface of the vehicle. In our laboratory at JAXA, fundamental research has been conducted in both analytical and experimental approaches, using a high-enthalpy wind tunnel, hypervelocity shock tubes, and high-speed shock tunnels (see Refs. 1-3).

2) Development of an advanced thermal protection system and its evaluation technologies
In addition to the gas-phase thermochemical processes stated above, it is important to understand gas-surface reactions in order to assess the aerodynamic heating rate of the body surface and to evaluate performance of the thermal protection system. In our laboratory at JAXA, development of the advanced thermal protection system is being undertaken in collaboration with the materials group and the JAXA Space Exploration Center (JSPEC). Advanced technologies to evaluate performance of the thermal protection system have been developed with verification using experimental facilities, such as the arc-heater and the inductively-coupled plasma wind tunnel (see Refs. 4 and 5).

3) Development of analytical tools for rarefied gases and intermolecular collisions
It is well known that rarefied gases at the high altitude and in the interplanetary space show different behaviors from those of dense gases, which can be regarded as a continuum. In order to offer accurate predictions of gas behavior, development of numerical analysis technologies for rarefied gases is undertaken in our laboratory (see Refs. 6-8). In addition, to improve gas-phase thermochemical models, numerical research is performed by molecular dynamic approaches and quantum chemical analysis (see Refs. 9 and 10).

4) Modeling and application of high-energy radiation heat transfer
As the flight velocity exceeds 10 km/s, which is the case for atmospheric reenty from interplanetary orbits, the influence of radiation heat transfer on the thermochemical behavior of gases becomes significant. In our laboratory, high-accuracy modeling of radiation processes is undertaken, with respect to the vacuum ultraviolet and ultraviolet wavelength ranges where radiation energy transfer is significant (Ref. 2). The radiation code is applied not only to the assessment of the radiative heat transfer rate for planetary entry vehicles in the mission design phase, but also to spectroscopic measurements of high-temperature gases to deduce the molecular temperatures and component concentrations (see Refs. 11-14).

5) Applications to mission design
The technologies and tools described above are being applied to conceptual studies and mission designs of planetary atmospheric entry systems for future JAXA projects (see Refs. 15-18). Our group is currently a chief member for entertaining Japan's first Mars rover mission, namely MELOS (= Mars Exploration for Live Organism Search) shown in Fig.1, and world's first Mars sample return mission, namely MASC (=Mars Aeroflyby Sample Collection), shown in Fig. 2.


Fig.1. Conceptual view of MELOS (=Mars Exploration for Live Organism Search) mission
Fig.1. Conceptual view of MELOS (=Mars Exploration for Live Organism Search) mission



Fig.2. Conceptual view of MASC (=Mars Aeroflyby Sample Collection) spacecraft
Fig.2. Conceptual view of MASC (=Mars Aeroflyby Sample Collection) spacecraft

Literature
1) Fujita, K., Otsu, H., Yamada, T., and Abe, T., "Assessment of Radiative Reentry Environment around MUSES-C Capsule," Journal of Japan Society for Aeronautical and Space Sciences, Vol.51, No.595, pp.419-426, (2003).

2) Fujita, K., Sumi, T, Yamada, T., and Ishii, N., "Heating Environments of a Venus Entry Capsule in a Trail Balloon Mission," Journal of Thermophysics and Heat Transfer, Vol.20, No.3, pp.507-516, (2006).

3) Yamada, G., Suzuki, T., Takayanagi, H., and Fujita, K., gDevelopment of a Shock Tube for Improvement of Reentry Flight Technology,h Transactions of the Japan Society for Aeronautical and Space Sciences, Vol.54, No.183, pp.51-61, (2011).

4) Suzuki, T., Fujita, K., Sakai, T., h Experimental Study of Graphite Ablation in Nitrogen Flow,h Journal of Thermophysics and Heat Transfer, Vol.22, No.3, pp.382-389, (2008).

5) Suzuki, T., Fujita, K., Sakai, T., Okuyama, K., Kato, S., and Nishio, S., gThermal Response Analysis of Low-Density CFRP Ablator,h Transactions of the Japan Society for Aeronautical and Space Sciences, Aerospace Technology Japan, Vol.10, No.ISTS28, pp. Pe_21-Pe_30, (2012).

6) Fujita, K., "Air Intake Performance of Air Breathing Ion Engines," Journal of Japan Society for Aeronautical and Space Sciences, Vol.52, No.610, pp.514-521, (2004).

7) Fujita, K., Inatani, Y., and Hiraki, K., "Attitude Stability of Blunt-Body Capsules in Hypersonic Rarefied Regime," Journal of Spacecraft and Rockets, Vol. 41, No.6, pp.925-931, (2004).

8) Fujita, K., "Particle Simulation of Moderately-Sized Magnetic Sails," Journal of Space Technology and Science, Vol.20, No.2, pp.26-31, (2005).

9) Fujita, K., "Assessment of Molecular Internal Relaxation and Dissociation by DSMC-QCT Analysis," AIAA Paper 2007-4345, 39th AIAA Thermophysics Conference, (2003).

10) Fujita, K., "DSMC-QCT Analysis of CO Internal Relaxation and Dissociation by CO-O Collisions, " Journal of ‚”he Japan Society for Aeronautical and Space Sciences, Vol.57, No.669, pp. 405-414, (2009).

11) Fujita, K., Sato, S., Abe, T., and Ebinuma, Y., "Experimental Investigation of Air Radiation from behind a Strong Shock Wave," Journal of Thermophysics and Heat Transfer, Vol.16, No.1, pp.77-82, (2002).

12) Fujita, K., Sato, S., Abe, T., and Otsu, H., "Electron Density Measurements behind Strong Shock Waves by H Beta Profile Matching," Journal of Thermophysics and Heat Transfer, Vol.17, No.2, pp.210-216, (2003).

13) Fujita, K., Mizuno, M., Ishida, K., and Ito, T., gSpectroscopic Flow Evaluation in Inductively Coupled Plasma Wind Tunnel,h Journal of Thermophysics and Heat Transfer, Vol.22, No.4, pp.685-694, (2008).

14) Fujita, K., Suzuki, T., Mizuno, M., Fujii, K, gComprehensive Flow Characterization in a 110-kW Inductively-Coupled-Plasma Heater,h Journal of Thermophysics and Heat Transfer, Vol.23, No.4, pp. 840-843, (2009).

15) Fujita, K., Kubota, T., Ogawa, J., Morimoto, M., Suzuki, T., Takayanagi, H., Yamada, T., Kawaguchi, J., gAssessment of Aeroassist Orbital Maneuver Technologies for Next Mars Exploration,h Transactions of the Japan Society for Aeronautical and Space Sciences, Aerospace Technology Japan, Vol.8, No.ists (ISTS Special Issue: Selected papers from the 27th International Symposium on Space Technology and Science), pp. Pk_23-Pk_29, (2010).

16) Fujita, K., Tachibana, S., Sugita, S., Miyamoto, H., Mikouchi, T., Suzuki, T., Takayanagi, H., Kawaguchi, J., gFeasibility Assessment of Nonstop Mars Sample Return System Using Aerocapture Technologies,h Transactions of the Japan Society for Aeronautical and Space Sciences, Aerospace Technology Japan, Vol.8, No.ists (ISTS Special Issue: Selected papers from the 27th International Symposium on Space Technology and Science), pp. Pk_31-Pk_38, (2010).

17) Fujita, K., Yamamoto, M., Abe, S., Ishihara, Y., Iiyama, O., Kakinami, Y., Hiramatsu, Y., Furumoto, M., Takayanagi, H., Suzuki, T., Yanagisawa, T., Kurosaki, H., Shoemaker, M., Ueda, M., Shiba, Y., and Suzuki, M., gAn Overview of JAXA's Ground Observation Activities for Hayabusa Reentry,h Publications of the Astronomical Society of Japan, Vol.63, No.5, pp.961-969, Oct. (2011).

18) Fujita, K., Ozawa, T., Okudaira, K., Mikouchi, T., Suzuki, T., Takayanagi, H., Tsuda, Y., Ogawa, N., Tachibana, S., and Satoh, T., gConceptual Study and Key Technology Development for Mars Aeroflyby Sample Collection,h Acta Astronautica, Vol.93, pp.84-93, Jan. (2014).
Other Activities
The Japan Society for Aeronautical and Space Sciences (JSASS)
American Institute of Aeronautics and Astronautics (AIAA)
The Japan Society of Mechanical Engineering (JSME)
Japan Society of Fluid Dynamics (JSFD)
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Future Plan
One of the goals of our laboratory is to send a MELOS spacecraft to Mars by 2020, and to design the succedent Mars missions.
Messages to Students
The areas of research in our laboratory range from fundamental researches to mission-oriented projects. Every young researcher interested in our research is welcome to join. The only requirements are a passion for research and a dream for space!
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