惑星分光観測衛星プロジェクトチーム

Hitoshi Kuninaka

  (國中 均)

Profile Information

Affiliation
Director General, Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency
Degree
Ph.D(Mar, 1988, The University of Tokyo)
Master(Mar, 1985, The University of Tokyo)

ORCID ID
 https://orcid.org/0000-0002-6871-3133
J-GLOBAL ID
200901080116851867
researchmap Member ID
1000144511

External link

Dr. Hitoshi Kuninaka received his Ph.D from the University of Tokyo in 1988. He was promoted to Associate Professor and Professor of the Japan Aerospace Exploration Agency, Japan, in 2000 and 2005, respectively. He held concurrently the post of Professor in the Department of Aeronautics and Astronautics, University of Tokyo, Japan, from 2004 to 2018. In 2018, he became the Director General of the Institute of Space and Astronautical Science (ISAS) as well as Vice President of Japan Aerospace Exploration Agency (JAXA).
 
He researches the plasma interaction of satellites and develops electric propulsions. He participated in the satellite project, Space Flyer Unit, from 1988 to 1996, and successfully brought it back to Earth via Space Shuttle STS-72. Microwave discharge ion engines, which were invented and developed by Dr. Kuninaka, took Hayabusa explorer on a round-trip journey between Earth and an asteroid from 2003 to 2010. The engines also have been propelling Hayabusa2 explorer toward another asteroid since 2014. The Hayabusa project team has been honored with the National Science Society (NSS) Space Pioneer Award, American Institute of Aeronautics and Astronautics (AIAA) Electric Propulsion Outstanding Technical Achievement Award, NSS Von Braun Award, International Academy of Astronautics Laurels for Team Achievement, SpaceOps Organization International SpaceOps Award for Outstanding Achievement among others. He received AIAA Fellow membership in 2012 and IAA Space Engineering Section Correspond Member in 2019.


Major Awards

 39

Major Papers

 163
  • Hitoshi KUNINAKA
    Vacuum and Surface Science, 63(4) 183-188, Apr 10, 2020  InvitedLead author
    The microwave discharge plasma sources contributed to the reciprocating powered flight between Earth and the asteroids as the main propulsion system of the Hayabusa and Hayabusa2 asteroid explorers, and showed its high performance. The electron cyclotron resonance discharge only heats the electrons and does not induce ion sputtering damage. The reasons of high performance and long life are derived and proved theoretically, experimentally, and in practical use in space. In addition to further space applications, efforts are also being made for industrial applications.
  • J. Inst. Electrostat. Jpn., 44(3) 128-134, Mar, 2020  Peer-reviewedLast author
    Electric charge accumulation can cause failure during vacuum manufacturing processes. For the charge neutralization in vacuum environment, cyclical change of its pressure to produce intermittent passive discharges according to the Paschen's law is often used; however, it is still insufficient to increse production efficiency. The goal of this study is to increase the charge neutralization rate in vacuum environments (10-10-4 Pa) using an electron cyclotron resonance (ECR) plasma source developed by JAXA (Japan Aerospace Exploration Agency) to neutralize the charge of spacecrafts emitting ions from their thrusters. We investigated the charge neutralization of a 50 mm × 50 mm plate with capacitance of 1.7 μF at initial voltage of 200 V, where the plate is placed 30 cm away from the ECR neutralizer. The time required to reach 37% of the initial voltage was 0.1 s for positive charge and 27 s for negative charge. In addition, improvement of the electron extraction electrode for the ECR neutralizer led to five times higher neutralization current compared to the previous ECR neutralizer at 10 W power and 0.1 mg/s xenon flow rate.
  • Kazutaka Nishiyama, Satoshi Hosoda, Ryudo Tsukizaki and Hitoshi Kuninaka
    Acta Astronautica, 166 69-77, Jan, 2020  Peer-reviewedLast author
  • 85(7) 553-559, 2016  Invited
  • 國中
    日本惑星科学会誌, 22(2), 2013  Invited
    宇宙工学は、宇宙への往来の実現を目指し、技術を切磋琢磨してきた。その成果の端的な例は、「はやぶさ」にて実現された地球〜小惑星間往復航行(2003年〜2010年)である。それにより、科学や技術分野を越えて、より大きな世界観を得ることができた。次の新しい知見を得るために、科学的な意義はもちろんのこと、「宇宙を自在に往来する独自能力の維持発展」と「人類の活動領域の宇宙への拡大」という宇宙工学・宇宙探査に跨る目標を担い、「はやぶさ2」小惑星探査ミッションが開発中である。
  • 川口, 國中
    日本航空宇宙学会誌, 59(694), 2011  Invited
  • Hitoshi Kuninaka, Kazutaka Nishiyama, Ikko Funaki, Tetsuya Yamada, Yukio Shimizu, Jun'ichiro Kawaguchi
    JOURNAL OF PROPULSION AND POWER, 23(3) 544-551, May, 2007  Peer-reviewed
  • 國中
    プラズマ・核融合学会誌, 82(5) 300-305, May, 2006  InvitedLead author
    プラズマ生成に直流放電を利用する従来式電気ロケットは、放電電極損耗という劣化要素を含み、長寿命・高信頼を必須とする宇宙機械において重大な問題を抱えていた。これをマイクロ波放電による無電極化にて根本的に解決し、日本独自のシステムとしてマイクロ波放電式イオンエンジンが開発された。「はやぶさ」小惑星探査機は、2003年5月から2年余を掛けて、太陽距離0.86天文単位から1.7天文単位に至る広範な宇宙を走破して、目的天体「いとかわ」とのランデブーに成功した。この間、主推進装置である4台のマイクロ波放電式イオンエンジンは、22kgの推進剤キセノンを消費して、総増速量1,400m/s、延べ作動時間25,800時間という世界一級の成果を挙げた。慣性(弾道)飛行していたこれまでの「人工惑星」「人工衛星」とは異なり、高性能推進機関を搭載する宇宙機は、動力航行する能力を持ち、「宇宙船」に分類されるべき新しい技術である。
  • 国中均, 堀内泰男, 西山和孝, 船木一幸, 清水幸夫, 山田哲哉
    日本航空宇宙学会誌, 53(618) 203-210, Jul, 2005  Invited
  • H Kuninaka, P Molina-Morales
    ACTA ASTRONAUTICA, 55(1) 27-38, Jul, 2004  Peer-reviewedLead author
  • 国中均, 西山和孝, 清水幸夫, 都木恭一郎, 川口淳一郎, 上杉邦憲
    日本航空宇宙学会論文集, 52(602) 129-134, 2004  Peer-reviewed
    The microwave discharge ion engine generates plasmas of the main ion source as well as the neutralizer using 4GHz microwave without discharge electrodes and hollow cathodes, so that long life and durability against oxygen and air are expected. MUSES-C “HAYABUSA” spacecraft installing four microwave discharge ion engines was launched into deep space by M-V rocket on May 9, 2003. After vacuum exposure and several runs of baking for reduction of residual gas the ion engine system established the continuous acceleration of the spacecraft toward an asteroid. The Doppler shift measurement of the communication microwave revealed the performance of ion engines, which is 8mN thrust force for a single unit with 3,200sec specific impulse at 23mN/kW thrust power ratio. At the beginning of December 2003 the accumulated operational time exceeded 7,000 hours and units.
  • H Kuninaka, S Satori
    JOURNAL OF PROPULSION AND POWER, 14(6) 1022-1026, Nov, 1998  Peer-reviewed
  • KUNINAKA Hitoshi
    Aeronautical and space sciences Japan, 46(530) 174-180, Mar, 1998  Invited

Misc.

 66

Major Books and Other Publications

 5

Presentations

 190

Major Teaching Experience

 5
  • Apr, 2005 - Mar, 2018
    電気推進工学  (東京大学大学院宇宙航空学専攻)

Major Research Projects

 17

Major Media Coverage

 9