あかつき―失敗を次の探査に生かせ

2010/12/11
--The Asahi Shimbun, Dec. 10
EDITORIAL: Failure of Akatsuki probe
あかつき―失敗を次の探査に生かせ

Venus, which is about the same size as Earth, is also called its twin. Repeatedly in the past, however, the planet named after the goddess of love and beauty had coldly rejected U.S. and Soviet space probes. This time, too, the goddess turned its back on a messenger from Japan.
　金星は地球とほとんど同じ大きさで双子の惑星ともいわれる。これまで何度も米ソの探査機を阻んできた冷たいビーナスの顔も持つ。日本からの使者を待っていたのも、そんな冷たい女神だったようだ。

The Japan Aerospace Exploration Agency's space probe Akatsuki failed to enter an orbit around Venus.
　宇宙航空研究開発機構（ＪＡＸＡ）の金星探査機「あかつき」が、金星を回る軌道に入るのに失敗した。

Akatsuki's mission was to seek the real face of Venus, which has turned into a blazing hell with the greenhouse effect caused by carbon dioxide getting out of control.
　あかつきは、二酸化炭素による温室効果が暴走して灼熱（しゃくねつ）地獄になったこの惑星の素顔を探るのが目的だった。

Earlier this year, after a journey of tribulations, the space probe Hayabusa returned to Earth with dust samples from the asteroid Itokawa. Akatsuki had also been launched amid big expectations.
小惑星探査機「はやぶさ」は、壮絶な旅の末に小惑星イトカワの砂を持ち帰った。あかつきも、大きな期待を背負っていた。

The result is really regrettable.
　何とも残念な結果である。

Original plans called for the probe to reverse its engine thrust, brake suddenly and enter Venus' sphere of gravitation, but the reverse thrust stopped midway. According to researchers, the ceramic engine nozzle developed with domestic technology may have broken. But first, it is important to thoroughly look into the cause of the failure.
　逆噴射して急ブレーキをかけ、金星の引力圏に入る計画だったが、噴射が途中で止まった。国産技術によるセラミック製のエンジン噴射口が壊れた可能性もあるというが、まずは、徹底的な原因究明が重要だ。

Akatsuki passed by Venus and entered an orbit to travel around the sun in about six months. Six years from now, it will once again come close to Venus. When it does, JAXA plans to try to put it into orbit again. Depending on the condition of the engine and other equipment, chances of success may not be great, but we urge the agency to make every effort.
　あかつきは金星を通り過ぎ、太陽の周りを約半年かけて回る軌道に乗っている。６年後に再び金星に近づく。そのときに再度、軌道投入を試みる。エンジンや機器の状態により、可能性は決して高くないかもしれないが、最大限の努力をしてほしい。

The Mars probe Nozomi, which was launched in 1998, also could not be put into an orbit around the red planet because of trouble in the fuel system and other equipment. With Akatsuki's failure, Japan's planet probes have failed two straight times.
　１９９８年に打ち上げた火星探査機「のぞみ」も、燃料系統や機器の故障が重なって、火星の軌道に入れなかった。惑星をめざした探査は、２回連続の黒星となった。

The gravity of the Itokawa asteroid where Hayabusa landed is weak, and the probe was able to approach it repeatedly. However, engine maneuvering to enter the gravitational sphere of a large planet with great gravitational force like Venus cannot be repeated. It is difficult because it is a one-shot deal.
　はやぶさが訪ねた小惑星イトカワは重力が小さく、何度も接近することができた。だが、金星のように重力が大きい惑星の引力圏に入るエンジン操作は、やり直しがきかない。一発勝負の難しさがある。

The history of Japan's planetary probes is short. It can even be described as immature. It is important to thoroughly study and learn from the failure this time and put it to use for future projects.
　日本の惑星探査は歴史が浅い。未熟な面があることは否めない。今回の失敗をとことん研究して学び、今後に生かすことが大切だ。

JAXA remade flight plans for Nozomi, which had little remaining fuel, to reach Mars four years later. The experience was useful in enabling Hayabusa to return to Earth three years behind schedule. This is a good precedent.
燃料が少なくなったのぞみを４年遅れで火星に到達させる飛行計画を作り直した経験が、はやぶさの３年遅れの帰還に役立った。良い前例である。

It is important to take a long view to support challenges in space, a realm that remains largely unknown.
　宇宙という未知の空間への挑戦は、長い目で支えていくことが大切だ。

The recent discovery of a bacterium in the United States that eats arsenic defied our common sense of biology. We don't know what kinds of living matter live where. Looking for the presence of life in space is a major purpose of planetary probes.
　最近、ヒ素を食べる細菌が米国で見つかった。生物学の常識を覆す発見だった。どこにどんな生命体がいるか、わからない。生命の存在を宇宙に探るのは惑星探査の大きな目的の一つだ。

But the undertaking is also very costly. Countries are launching space probes commensurate with their interests and technological capability. More researchers from around the world are taking part in joint projects. For example, as far as Venus is concerned, Japan and Europe are supposedly the leading players. Plans for Japan and Europe to cooperate and launch one space probe each to Mercury are also progressing.
　惑星探査は巨額の費用を要する。各国が関心や技術力に応じて探査機を飛ばし、世界の研究者が参加する形が増えている。たとえば、金星は当面、日本と欧州が主役のはずだった。水星でも、日欧が１機ずつ飛ばす本格的な協力計画が進む。

Also in order for Japan to live up to its international responsibility, it should clarify the problems to enhance trust and take off toward the next faraway journey into space.
　国際的な責任を果たすためにも、問題を洗い出して信頼性を高め、次のはるかな旅路に飛び立ってほしい。