To the Moon and Beyond

オリオン宇宙船 月へ,その先へ

By Charles Dingell /William A. Johns/Julie Kramer White C. ディンゲル /W. A. ジョーンズ/J. クレーマー=ホワイト
English 日本語 日本語
The moon, a luminous disk in the inky sky, appears suddenly above the broad crescent of Earth's horizon. The four astronauts in the Orion crew exploration vehicle have witnessed several such spectacular moonrises since their spacecraft reached orbit some 300 kilometers above the vast expanse of our home planet. But now, with a well-timed rocket boost, the pilot is ready to accelerate their vessel toward the distant target ahead. "Translunar injection burn in 10 seconds ... " comes the call over the headset. "Five, four, three, two, one, mark ... ignition...." White-hot flames erupt from a rocket nozzle far astern, and the entire ship―a stack of functional modules―vibrates as the crew starts the voyage to our nearest celestial neighbor, a still mysterious place that humans have not visited in nearly half a century. The year is 2020, and Americans are returning to the moon. This time, however, the goal is not just to come and go but to establish an outpost for a new generation of space explorers. 墨を塗ったような暗黒の宇宙に,三日月形の地球が浮かんでいる。その縁から突然,燦然と輝く満月が姿を現した。地球の300km上空を周回するオリオン宇宙船に搭乗している4人の宇宙飛行士は,この3日間で同じような美しい「月の出」を何度か目にしてきた。しかし今回は,はるか前方に見えるこの目的地へ向かうため,ロケットに点火するタイミングだ。
The Orion vehicle is a key component of the Constellation program, NASA's ambitious, multibillion-dollar effort to build a space transportation system that can not only bring humans to the moon and back but also resupply the International Space Station (ISS) and eventually place people on the planet Mars. Since the program was established in mid-2006, engineers and researchers at NASA, as well as at Lockheed Martin, Orion's prime contractor, have been working to develop the rocket launchers, crew and service modules, upper stages and landing systems necessary for the U.S. to mount a robust and affordable human spaceflight effort after its current launch workhorse, the space shuttle, retires in 2010. オリオンは「コンステレーション計画」の要となる宇宙船だ(コンステレーションは「星座」の意)。米航空宇宙局(NASA)が数十億ドルを投じて進めるこの意欲的な計画は,月と地球の往復だけでなく,国際宇宙ステーション(ISS)への物資供給や,最終的には火星に人間を送り込めるような宇宙輸送システムを目指している。
To minimize development risks and costs, NASA planners based the Constellation program on many of the tried-and-true technical principles and know-how established during the Apollo program, an engineering feat that put men safely on the moon in the late 1960s and early 1970s. At the same time, NASA engineers are redesigning many systems and components using updated technology. 開発リスクとコストを最小限に抑えるため,NASAは実証ずみの基本技術とノウハウに基づいてコンステレーション計画を立案した。1960年代末から70年代初頭に人類を安全に月へ送り込むという技術的偉業を成し遂げた「アポロ計画」によって確立された技術とノウハウだ。同時に,最新技術を使って多くのシステムと部品を再設計しつつある。
Orion starts with much the same general functionality as the Apollo spacecraft, and its crew capsule has a similar shape, but the resemblance is only skin-deep. Orion will, for example, accommodate larger crews than Apollo did. Four people will ride in a pressurized cabin with a volume of approximately 20 cubic meters for lunar missions (six will ride for visits to the space station starting around 2015), compared with Apollo's three astronauts (plus equipment) in a cramped volume of about 10 cubic meters. オリオン宇宙船の多くの一般機能はアポロと共通だし,司令船の形も似ているが,同じに見えるのは表層部分だけだ。例えばオリオンはアポロよりも乗務スペースが広くなる。アポロでは約10m3の空間に3人の宇宙飛行士と機器類を詰め込んでいたが,オリオンの月ミッションでは約20m3の気密室に4人が乗る予定になっている(2015年ごろに始まる宇宙ステーションへの往復では6人が搭乗予定)。
The latest structural designs, electronics, and computing and communications technologies will help project designers expand the new spacecraft's operational flexibility beyond that of Apollo. Orion, for instance, will be able to dock with other craft automatically and to loiter in lunar orbit for six months with no one onboard. Engineers are widening safety margins as well. In the event of an emergency during launch, for example, a powerful escape rocket will quickly remove the crew from danger, a benefit space shuttle astronauts do not enjoy. But to give you a better feel for what the program involves, let us start on the ground, before the Orion crew leaves Earth. From there, we will trace the progress of a prototypical lunar mission and the technologies planned to accomplish each stage. 最新の構造設計と電子工学,コンピューター・通信技術のおかげで,運用上の柔軟性もアポロより高くなる。例えばオリオンは他の宇宙船と自動でドッキング可能になるほか,無人で月周回軌道を6カ月間も回り続けることができる。安全性も余裕をもって設計される。打ち上げ中に緊急事態が発生した場合は,強力な脱出用ロケットが乗組員を素早く危険から救い出す。スペースシャトルにはなかった利点だ。