ＮＡＳＡの巨大宇宙望遠鏡、打ち上げ前最後の地上試験に成功

【ワシントンＡＦＰ＝時事】年内に打ち上げが予定されている米航空宇宙局（ＮＡＳＡ）のジェームズ・ウェッブ宇宙望遠鏡（ＪＷＳＴ）の最後の地上試験が１１日に行われた。（写真は米航空宇宙局＜ＮＡＳＡ＞のジェイムズ・ウェッブ宇宙望遠鏡の地上試験。カリフォルニア州にある米航空宇宙大手ノースロップ・グラマンの基地で）
　１００億ドル（約１兆１０００億円）を費やして製造された同宇宙望遠鏡は大きさ、性能ともに世界最高とされる。ＮＡＳＡによると、宇宙の起源を探る１６０万キロの旅を前にした最後の試験で、口径６．５メートルの巨大な主鏡が配置通りに展開された。
　製造を請け負った米航空宇宙大手ノースロップ・グラマンのスコット・ウィロビー氏は、米カリフォルニア州レドンドビーチにある同社の宇宙基地で、「高さ約１２メートルのスイス時計を作るようなものだ（中略）しかも、月の４倍も遠い零下２４０度の真空空間を旅できるように」と語った。
　ジェームズ・ウェッブ宇宙望遠鏡はフランス領ギアナに移送され、欧州宇宙産業大手アリアンスペースのロケット「アリアン５」で、１０月３１日に打ち上げられる予定。
　六角形のセグメント１８枚から成る同宇宙望遠鏡の主鏡は、赤外線を反射しやすいように金でコーティングされている。折り紙のようにたたまれ、ロケット先端のフェアリング部分に格納された状態で運ばれる。展開する際には、アクチュエータと呼ばれる作動装置１３２個でそれぞれの鏡の位置を調整する。これらの鏡が一つの巨大な反射体として機能することで、ジェームズ・ウェッブ宇宙望遠鏡はかつてないほど宇宙の奥深くをのぞくことができるという。【翻訳編集ＡＦＰＢＢＮｅｗｓ】

〔ＡＦＰ＝時事〕（2021/05/12-13:34）

The world's largest and most powerful space telescope unfolded its giant golden mirror for the last time on Earth on Tuesday, a key milestone before the $10 billion observatory is launched later this year.
The James Webb Space Telescope's 21 feet 4 inch (6.5 meter) mirror was commanded to fully expand and lock itself into place, NASA said -- a final test to ensure it will survive its million-mile (1.6 million kilometer) journey and is ready to discover the origins of the Universe.
It's like building a Swiss watch at 40-feet-tall... and getting it ready for this journey that we take into the vacuum at minus 400 degrees Fahrenheit (-240 Celsius), four times further than the Moon, said Scott Willoughby of lead contractor Northrop Grumman.
He was speaking at the company's spaceport in Redondo Beach, California, from where the telescope will be shipped to French Guiana to be launched on an Ariane 5 rocket, with NASA targeting October 31 for liftoff.
Webb's primary mirror is made of 18 hexagonal segments coated with an ultra-thin layer of gold to improve its reflection of infrared light.
It will fly to space folded like a piece of origami artwork, which allows it to fit inside a 16-foot (5-meter) rocket fairing, and will then use 132 individual actuators and motors to bend each mirror into a specific position.
Together, the mirrors will function as one massive reflector, to enable the telescope to peer deeper into the cosmos than ever before.
- Time machine -
Scientists want to use the telescope to look back in time over 13.5 billion years ago and see for the first time the first stars and galaxies that formed, a few hundred million years after the Big Bang.
To do this, they need to detect infrared. The current premier space telescope, Hubble, only has limited infrared capacity.
This is key because by the time the light from the first objects reaches our telescopes, it has been shifted towards the red end of the electromagnetic spectrum as a result of the Universe extending the space between objects as it expands.
Another key area will be the discovery of alien worlds. The first planets to orbit other stars were detected in the 1990s and there are now more than 4,000 exoplanets that have been confirmed.
Webb has instrumentation that will propel this new and exciting field into its next epic of discovery, said Eric Smith, James Webb telescope program scientist.
Scientists from 44 countries will be able to make use of the telescope, with proposals including using the infrared capabilities to penetrate the supermassive black holes at the center of galaxies, including our own.
The discovery capability of Webb is limited only by our own imaginations, and scientists around the world will soon be using this general purpose observatory to take us places we haven't dreamed of going before, said Smith.