美国国家航空航天局NASA每日一图-2017年6月19日

Webb Telescope Set for Testing in Space Simulation Chamber

NASA’s James Webb Space Telescope sits in front of the door to Chamber A, a giant thermal vacuum chamber located at NASA’s Johnson Space Center.  The telescope will soon be moved into the chamber, where it will spend a hot Houston summer undergoing tests at sub-freezing cryogenic temperatures.  The telescope will operate below an extremely cold 50 K (-223° C or -370° F) in space, so NASA is simulating those conditions on the ground, ensuring the optics and instruments will perform perfectly after launch.

In space, the telescope itself must be kept extremely cold, in order to be able to detect the infrared light from faint and very distant objects. To protect the telescope from external sources of light and heat (like the sun, Earth, and moon) as well as from heat emitted by the observatory itself, a five-layer, tennis court-sized sunshield acts like a parasol providing shade. The sunshield separates the observatory into a warm, sun-facing side (reaching temperatures close to 400 degrees Farenheit), and a cold side (185 degrees below zero) where the sunlight is blocked from interfering with the sensitive telescope instruments.

The James Webb Space Telescope is the scientific successor to NASA's Hubble Space Telescope. It will be the most powerful space telescope ever built. Webb is an international project led by NASA with its partners, ESA (European Space Agency) and the Canadian Space Agency.

For more information about the Webb telescope visit: www.jwst.nasa.gov or www.nasa.gov/webb

Image Credit: NASA/Desiree Stover

Last Updated: June 21, 2017
Editor: Sarah Loff

Webb望远镜设在空间模拟室中进行测试

NASA的詹姆斯·韦伯空间望远镜坐落在美国宇航局约翰逊航天中心的一个巨大的热真空室A舱门前。望远镜将很快移入室内,在那里将在休斯敦炎热的夏天进行低温低温测试。望远镜将在空间极低的50 K(-223°C或-370°F)下运行,因此美国宇航局正在模拟地面上的这些条件,确保光学和仪器在发射后能够完美地运行。

在太空中,望远镜本身必须保持极冷,以便能够检测到微弱和非常远的物体的红外光。为了保护望远镜免受外部光源和热源(如太阳,地球和月亮)以及天文台本身散发的热量,五层网球场大小的遮阳板的作用就像遮阳伞一样。遮阳板将天文台分成一个温暖的阳光正面(达到接近400度Farenheit的温度),以及一个寒冷的一面(在零度以下185度),防止阳光干扰敏感的望远镜仪器。

詹姆斯·韦伯空间望远镜是NASA哈勃太空望远镜的科学继承人。它将是迄今为止最强大的太空望远镜。 Webb是NASA与其合作伙伴ESA(欧洲航天局)和加拿大航天局牵头的国际项目。

有关Webb望远镜的更多信息,请访问:www.jwst.nasa.gov或www.nasa.gov/webb

图片来源:NASA / Desiree Stover

最后更新:2017年6月21日
编辑:莎拉·洛夫

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