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The James Webb Space Telescope Has Emerged From the Freezer (arstechnica.com)

Posted by BeauHD on from the one-step-closer-to-space dept.

The James Webb Space Telescope has emerged from a large vacuum chamber that was home to temperatures of just 20 degrees Celsius above absolute zero. Scientists have reviewed the data and given the instrument a clean bill of health. "We now have verified that NASA and its partners have an outstanding telescope and set of science instruments," said Bill Ochs, the Webb telescope project manager at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "We are marching toward launch." Ars Technica reports: The $10 billion telescope underwent tests inside Chamber A at Johnson Space Center, which was built in 1965 to conduct thermal-vacuum testing on the Apollo command and service modules. Beginning in mid-July, after the telescope was cooled down to a temperature range of 20 to 40 Kelvin, engineers tested the alignment of Webb's 18 primary mirror segments to ensure they would act as a single, 6.5-meter telescope. (They did). Later, they assessed the fine guidance system of the telescope by simulating the light of a distant star. The Webb telescope was able to detect the light, and all of the optical systems were able to process it. Then, the telescope was able to track the "star" and its movement, giving scientists confidence that the Webb instrument will work once in space. Webb still has a ways to go before it launches. Now that project scientists know that the optic portion of the instrument can withstand the vacuum of space, and the low temperatures at the Earth-Sun L2 point it will orbit in deep space, they must perform additional testing before a probable launch next year.

10 of 72 comments (clear)

  1. Re:Great science there by demon+driver · · Score: 2

    To put nitpicking to the highest degree, there is not even such a thing as a 'degree' of 'K'.

  2. L2 is dark by FeelGood314 · · Score: 3, Interesting

    L2 is in the earth's shadow. It will orbit around L2 in such a way that it is never in the earth's shadow but also so that it's sun shield will block light from the earth, the moon and the sun. It will also be about 6 times further from the earth than the moon.

    1. Re:L2 is dark by Anonymous Coward · · Score: 5, Informative

      L2 is quite dark because most sunlight is blocked. But in fact, there is still direct sunlight at the exact L2 point.

      This is because L2 is only in the Earth’s penumbra, not its umbra. Put another way, viewed from L2 the Earth only eclipses a large central region of the Sun. The outer parts of the Sun’s disc are still directly viewable, forming a hollow disc (donut) of light around the Earth.

      In order to receive no direct light from the Sun it would need to substatially closer to the Earth so that it is within the umbra (forming a cone volume shape).

      If Earth were a larger planet then the L2 point would be darker with no direct sunlight.
      Of course, indirect light via the Earth’s atmosphere or moonlight would still partially illuminate L2.

  3. I gotta say by 93+Escort+Wagon · · Score: 4, Funny

    “The James Webb Space Telescope has emerged from the freezer” is one of the worst secret recognition codes I’ve heard in a long time. People are going to notice that one!

    --
    #DeleteChrome
    1. Re:I gotta say by Nidi62 · · Score: 2

      “The James Webb Space Telescope has emerged from the freezer” is one of the worst secret recognition codes I’ve heard in a long time. People are going to notice that one!

      Still better than "James Webb Space Telescope has a long mustache" or "Images my heart with a monotonous languor".

      --
      The only thing necessary for evil to triumph is for it to be pitted against a slightly greater evil
  4. All those hopes and expectations... by Anonymous Coward · · Score: 2, Funny

    ... And then it will be blown to smithereens by a faulty launch vehicle.

  5. Re:Great science there by SharpFang · · Score: 3, Funny

    What? Never heard of angular temperature? 90 degrees Kelvin is either right or hot, while 0 degrees Kelvin is cold ahead.

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    45 5F E1 04 22 CA 29 C4 93 3F 95 05 2B 79 2A B2
  6. Reliability by sjbe · · Score: 2

    These multi-billion dollar space science projects always put me on edge, especially one like this which is so far from earth that there are no easy repair scenarios such as the one that saved Hubble.

    If we never go beyond repair range it's going to take an awfully long time to do anything useful in space. Gotta take some risks sooner or later.

    Anyway, hereâ(TM)s hoping that Elon can bring the cost of space flight down by a factor of ten or more so a repair mission to L2 wouldnâ(TM)t be prohibitively expensive.

    I think a better idea is to learn to make things that don't need repair missions. Harder task to be sure but necessary if we really want to explore our solar system in a serious way.

  7. 20 degrees Celsius above absolute zero?? So 20 K? by Eloking · · Score: 2

    The James Webb Space Telescope has emerged from a large vacuum chamber that was home to temperatures of just 20 degrees Celsius above absolute zero. Scientists have reviewed the data and given the instrument a clean bill of health.

    I guess 20 Kelvin was too "scientific" to be used instead of "20C above absolute zero".

    --
    Elok
  8. Re:Not done yet by Pascoea · · Score: 2

    They shake the shit out of it on earth:
    https://www.space.com/36317-ja...