James Webb Space Telescope stretches its sunshield
The James Webb Space Telescope has continued to notch up the milestones on its journey to its destination at the L2 Lagrange Point with the tensioning of its sunshield.
After a successful launch atop an Ariane 5 on 25 December, the observatory has begun unfurling as it hurtles towards its final location. After antennas and sunshield pallets popped out of the spacecraft, the sunshield itself, consisting of five folded membranes, is in the process of being tensioned.
The first layer of the observatory’s kite-shaped sunshield, and the one that is both the largest and closest to the Sun, was tightened to its final, completely taut position on 3 January. The second layer took 74 minutes and the third 71 minutes. By the completion of the third layer, NASA reported that the process (up to that point) had taken five and a half hours.
The fourth layer was successfully tensioned earlier today. The fifth is expected to be completed by the end of the day should things continue to go to plan.
The sunshield is 21.197m x 14.162m (69.5ft x 46.5ft).
“The membrane tensioning phase of sunshield deployment is especially challenging because there are complex interactions between the structures, the tensioning mechanisms, the cables and the membranes,” said James Cooper, NASA’s Webb sunshield manager, based at Goddard Space Flight Center.
“This was the hardest part to test on the ground, so it feels awesome to have everything go so well today.”
The sunshield is vital because the telescope must be protected from the Sun’s radiation. Tensioning and keeping the layers apart is also essential since if they touch, they conduct heat. “Thus the cold side can’t, well, get very cold,” remarked Mark McCaughrean, senior advisor for Science & Exploration at ESA.
Unlike other infrared observatories, which have required active cooling via cryogenics, the James Webb Space Telescope uses passive cooling to get temperatures down to -233°C for three of its instruments – the Near Infrared Camera (NIRCam), the Near Infrared Spectrograph (NIRSpec), and the Near Infrared Imager and Slitless Spectrograph (NIRISS). NIRISS includes the Fine Guidance Sensor (FGS) used to point the observatory precisely.
A fourth instrument, the Mid-Infrared Instrument (MIRI), uses a dedicated cryo-cooler to bring the temperature down even further, to 7 Kelvin (or just under -266.1°C).
The tensioning of the sunshield, while a critical step, does not mean that scientists and engineers on Earth will able to retreat from the edge of their seats. There remains the deployment of the secondary mirror and the unfolding of the iconic primary mirror among other steps ahead of the L2 insertion burn some 29 days after launch.
And then there is the commissioning of the payload.
“There’s another five & a half months of this to go,” McCaughrean tweeted.
Five and a half months that, just a few short years ago, seemed impossibly distant.
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bobarance
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More science fiction garbage. The Earth is Flat and covered by a Firmament. Space is Science Fiction. Hey that might be a good name for this controlled opposition website: “Principia Science Fictionia”!
Please stop lying to the few open minds in this upside down world with your science fiction space jam fantasies.
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WhoKoo
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Hi Bobarance.
I would like to follow you to the edge of the Earth, and then off it.
When I grow up I would like to be a troll. I still have some catching up to do.
So much to learn, so little time.
Have a nice sun off and sun on. ( day ) Whokoo
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bobarance
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You would like to follow me to the edge eh? Kind of tough to do there Whokoo. First you would need the funds to get a sea going vessel worthy of the trip. Then you would need a permit from a Country that could issue one to travel past 60 South Latitude. Then you would arrive at an ice wall along the shores of Antarctica anywhere from 150 to 200 feet high. Somehow you would need ice climbing equipment and or a helicopter to gain access to this ice plateau. Then you would face temperatures so cold that your survival would be at risk. As you continued South (if you made it this far) there would be nothing but Ice and rock. No water, no food……nothing. I don’t know exactly what you would find and how far you would have to go before you found anything. But you would not need to to worry about an edge to the best of my knowledge.
I am not here to troll. Just to open minds and discuss how silly the lies of space are.
Like I said this site clearly calls out the lies of Global warming and the Plandemic. Lies so huge and evil that it blows the mind. And yet……the vast oceans of sheep still think they live on a spinning ball. I guess they would force a kill shot on you and lie all about it but never lie about space……is that it???
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Whokoo
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Thank you Bob.
This is a bit beyond me so I may leave it for Jerry the chemistry scientist to sort out. He understands multiple hypotheses while I run out of fingers and toes for multiple hypothesis.
Plus James is a genius so he may be able to progress some concepts.
Do not trust Herb. He thinks ultraviolet light comes from the sun. He grows good veges but it may be his eyes are too close together.
Good Luck. Whokoo.
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Herb Rose
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Hi Bobarance,
The ancient Greeks knew the Earth was a sphere because when they travelled to Egypt they observed different constellations in the sky. It was only later when the bible spoke of the four corners of the Earth that flat Earth became the established theory.
You can make the observation yourself, if you are willing to look at evidence. Go to a port where one of those giant cruise ships goes. (you can write off a vacation as research.) With a pair of binoculars watch the ship go out to sea. You will see as the ship gets further away it sinks into the ocean rather than disappear by growing smaller. Yet even though you see the ship sinking none of the people on it drowned and the ship will return to port intact. Do you believe what you see or what what you accept as true? What is the basis of your flat Earth belief? Is it experience or just what someone has told you?
Herb
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bobarance
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Hi Herb. Thanks for asking. I heard about the Earth potentially not being a globe back in July of 2015. I ignored this nonsense for quite some time. But I finally started looking into it. Back then youtube was wide open with no censorship like there is now. I watched a bunch of videos from a guy named Eric Dubay and became interested. But it was too much of a challenge to my world view. So I decided to debunk this theory. I spent several months watching every video I could find on the subject, reading books, making observations, conducting tests, etc. After several months I was much more convinced that the earth was flat than it was a spinning globe. A few examples: If the earth was a globe, according to NASA it spins once per day and based on the size of the globe if you stood on land near the equator your tip speed would be in excess of 1,000 MPH. Yet one theoretically could wake up in the morning in Quito Ecuador, board a plane to Iceland and then continue to say on a ship at the North Pole and you would be experiencing a zero tip speed. How is that possible? We have all experienced the massive difference on a Merry go round between being at the center of rotation versus hanging on for dear life just a few feet to the edge. Why would it be any different on a globe? Yet no such difference exists.
Here is another one: How come if the Universe is a constantly expanding product of the big bang, can we still see the exact same constellations that were charted and recorded thousands of years ago? I can go outside and see Orions belt in December or June, yet based on the model presented by NASA, I should be looking in one direction into the night sky and 6 months later, be looking 180 degrees in the other direction. Yet I still see Orion’s belt? Not possible, but there it is. As for your ship example, I have done it. I watch the ship “dissapear” or “go away” but yet if I then use a telescope or set of binoculars, it re-appears. Because it just exceeded my visual range before. Eventually it will dissapear due to the laws of perspective, atmospheric humidity, pollution, dust, etc. I could go on and on.
Andy
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What utter garbage.
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MattH
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Hi Andy.
Very perceptive of you. Whilst it has been a source of amusement that amusement has about run it’s course.
Have a great year.
Matt
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