Space

James Webb Space Telescope completes deployment as mirror opens

James Webb Space Telescope com...
Artists depiction of the JWST showing the huge 5-layered sunshield
Artists depiction of the JWST showing the huge 5-layered sunshield
View 3 Images
The 6.5 m James Webb Space Telescope could herald a new age for astronomy (Image: NASA/Northrop Grumman)
1/3
The 6.5 m James Webb Space Telescope could herald a new age for astronomy (Image: NASA/Northrop Grumman)
The shield consists of five extremely thin layers of a coated polymer called Kapton
2/3
The shield consists of five extremely thin layers of a coated polymer called Kapton
Artists depiction of the JWST showing the huge 5-layered sunshield
3/3
Artists depiction of the JWST showing the huge 5-layered sunshield
View gallery - 3 images

NASA's US$10 billion James Webb Space Telescope has completed its final deployment without a mishap. Starting today at 8:53 am EST, the starboard wing of the 21-ft (640 cm) gold-plated primary mirror began to swing, locking into position at 1:17 pm.

Today's unfolding of the last part of the giant space telescope marks the end of a nail-biting series of events for the Webb since its long-delayed launch on December 25, 2021. Because the telescope and its supporting spacecraft are so large, the whole thing had to be folded up like an elaborate and very expensive piece of origami to allow it to fit into the nose cone of the Ariane 5 rocket that hurled it into space.

While this arrangement did allow the Webb to be launched, it presented NASA and its partners at ESA and the Canadian Space Agency with a problem. Normally, once a spacecraft is in orbit, that's pretty much job done except for unfolding some solar arrays and an antenna, but with the Webb, things were much more complicated with many more chances of something going wrong.

The first deployment after launch was the simplest and even routine as the solar array to power the spacecraft unfolded, followed by the antenna array to maintain radio contact with Earth. Then the forward and aft pallets supporting the sun shield that protects the telescope against the light and heat of the Sun, Earth, and Moon unfolded. After this, the telescope extended slightly from the spacecraft bus on a boom to further insulate it and a flap opened that acts like a sail to use the solar winds to stabilize the telescope's attitude.

Then came the trickiest part. The port and starboard booms used to unfurl the sun shield were extended and then the shield itself was deployed. The shield consists of five extremely thin layers of a coated polymer called Kapton, each covering an area the size of a tennis court. With a small space between each layer to allow trapped heat to radiate away, each layer is successively cooler, allowing one side of the shield to keep a temperature of -370 °F (-223 °C) on the telescope side and 230 °F (110 °C) on the sunward side.

Because the shield is so large, yet so delicate, it had to be furled in an intricate pattern. When it came time to deploy it, first on the port side and then the starboard, 107 actuators had to work perfectly to make sure it opened properly without tearing. This was followed by carefully tensioning each layer to put them into the correct positions.

The shield consists of five extremely thin layers of a coated polymer called Kapton
The shield consists of five extremely thin layers of a coated polymer called Kapton

Once this was completed, mission control ordered the Webb to deploy the radiator used to keep the instruments supercooled, the secondary mirror that directs the light collected by the primary mirror to the instruments, and then the wings of the primary mirror. The port wing swung into place on January 7 and the starboard wing today.

Though the telescope is now fully deployed, there's still a lot of work to be done. The 18 hexagonal segments of the primary mirror are controlled by a set of 126 motors and the segments have to be fully tested and calibrated over the course of the coming months. The craft's systems must also be given a thorough going over before it's commissioned and can begin its science mission to study the early history of the universe.

Meanwhile the spacecraft will carry out a course correction burn that will send it into orbit around the Lagrange 2 (L2) point about one million miles (1.5 million km) from Earth, where the gravitational fields of the Sun and the Earth cancel one another out, allowing the telescope to maintain a stable position in space.

"Today, NASA achieved another engineering milestone decades in the making," says NASA Administrator Bill Nelson. "While the journey is not complete, I join the Webb team in breathing a little easier and imagining the future breakthroughs bound to inspire the world. The James Webb Space Telescope is an unprecedented mission that is on the precipice of seeing the light from the first galaxies and discovering the mysteries of our universe. Each feat already achieved and future accomplishment is a testament to the thousands of innovators who poured their life’s passion into this mission."

The video below shows the entire deployment sequence.

JWST Deploy

Source: NASA

View gallery - 3 images
8 comments
8 comments
FB36
"Because the telescope and its supporting spacecraft are so large, the whole thing had to be folded up like an elaborate and very expensive piece of origami to allow it to fit into the nose cone of the Ariane 5 rocket that hurled it into space.":

That is actually a really huge problem for humanity commercializing/mining space!
Nose cones of all rockets have very limited space & there is a huge need for sending much larger objects into space!
Imagine how much helpful it would be to be able to send bulldozers & tunnel boring machines to Moon, for example!
Solution?
How about designing a very large dome spacecraft that is carried into space by 3/4/5/6 rockets (holding/carrying it from its edges/circumference)!
blanky2
FB36..I am no scientist but...
My take on it is, if you look at all the profiles of projectiles man has created...Spear, arrow, bullet, shell. missile. rocket etc etc..the common denominator with them all is that to aid their accuracy and efficiency, they all have as small a frontal area as possible. Add in the force of gravity ? I suspect man will always have to erect larger objects either already in orbit (space) or at their final destinations.
Perhaps there is already a theory or formula that explains the limitations as to what can be launched (currently) into space ?
Gary Robinson
Big + Heavy = tough luck ..... squared
c2cam
How cool would it have been to be sitting out there watching it deploy.
1stClassOPP
So, how could you determine that you would be viewing the “first” galaxies, and just how would it be useful discovering the “mysteries “ of our universe? I have a hunch that all this effort is an attempt to prove, or disprove the existence of God.
blanky2
Surprised the link to JWST wasn't added..lots of excellent vids on here and to keep up with developments, which will surely last for years to come. And for C2cam (below) I think it might have been a tad cold for you to be sitting out there watching it deploy, as it was over a period of 11+ days and a bit chilly too.
https://webb.nasa.gov/content/webbLaunch/whereIsWebb.html
c2cam
@blanky2 - lol, I'm surprised I overlooked my pun.
Ornery Johnson
Genuinely exciting moment in science/space exploration and for theoretical physicists. I wonder if the Webb telescope will be able to detect the quantity of dark matter in the earliest galaxies and whether that dark matter is associated with primordial black holes created during the initial expansion of the universe.

On a separate tangent, there is no way for this telescope, or science in general, to either prove or disprove anything that is not a part of the physical universe (and therefore not subject to empirical investigation). I'm sure there are many God-fearing scientists working with this telescope as well as many atheists. They're all undoubtedly aware that nothing this telescope shows us will disprove either belief-system.