Yesterday we commanded all 132 motors on Webb’s primary & secondary mirrors to move them for the first time in space! #UnfoldTheUniverse

In today’s blog, @SpaceTelescope’s deputy telescope scientist Marshall Perrin takes us through a deep dive:…👇
🚀 The Ride to Space

Each of Webb’s mirror segments has 3 metal pegs on its back, which fit snugly into matching sockets in the telescope structure. During launch, the mirrors were tucked safe and sound.
Tiny Dancers 🩰

Over about 10 days, each mirror segment will move out by 12.5 mm (about half an inch) to get the pegs clear from the sockets. It may not sound like much, but these initial moves are actually the largest moves Webb’s mirror motors will ever make in space!
🐢 Slow and Steady

The mirror control system is designed to operate only 1 motor at a time to keep things both simple and safe. To limit any heat put into Webb’s super cold mirrors, each motor is also only operated for a short time at once.
At full speed, it takes about a day to move all the segments by just 1 millimeter — about the same speed at which grass grows! 🌱

While this may not be the most exciting period for Webb, taking our time is how we’ll get closer each day to our goal of mirror alignment.

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More from @NASAWebb

10 Jan
❄️ Now that our deployments are complete, just like our telescope, we’re entering a period of cooldown. Our updates will be less frequent, but that doesn’t mean things have stopped happening:…

Thread ⬇️ Screen still of the James Webb Space Telescope's primary mir
First, what do we mean by “cooldown”? If you’ve been checking the temperatures of our “cold side” at, you can see we’re still a ways off from our operating temperatures of less than 50 Kelvin (about -370° F, or -223° C).

The deployment of our sunshield helped a lot with quickly lowering the temperatures on the cold side, but further cooling down will take place more slowly over time. The sunshield helps to passively cool Webb, meaning the optics get cold solely by being in the shade. 🌡
Read 8 tweets
8 Jan
We are GO for #NASAWebb’s final mirror wing deployment this morning! Here’s what you should expect:

🔲 Fire pins to release mirror wing
🔲 Unfold mirror
🔲 Latch the wing (2+ hours) ⏱
🔲 🥳🕺🏽🎉
🔲 #UnfoldTheUniverse! (5+ months) ✨
More: The James Webb Space Telesc...
✅ Click! We just fired the last 4 of #NASAWebb's 178 release mechanisms, or pins — all of which had to work perfectly for this unfolding to take place. These 4 will release the restraints that held Webb's mirror wing safely in place during launch. #UnfoldTheUniverse
🚗 Folks, start your engines!

As the #NASAWebb team gets ready to deploy the second primary mirror wing from @SpaceTelescope, they just completed a small motor checkout movement, ensuring the wing is ready to go. #UnfoldTheUniverse
Read 11 tweets
6 Jan
We've been hearing you loud and clear: Why doesn't Webb have cameras for its journey to #UnfoldTheUniverse? It sounds like a no-brainer, but there's more to it than meets the lens. Thread ⬇️ Artist impression of the fully deployed James Webb Space Tel
1. Light 💡

Our gold-coated mirrors were photogenic on Earth, but the mirror side of Webb is pitch dark in space. Meanwhile, the other, Sun-facing side of Webb is so shiny that cameras there would have glare & contrast issues.
2. Power 🔌

We would have to run cables and power out to cameras on Webb, and the power balance on the cold side of Webb is especially delicate. More cables adds more of a threat of heat and vibration transfer through the wires, which could impact image quality.
Read 7 tweets
4 Jan
Can you feel the tension? Webb is feeling a good way! We tensioned 3 of 5 sunshield layers yesterday. Today we start with Layer 4:…

Follow along LIVE for the final layer starting ~9:30 am ET (14:30 UTC): #UnfoldTheUniverse Screen still of the James W...
We just tensioned #NASAWebb’s sunshield some more, that was Layer 4. Now everybody look alive, it’s time to tension Layer 5! And better yet — keep watching along live: #UnfoldTheUniverse Photo of the Webb Telescope...
If you’re tuned in to our live broadcast, now’s the perfect time to go grab a drink of water! Coverage resumes at 11:30 am ET (16:30 UTC) for the tensioning of Webb’s fifth and final sunshield layer 🤩

More on our sunshield:… #UnfoldTheUniverse
Read 4 tweets
1 Jan
We successfully deployed #NASAWebb’s port sunshield mid-boom, which pulls out our 5 sunshield layers. While scheduled for earlier today, our team paused to confirm the sunshield cover had fully rolled up: #UnfoldTheUniverse

Thread ⬇️
When switches did not trigger to indicate the sunshield covers were rolled up, team members used temperature data & gyroscope sensors to confirm that they had. This analysis took extra time, but allowed the team to move forward. #UnfoldTheUniverse
The deployment of the 5 telescoping segments of the mid-boom began around 1:30pm ET and reached full deployment at 4:49pm.

Webb's deployment steps are all human-controlled, so the schedule can change. The team plans to deploy the starboard mid-boom tonight. #UnfoldTheUniverse
Read 4 tweets
27 Dec 21
Ooh, sick burn! 🔥

In this case, we’re not talking about insults, but a burn of fuel to adjust #NASAWebb’s trajectory on its million mile (1.5 million km) journey to #UnfoldTheUniverse. #ICYMI, Webb had its first mid-course correction burn Dec. 25:
So far, the post-launch journey has been smooth sailing. Burns are scheduled to leave as much remaining fuel as possible for #NASAWebb’s ordinary operations over its lifetime, like small adjustments to keep Webb in its desired orbit once it arrives. #UnfoldTheUniverse
One interesting aspect of the #NASAWebb launch and its burns is that we always "aim a little bit low." Webb's thrusters can only push Webb away from the Sun, not back toward the Sun (and Earth). We designed launch and these burns to always avoid drifting away.
Read 4 tweets

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