JWST: Now

Blog Reports around the December 25 Webb Launch. Distributed as Updates to the Astronomy Community


Fully-deployed Telescope

After Launch; Day L+14. Saturday, January 8, 2022. Fully-deployed and latched Primary Mirror wings.

Webb now is a full telescope, with its Primary Mirror complete. All major mechanical deployments done. Mirror segment moves from launch stops next.

Science and space engineering are getting a great deal of positive visibility through Webb’s deployment successes. The media attention has been spectacular. It is great to have Webb now looking like our simulated images, even if unseen. And this all happened in just 2 weeks from its folded compact configuration at launch. It is remarkable that all the major deployments were done so quickly — with no serious issues or challenges. Given the complexity of JWST, this is a stunning accomplishment. All that careful testing, re-testing and cross-checking by the Webb NASA and Northrop Teams really paid off.

A bit of added info beyond what you may have seen. The NASA Live from this morning’s final primary wing deployment is here: https://www.youtube.com/watch?v=tlGTem8vkB0 The mirror wing move runs for ~4 min from ~53:20 min to when the wing reaches its hard stop. Then several hours later the latching is completed around 3h 45 min. The image below is from the NASALive video feed. It shows the real-time updated Webb simulation displayed in the MOC, and also the Webb MOC team members cheering and clapping when the second wing moved into position to make Webb’s primary mirror whole.

The press briefing that came after the completion of latching is here: https://www.youtube.com/watch?v=hET2MS1tIjA

The last 4 of the 178 non-explosive actuators (NEAs) were fired today. Having all 178 fire without any issues is a tremendous relief. At this point only 49 single point failure (SPF) items remain out of the 344 — about 85% are retired — but some would impact “only” one of the instruments, so not all 49 are SPFs that impact the full mission. 15 SPFs are in instruments. Many SPFs will also not be retired until the end of the full mission life... When it comes to SPFs we have now entered a more “normal” mission complement.

Two weeks from now Webb will be commanded to execute a small propellant burn to put itself into its halo orbit around L2 — its home until the propellant runs out, way into the future, which is now significantly over the 10 year lifetime goal.

The last few weeks have been an incredible, and exhausting time! But on refection, looking back on over 3 decades of effort by so many, it is remarkable what dedicated and committed people can do when taking an ambitious concept and carrying it through to completion, against hugely challenging technical, managerial and political odds.

Starting in less than 6 months from now, the science and discoveries from Webb, our Hubble on steroids, will be dramatic and paradigm shattering...

Garth


A Telescope is Born

After Launch Day L+11. January 6, 2022. Secondary Deployment.

A telescope is born. As the Project Manager said: "we actually have a telescope".

Today was a truly momentous day. A telescope was born. The JWST Project Manager Bill Ochs proclaimed, when the secondary latched into place, "we are 600,000 miles from Earth and we actually have a telescope”. Bill was in the Mission Operations Control room conveying his congratulations to the whole JWST team. That was right on. We don’t have a completely-aligned, fully-operational telescope and instruments by any means. That is ~5 months away. But for sure, light can, in principle, now go through JWST from objects in the universe and into Webb's instruments — albeit as 18 very fuzzy blobs, at best, until it is all tuned up!

With the secondary deployed, the remaining major deployments later this week are the release, rotation and latching of the two primary mirror backplane assembly wings (the PMBA-V2 and PMBA+V2). So at this point I am not counting all the chickens until they are latched.

The secondary deployment has been widely reported in the media and on social media, etc., but I wanted to convey a little more on that crucial deployment. And also mention two other key activities that get us closer to having a fully deployed telescope. See also https://blogs.nasa.gov/webb/ and the replay of the NASA TV Live of the secondary mirror deployment with the excellent discussion and footage https://www.youtube.com/watch?v=-EnlaXnFcGs

First — opening a cover for the mid-infrared instrument MIRI: Overnight a key step was performed on MIRI to power up the instrument control electronics (ICE) and to unlock and open a contamination cover (CCC). This successful demonstration of the ICE to power up was followed by a successful opening of the CCC. These steps were part of the early deployment sequence in the overall timeline I sent around last week, and are a key first activity of many for eventual MIRI functionality in 4-5 months after it has cooled to 7 degrees above absolute zero!

Second — the final step in the deployment of the aft deployable instrument radiator (ADIR): This deployment is planned for Thursday. The ADIR is a crucial structure on the cold telescope/instrument side that helps radiate heat away from Webb's instruments and mirrors. Eagle-eyed readers of the earlier timeline page I sent around will have noticed that ADIR deployment is listed as Part 1 and Part 2. Part 1 was an initial release of three of the non-explosive actuators that held the ADIR during launch. These first three actuators were released just after launch to prevent any strain from dimensional change in the ADIR as the telescope and ADIR cooled considerably after sunshield deployment. Part 2, the final step in the sequence, is planned for Thursday morning when the last actuator is fired and the panel does its full release, with springs driving the ADIR into its final deployed position.

Third — and most dramatically, the secondary deployment and latching: The last time the secondary was deployed and latched into position was 2.5 years ago at Northrop before the optical telescope and the instruments (OTIS) were attached to the sunshield and spacecraft (SCE). The images below give a good view of the secondary tripod and its key components as it is deployed, under its own motor power, while the primary mirror is lying on its side (since the tripod had to be on its side to allow proper gravity off-loading — note the cables). And show how large the structures are. This deployment was realistic in that the actual motors and command control was done as though Webb was in space, as well as the firing of the launch restraint mechanism. A complete secondary deployment could not be performed on the ground for the next ~2 years once OTIS and SCE were combined into the full observatory when the optical telescope system was upright in the clean room atop the sunshield. So there was a long time between secondary deployments!

There was discussion today on the NASA Live media about the drive motor and latching. These images from mid-2019 showed just how this crucial deployment and latching was carried out — to a precision of ~1.5 mm or so for the ~7 m long tripod. The discussion, the views of the MOC, and of the Webb status screen, in the replay of the NASA Live video of the secondary mirror deployment, are a good way to see what was going on: https://www.youtube.com/watch?v=-EnlaXnFcGs

With this step we are getting very close to having all the major deployments done. That is truly remarkable, given that we are less than two weeks from launch.

Garth


Sunshield Fully Tensioned

After Launch Day L+10. January 4, 2022. Sunshield Fully Tensioned.

Incredible accomplishment for Webb with the sunshield fully deployed.

This is an amazing moment, now that the sunshield is fully deployed and tensioned. And it was done quickly and smoothy. It was great to see the well-justified excitement in the Mission Operations Center (MOC). The MOC was on NASA Live this morning. Great comments at the end from the Project Manager thanking the team. It is here now: https://www.youtube.com/watch?v=IBPNi7uGgWM

Incredible accomplishment. All that thorough development and testing really paid off!

Getting closer to a full observatory, with a number of very important releases coming up, including the next major steps of the secondary deployment and the primary mirror wings, but this was an incredible accomplishment for Webb and the Webb Teams.

Garth

This is what JWST looks like now — minus all the support equipment underneath. This was taken in the Northrop M8 clean room when the sunshield was deployed last year (for the final time).


Sunshield Partially Tensioned

After Launch — Day L+9. Monday January 3, 2022. Sunshield Deployed. Partially Tensioned.

Good progress on JWST. Mid-booms and sunshield in position. Sunshield tensioning next.

Quick update after initial message below. Really great progress today. The three lowest (warmest) sunshield layers are all tensioned. Remaining two on Tuesday.

Happy New Year. The first year of many of great JWST science!

A status update (1), followed by some comments (2) on the major deployments to date, as well as the spectacular cleaned-up ESA video (3) showing separation and early solar array deployment from the Ariane VIKI camera.

(1). An update as a crucial (and one of our more complex) steps is now beginning — sunshield layer separation and tensioning. The Observatory is now taking shape with the sunshield out, but not separated and tensioned. Given this, it was decided after the mid-boom deployments Friday to pause operations for a couple of days and fully assess the new information from power systems and temperature sensors for the “real” observatory in space, in contrast to what was understood would be seen from testing and modeling JWST in the hugely-different ground environment.

For example, as mentioned on the deployment update media telecon today, some motor temperatures were a bit higher than was wanted for the start of tensioning, and the observatory has been reoriented to bring those temperatures down. Some power system adjustments and usage changes were performed also. Generally though it was noted that the observatory has been operating quite close to what was expected. Tweaks needed. Nothing dramatic. The plan from Saturday is now being followed — that is, once the "as-is Webb in space" was further characterized and adjustments made, the sunshield tensioning would begin. As noted in the telecon, the first steps towards the layer one (the lowest hottest layer) tensioning activities have started; see later blog updates on progress (https://blogs.nasa.gov/webb/)

(2). Meanwhile it is interesting to note just how far Webb has come. While essentially every deployment has the potential for being challenging (as in "very challenging" if the releases don’t work, etc), there are some deployment steps which I had mentally flagged (deployable tower; sunshield mid-booms; sunshield separation and tensioning). The complex DTA (Deployable Tower Assembly) deployment was definitely on my list. That deployment moved the whole telescope/instrument structure up about 4 ft (1.2 m) from the spacecraft, with, obviously, a whole lot of crucial power, communications and cryocooler connections. It took about 6 hrs on Wednesday to complete the move and it was a great success. This was an essential precursor to the sunshield deployment too, of course, since room was needed for the sunshield layers to be separated.

Reaching the final sunshield configuration involves several major steps. The first of these was the release of the sunshield covers on Thursday, followed the next day (Friday) by the sunshield Mid-Boom deployments. Together this ensemble of activities required firing a very large number (107) of membrane release mechanisms and long motor drives. All worked. With these done, the majority of the non-explosive actuators have now been successfully fired. The cover release appeared to go well, though, as reported, some switches did not indicate full roll-around. Some time was spent evaluating the indirect indications from temperature sensors and gyroscopic units. The data suggested that the covers had rolled out and so the motor-driven mid-boom deployment on the first side (+J2 left) was carried out (very slowly ,taking about 3 hrs to pull the five layers of sunshield out to about 7 m each side) late on Friday afternoon. It was then decided to do the second (-J2 right) mid-boom deployment Friday evening since the observatory was in a less-than-optimal asymmetric configuration with just one side out. That -J2 deployment was also very successful, with “nominal” motor power draw profiles (consistent with expected from ground tests, which is very impressive!).

With the the mid-boom deployments done, the sunshield now has its iconic 21m by 14 m footprint. Webb is starting to look like the real thing! And the majority of the non-explosive actuators have already been deployed. So Webb is well on the way to retiring a large fraction of its over 300 single point failures (as noted on the telecon, some 2/3 -3/4 of the SPFs should be retired by the end of sunshield tensioning).

Webb is now at step “3” and starting the work to carry through step “4”.

(3). Going back to launch day, ESA has released a spectacular cleaned-up video from the Ariane 5 VIKI camera on the upper stage. This shows our incredible separation, and the early deployment of the solar array — early because the attitude of Webb was spot-on after the precise Ariane 5 upper stage maneuvers and then the smooth decoupling with the spring separation of Webb. As a result, the small Monopropellant Reaction Engine thrusters (MRE) on Webb had minimal attitude corrections to make, and so the autonomous system governing array deployment gave the “Open” command. This was earlier than expected, but quite as designed, given the launch vehicle’s excellent performance. As I have said before, Ariane really nailed this launch and trajectory, and did an incredible job from the pad to separation! The drift-away VIKI video is fabulous.

The cleaned up video is on twitter https://twitter.com/esa/status/1476584214434914308 and also can be seen and downloaded from https://www.esa.int/ESA_Multimedia/Videos/2021/12/Webb_separation_from_Ariane_5

There is an extract from the ESA VIKI video here — with this magnificent image of JW just 15 seconds after its release from the upper stage — as well as an extract from the launch day video feed showing the simulated release of Webb, at the point where the Flight Manager got actual confirmation of the release, and called out “GO Webb” with his arm raised!


JWST Pre-launch

Hi Folks:

7.20 am EST (9.20 am Kourou; 4.20 am PST) on Dec 25 will be the start of the 32-min window for the Ariane 5 launch that will send JWST to its ultimate destination 1.5 million km away in a halo orbit around L2. The launch will be from the Europe Space Centre, French Guiana (Centre Spatial Guyanais CSG).

Two key events occurred over the last month. A little over a week ago JWST was mated successfully with the Ariane 5 rocket after being fueled with about 300 kg total (5% of the mass of JWST!) of its propellants, hydrazine fuel and the dinitrogen tetroxide oxidizer. Both fueling and mating operations required a delicate touch, with a lot of care, and considerable precision in both activities. They both went very well.

Between these operations JWST had to be moved in a large sealed container to the Bâtiment d’Assemblage Final (BAF), or Final Assembly Building, from its original Kourou "home" in the Satellite preparation building S5. For nearly 2 months JWST had been in the Satellite preparation building S5 after its arrival October 10 by ship from 3 years of a very comprehensive I&T (integration and test) effort at Northrop Grumman Space Park in Redondo Beach, California.

The post-shipping checkout in S5 and the launch payload adapter attachment (and clamp band, with its incident) was carried out in S5C, taking somewhat over a month. The clamp-band incident required additional careful testing and checkout that put the launch 4 days behind its initial Dec 18 date to Dec 22. Once that testing was successfully completed, indicating no damage from the shock event, a move, internal to S5, was made of JWST to the fueling facility in S5B. The potentially-hazardous fueling operation in S5B went smoothly and took a little under two weeks.

The move to the Final Assembly Building (BAF), where JWST and the Ariane rocket were to be joined for their flight, also went smoothly. A few images below are of these respective activities, showing the fueling operation, and then JWST being moved, hoisted over a hundred feet and being attached to the Ariane 5 upper stage. During these operations a lot of attention was paid to minimizing contamination. Special plastic shrouding was used to provide a tent-like clean environment for JWST as it was being attached to the rocket, and subsequently tested.

The challenge following attachment to Ariane that led to the recent 2-day launch slip resulted from connectivity issues in the external cable from JWST that enables communication to ground support and verification equipment. This cabling is essential for battery charging and for verification of "aliveness", both before and after "encapsulation" (the lowering of the fairing that covers JWST during launch). Resolving the communication issues resulted in the additional 2-day delay from the 22nd to the 24th. Following a successful aliveness test, the fairing was lowered, with great care since the clearances are not large(!), over JWST, "encapsulating" it from a last view by earthlings. Launch was then set for Dec 24.

At this point JWST is now part of its Ariane 5 for launch, designated as VA-256, and it is in the Arianespace flow typical of Ariane 5 launches. Recent Ariane 5 launches have gone very smoothly, typically launching at their designated lift-off time. Webb’s final launch readiness review was held on Tuesday Dec 21 and approved the roll-out to the launch pad for the Ariane 5 with JWST. Concerns about predicted high-altitude winds on the 24th then led to a delay for the roll-out. Launch is now set for the 25th, with roll-out to the pad on the 23rd.

Looking forward to a smooth, on-time departure early Saturday morning Dec 25 Christmas Day (fingers-crossed....)!

Thinking very positive thoughts....

Garth Illingworth

PS - The links below give the latest information and also how to get launch-day updates and viewing.

https://blogs.nasa.gov/webb/2021/12/18/nasas-webb-space-telescope-launch-confirmed-for-dec-24/

https://www.nasa.gov/press-release/nasa-sets-coverage-invites-public-to-view-webb-telescope-launch