The James Webb Space Telescope's launch date has been pushed back to no earlier than December
22nd, following an anomaly that occurred during launch prep in French Guiana. The incident
occurred on November 9th at the French Guiana Launch Center, when Arianespace technicians
were getting ready to attach Webb to the launch vehicle adapter.
So far, things had been proceeding, according to plan. Webb was delivered on October 12th
following a two-week voyage at sea. It was unboxed and inspected, and then a battery
of functional tests were performed to ensure it made the journey safely.
The next steps were to mount Webb onto its payload adapter, which is a cone-shaped structure
that's eventually bolted to the Ariane 5 upper stage. The observatory is secured to the payload
adapter with a spring loaded clamp band.
Now, it's weird to think that an eleven meter-tall spacecraft is being held in place with a small
metal band a few inches tall. But yeah, that's how it works. Anyway, the band springs open
about a half hour after liftoff.
It does this with actuators that are designed to release very rapidly, but also very smoothly
so as not to rattle the spacecraft. While this band was being tightened, it suddenly
sprang open, and evidently it did so in a way that it wasn't supposed to.
And this sent vibrations into the base of the spacecraft. Now, the good news is that
nobody was hurt because the clamp has safety features built in that prevent it from becoming
a projectile. And even better, there was apparently no visible damage to the observatory, either.
However, the incident did send vibrations into the observatory. Now, Webb has been rattled
before. While it was that NASA's Goddard Space Flight Center, the assembled telescope was
tested on a shake table that mimicked those of the launch vehicle.
While it was at Northrop Grumman, it was subjected to further acoustical testing to make sure
it could withstand the sound vibrations of launch. There was even an earthquake in California
right before it was transported. And while Webb was on board the ship, it was encountering
some moderate waves.
But when those events occurred, Webb was hooked up to vibration [sensors] that engineers could
monitor to make sure that none of the flight hardware was rattling outside of their design
limits. But all of those sensors had been removed as part of launch prep.
So when this anomaly occurred, there was no way to know just how hard things were shaken.
As soon as the anomaly happened, NASA's stopped all launch prep operations and convened an
Anomaly review board to investigate. Engineers try to estimate the amount of energy that
could have been transferred into the Observatory when the clamp band released.
Most of that energy would have gone into the spacecraft bus, which is located at the bottom
of the observatory. The bus houses the main subsystems that support the observatory. Things
like electrical power, attitude control, communications, command and data handling, propulsion, and
thermal control subsystems are all located there.
It seems like it should be easy enough to check, but Webb is folded up and closed out
for launch. To check everything, they'd have to open web back up and install the necessary
testing equipment. Not only is that labor intensive, but anytime you test hardware,
there's always a risk of causing further damage.
So the testing has been underway for some time now, but it's proceeding slowly and carefully.
Until this point, NASA was on track for a December 18 launch. They had two weeks of
schedule reserves remaining, but they used up that time, plus a few extra days while
they tested everything.
On November 20th, the Anomaly board decided that out of an abundance of caution, there
should be additional testing done on some of the subsystems. So that's why NASA announced
that Webb's launch will now be delayed to no earlier than December 22nd.
They're going to need a few more days to complete the extra testing, and they'll hopefully make
another announcement soon. Now, obviously, none of this is good news, but it does make
sense to take an extra few days to make sure everything still works.
After all, there's no way NASA's going to let a 10 billion dollar telescope launch without
knowing whether it's good to go. So hopefully everything goes well with these remaining
tests, and the review board releases Webb to proceed with flight prep, and that'll include
getting its fuel loaded on board, which will be used to maintain its orbit throughout its
mission, which hopefully is going to last the next ten years or so. After that, Webb
will be integrated on top of the Ariane 5 rocket and encased in its launch fairing.
And liftoff on December 22nd. Fingers crossed. Anyway, thanks for watching,
and I'd also like to thank my Patreon supporters for keeping Launch Pad Astronomy going. And
I'd like to welcome Richard Baker, Dushyanth Inguva, Dallas, and L.T. Marshall as my newest
supporters. And if you'd like to jin me on this journey through this incredible universe
of ours, well, please make sure you subscribe and ring that notification bell so that you
don't miss out on any new videos. Until next time. stay curious, my friend.