If we could turn back time....

[Workingman]

Well, we can, in a strange sort of way.

The James Webb telescope lifted off on Christmas Day and it is now through its initial set-up stage. Soon it will head off into the space between Earth and Mars, so dark and cold it will be unaffected by any atmospheres. It can look back to the time just 100 million years after the Big Bang some 13.7 billion years ago. Think of that. The dinosaurs ruled Earth for 250 million years. It is 100 times more powerful than the Hubble telescope, and we have all been amazed at the images that has sent back.

It has the ability to scan the atmospheres of planets many hundreds of light years away to try to detect gases that could only come from life (in some form) being present.

The search for ET is on!

[Suff]

It is a pretty incredible piece of equipment. No wonder it took so long and at such cost.

The deployment timeline video is here

https://youtu.be/RzGLKQ7_KZQ

It will take about 30 days to reach the L2 orbit, but only took 3 days to pass the moon.

The L2 orbit allows it 24x7 operation and 24x7 communication with Earth. Something Hubble cannot do.

The mirror itself is incredible. For those who know thermal imaging systems, the temp difference between the hot side and the cold side is 315C.

I was once told about the calibration of the challenger tank thermal imaging. The tank was set up in a 100m long cold hangar and the imager was exposed, then one drop of warm water was put in a glass of cold water. The entire glass became visible.

The JWST is millions of times more sensitive. What it sees is going to be groundbreaking and, as WM says, the hunt for ET is certainly on.

[Workingman]

The next step is unfurling the heat shield to keep the telescope super-cold and in its operating window. It will take a few days to get the tennis court sized membranes in place, then it's off to its observation position and final tuning and testing - about 1.5 million kilometres away.

We should get to see what it is 'seeing' around May or June.

I cannot wait.

[Suff]

Heat shield is fully deployed, the secondary mirror is deployed, both main mirror arms are turned around and the mirror is fully deployed.

From NASA

Webb will continue to travel to the second Lagrange point (L2) for another two weeks, at which point it will enter a large orbit around the L2 point. The following five months will be used to cool the telescope to operating temperature, fine-tune the mirror alignment, and calibrate the instruments.

[Workingman]

Yes, I clocked the mirror deployment. We now have till the end of May or early June, hopefully NASA will release some early fine-tune images as a taster.

[Suff]

Yes I was hoping that too. However 5 months is not the end of the world.

Keen to see just how good the resolution is. It should be at least hundreds of times better than Hubble. Although it does "see" in a different frequency so the results may be a little different.

[Workingman]

Images will be colour-corrected so that us mere mortals can 'see' them. Astronomers and Cosmologists will see them as they are - red shift, infrared. However, views in the visible spectrum will still be useful to us all, just as they have been from Hubble.

We will be amazed!

[Suff]

Current status

Individual Mirror Segment Movements
Actuator testing and individual mirror segment deployments

Nominal Event Time: UPDATE: Launch + 18 days (Jan 12)

Status: Ongoing

The primary mirror wings are now fully deployed and latched into place, but the individual mirror segments remain in their launch configuration. This operation is a multi-day, multi-step activity to activate and move each of the 18 primary mirror segments and the secondary mirror from their stowed launch configuration to a deployed position ready for alignment.

The 18 primary mirror segments and secondary mirror are adjustable via six actuators that are attached to the back of each mirror. The primary mirror segments also have an additional actuator at its center that adjusts its curvature. The telescope's tertiary mirror remains stationary. The primary and secondary mirror segments will move a total of 12.5mm, in small increments, over the course of ~10 days to complete each segment's deployment.

After all individual mirror segment deployments are completed, the detailed optical mirror alignment process begins which is about a 3 month process. In parallel, as temperatures cool enough, instrument teams will turn on their instruments and begin each instrument's commissioning process.

Temperatures



a) Sunshield UPS Average Temperature (hot side: Sunshield Structure)
b) Spacecraft Equipment Panel Average Temperature (hot side: Spacecraft Bus)
c) Primary Mirror Average Temperature (cold side: Mirrors)
d) Instrument Radiator Temperature (cold side: ISIM)

Hot Side
55C a
11C b

Cold Side
-200C c
-201C d

Progressing well.

[Suff]

Status: Complete. Webb is in L2 Orbit!

[Workingman]

JWST is now parked at L2 and for the next few months it will have its instruments and mirrors, primary and secondary, calibrated to the nth. This is where it will sit for its working life.

Some systems are already at its operating temperature of -230 ºC, so just a few more months to wait. It's only 1 million miles away so no problem adjusting them.

L2 is a Lagrange point. They are points of equilibrium as the Earth orbits the Sun and there are five. Worth looking up.