Hubble in trouble

JWST sun shield was unrolled successfully; probably the riskiest business. Secondary mirror unfolded. Primary mirror segments unfold next.

You have probably read that fuel remaining on board should suffice for 10 years. If we may get ahead of things a bit. You may have read that JWST has a refueling port, and so yes, some Musky mission might refill its tank someday.

In a different discussion group it was asked whether Hubble and JWST could take pictures of each other? Hubble lacks spatial resolution by a factor of at least 30 by my figuring. Even with all its lovely galaxy imaging, a 40-foot thing a million miles away is just too dang small. Looking the other way, JWST might just fill a pixel with Hubble, but that will never happen. Hubble is always 'sunward' from JWST, and the latter would never ever be aimed towards Mr. Fusion.

 

Looking far ahead, assuming JWST performs well, your irrepressible reporter imagines that a JWST companion telescope (to be named after a non-homophobe ) could be sent to L2 for interferometric astronomy. Work two together and dig down deep into micro arc seconds resolution.

L2 really is the place to be to look way out yonder. For a civilization not knowing how to actually go to places far away.

 

Not sure what the "non-homophobe" refers to.

 

Someone other than James Webb.
https://www.nature.com/articles/d41586-021-02010-x

 

Thanks for that info.

 

Was Jim REALLY homophobic is he merely accused of making statements in the 60's that are heretical by 2020 standards?

Maybe we should just name observatories after astronomers.......

 

It looks like the kind of story that refuses to fit that or any other artificial dichotomy.

Seems like the "lavender scare" was a bit of a big deal, and involved considerably more than people "making statements".

At the same time, there seems to be limited evidence on the question of how much JW personally had to do with it.

 

It wasn't far removed in time from Alan Turing's story.

 

There is plenty of context in @Trollbait link #84 if people are looking. In my opinion Webb did not mess things up at NASA, not enough to outweigh his science leadership.

I wish I had not mentioned the H word and just left squirrel herding to others, but too late now.

==
There are many notables who did wonderful things but who were also associated with things of their time that later seemed wrong. Fascists and racists and eugenicists and what have you. Tired of naming names though. On the whole it seems better to remember them for the good stuff and use the bad stuff to illustrate that civilization is making some progress. Learn from the past and what have you.

I anticipate that JWST and its scientific output will help with that.

Also the silicone coating on JWST sunshield makes the whole thing look very lavender. FWIW

 

JWST unfolding completed

https://www.nasa.gov/press-release/nasa-s-webb-telescope-reaches-major-milestone-as-mirror-unfolds

and I stole a GIF from someplace. Just for you

 

Are we theeeeeeeeeeere yeeeeet?

 

Almost there spatially. Being there thermally will take more time.

 

I think I'm seeing 75% spatially, 50% temporally, to L2 insertion.

Thermally? I'm not sure how to rate that. One particular sensor was likely about 300 K on the launch pad, and is down to 74 K now, with a final target of about 40 K. But with heat shed as black body radiation, at a power rate proportional to T^4, those final degrees could be really slow.

 

40 K sounds like the passive cooling for several instruments. But there is active cooling down to 6.7 K for one instrument, using a four stage refrigeration unit:

How Cold Can You Go? Cooler Tested for NASA Telescope

https://www.nasa.gov/feature/jpl/nasa-s-webb-telescope-will-have-the-coolest-camera-in-space

 

A day after I posted that, that sensor dropped to 72 K, then didn't move for several days. Today it went back up to 73 K. So reaching 40 K will take quite a while.

"Mirror segments" activity scheduled for today, but I haven't found an article to describe it. Don't know if this means the start of fine focusing adjustments to the mirrors, or if that activity waits until it is on station.

 

Looks like NASA updated the tracker on this today:

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.​

https://webb.nasa.gov/content/webbLaunch/whereIsWebb.html

 

The instrument system radiator is back down to 72. But the primary mirror, which was hanging out in the mid-80s several days ago, is suddenly down to 67 K. Maybe related to lifting the mirrors off their transport supports and vibration snubbers?

 

Orbital Insertion burn coming up shortly, 11 am PST or 2 pm EST.

LIVE! JWST Countdown to L2 Insertion Burn - James Webb Tracker! #NASA #WEBB

 

One would think that Jim would be big enough to have his very own thread by now.....

GLAD the origami theory-to-practice is working out!

 

I think we're still waiting for T[non-jinx].

Jinxology was not my best subject, so I'm leaving that call to somebody else.