The first layer has been tensioned.

First Layer of Webb’s Sunshield Tightened

That was quick!

https://blogs.nasa.gov/webb/2022/01/03/seco...ully-tightened/

Sunshield fully tensioned!

https://www.nasa.gov/press-release/sunshiel...gship-telescope

Finding this part of the mission very engaging but at the same time very tense given the impossibility of fixing anything that goes wrong!

There's a lot of coverage on this but little detail - does anyone know of any documents with detailed arrangement of the wires and pulleys they keep talking about for the sunshield?
TIA

There have to be volumes. There was a 5-year period between "assembly complete" and launch that apparently included a test in which some part of the shield malfunctioned/tore. There's a wiki page for the shield alone with some links: https://en.wikipedia.org/wiki/James_Webb_Sp...scope_sunshield

Some live coverage here, secondary mirror already deployed and about to be latched:

https://www.youtube.com/watch?v=21X5lGlDOfg

You can now watch a recording of the full one and a half hours of "James Webb Space Telescope: Secondary Mirror Deployment - Mission Control Live"

https://www.youtube.com/watch?v=-EnlaXnFcGs

I spent some time looking at the NASA Tech Report Server but didn't really find anything that had a lot of detail about the sunshield (AKA sunshade). It may be that because it's a somewhat separate system designed largely by a subcontractor, the usual publication paths don't apply.

https://ntrs.nasa.gov/api/citations/2020000...20200001556.pdf is a very high-level discussion but has no satisfying details and there are no references to anything about the sunshade, though it mentions a 1/3-scale test model of it.

Secondary mirror deployed and latched.
https://blogs.nasa.gov/webb/2022/01/05/seco...ment-confirmed/

I didn't find much if anything about the mechanisms, motors, pulleys, or rigging arrangements either. I did find a paper that talks about the analysis of the behavior of the shield and gossamer structures. http://www.ryanfellini.com/publications/08SS_Fellini.pdf Perhaps more will turn up in time..

Also wondering about re-tensioning the membranes mid-mission, if that's something that can be done, if it needs to be done..? Watched a video, it's spring loaded and self-adjusting over the upcoming years.

Thanks, I couldn't find anything in detail - shame as it must have had a great deal of work on this contraption.

Another question which may be dumb
In the photos the secondary mirror looks convex but intuitively wouldn't you expect it to be concave to focus the light back onto the instrument?
e.g. Mirror Photo Link

This may help.

Very useful, thanks

Perhaps counterintuitive, but AFAIK all three-mirror anastigmats ( https://en.wikipedia.org/wiki/Three-mirror_anastigmat ) like JWST, and all Cassegrains for that matter, have convex secondaries. The Gregorian configuration has a concave secondary, though.
https://www.telescope-optics.net/two-mirror.htm

Thanks, it makes sense when you see the light cone diagrams. According to your linked document, the Cassegrain design dates from 1672 so there's a bit of catching up to do for a telescope novice like me!