This morning, SEI, TMS, and SUS gave a cursory "approval" of their systems in order to proceed with chamber close-out tasks. So, after lunch, Margot and I applied First Contact to the ETMy-HR surface which will be pulled just before closing the door tomorrow. The order of events this afternoon (and late morning in order to catch the alog up):
Jim locked the ISI and put final touches on chamber feedthru cable routing.
Apollo+Joe+Gerardo had a viewport party at the BSC10/6 area.
Margot and I locked the lowest masses of the ETMy QUAD. Then we,
Secured the ACB locking bracket and used the wedge to swing it back and prop it into place. See notes on this in attached alog.
Attached the FC QUAD cone to the structure and sprayed FC (standard 3 coats) on the HR surface.
Removed the cone from the suspension. Finished FC layer reinforcement.
Removed the wedge from the ACB and restored it's nominal hanging position. Removed the ACB locking bracket screws.
Started stowing all left over bags of "junk" left outside of the chamber door on various table surfaces by SUS and every other team that visited this last month. If you're missing something (and you noticed), I took ownership of it.
Jim arrived and unlocked the ISI. The ETMy QUAD will remain locked during dome replacement.
Apollo started gearing up to remove walking plates from upstairs and crane the dome on the chamber.
Tomorrow's to-do list which Margot and I will do until the last step:
Inspect insides of viewports.
Adjust ACB to check magnet gap which may or may not have shifted slightly due to the swing back from today.
Clean the chamber, vacuum, etc.
Take final PCL swipes.
Blow various other optic surfaces. Or not.
Swap in final 1" witness optic on QUAD structure.
Check/Remove all tools.
Remove ETMy-HR with N2 blow.
Set and lock all 64 QUAD EQ stops and nuts, accounting for buoyancy.
Set QUAD BOSEMs to account for buoyancy.
Quick QUAD health check with DTT TFs.
Lay final witness plates.
Exit chamber.
Finish stowing everything around door and move it out of the way.
Put door on.
So, when we went to swing back the ACB and stuff the wedge into place, the wedge could not be inserted in the gap all of the way due to interference with the round balance weight attached on top of the baffle. We pushed the wedge in ~2/3 of the way which gave us ~2/3 more working area than we had with out swinging it back at all. Good enough. (Removing the round weight would have cause the balance of the ACB to be out of alignment so that wasn't an option.) Also, even though the locking bracket was engaded which provided some support to the down tube of the ACB, the ACB was still a bit "rickety" during this maneuver.
The first picture below is of the ACB wedge not quite installed as far in as it could. This meant that the screw holes to secure the wedge in place could not be engaged. ACB engineers must have anticipated this so they provided us with a "safety" chain which one could tie up "somewhere" such that the wedge doesn't come flying out at you if you bump the baffle while it's up. The chain was of limited length, so they best Margot and I could do was wind it around the post loosely a few times. Note, the wedge seemed wedged in well enough that it didn't budge when we did happen to bump the baffle a bit here and there with the cone work.
Also note, the ACB did not hang the same way after we restored it. Mitchell had to make some minor tweeks to the balance today in order to recover the correct gap setting for the magnets (specifically 0.09 inches! - Really? Not 0.08" or 0.1", but 0.09", huh!? Seems a bit tight given the grossness of both the swing back application and the shear size of the baffle... but what do I in SUS know.) In the end, as usual the ACB comes with in a few mm of the QUAD structure at the head of one of it's screws (see 2nd picture with red circle around it).