The clouds went in and out with the TSS problems. AO team discovered a problem with the Thin shell Safety System (TSS) that helps the mirror against the wind effects. One crate was not applying any TSS current.
Both Microgate and Arcetri teams at this point turn the system upside down and started bravely to act on the rear of the crates…
The currents setting of the TSS where slightly decreased in order to avoid a DC DC converter to go crazy. After that a cleaning is a must.
The system were restored in the working position.
… and finally verified all good….
At this point we can say good by at our Microgate friends that are going home.
The storm is finally gone, and the beautiful clear sky is back. The TSS is fixed too, and after we installed our gimbal mirror motors the W-unit is complete.
This (kind of lame) video shows our little W-Unit robot responding to a Board Setup command. This tells it to go to a set of pre-determined positions which makes it ready to operate.
At this point most of our urgent critical path stuff is done, and we are starting to relax a little. We have a few more days of ASM testing to do, and some mundane odds and ends in the W-unit to take care of, like cable management. We also plan to do some testing of our software interfaces with the telescope control system.
The PI got hit with a rock this morning. That’s how hard the wind was blowing. He’s o.k., and the wind has died down tonight.
I’ll let Marco update us on progress with fixing the TSS. For now here are a couple of pictures of the work being done there:
Laird and I finalized the alignment of the W unit tonight. It looks like none of the components shifted during shipping so we don’t have to re-align anything on the board – a big relief. We also took a set of readout noise measurements, with decent results. Things are as good or better than they were at Arcetri. For the AO-nerds out there, the CCD 39 (our WFS camera) is turning in around 9 electrons RON at 1 kHz frame rate, and roughly 4.2 to 4.4 electrons on our slow (~100 fps) mode. We had both cameras running and were modulating during these measurements, so we fell pretty good about them.
A few pictures of the WFS in the NAS:
Some good quotes from the last 2 days:
“It’s pretty hard to keep VisAO down for more than an afternoon.” (Jared Males, spectacularly wrong)
“No! I want this to be a bonding ritual between us – and you know we’re going to do this every time we come up here.” (Laird Close, after Jared whinged about taking the same measurement for the 427th time in the last year).
“My attiude is when something is unknown, take the conservative choice, so fix it.” (Armando Riccardi, the ASM man)
Man, the ASM seemed to work really well and the AO group continue testing the system all the day BUT at a certain point the system started whistling!!! All the actuators were disabled, the system powered off and the shell was safe against the reference body but it was still whistling at about 2 Khz!!!!
Microgate people found the problem on the TSS (Thin shell Safety System): a single crate, after a while, was not applying constantly the wind safety current and caused the shell oscillation
That crate was oscillating with few [nm] RMS movements:
On the Unpacking day 10 Microgate people will address the problem.
Sadly, Microgate people were forced to delay their flights…