Antarctic Astronomy Diaries 2003/04


13 November 2003
14 November 2003
15 November 2003
16 November 2003
17 November 2003
18 November 2003
19 November 2003
20 November 2003
21 November 2003
22 November 2003
23 November 2003
24 November 2003
25 November 2003
26 November 2003
27 November 2003
28 November 2003
29 November 2003
30 November 2003
01 December 2003
02 December 2003
03 December 2003
04 December 2003

Sunday, November 30, 2003

Do you want to know a secret?

Today is most likely our last full day here, so we tried to tie up loose ends and finish at least what we perceived to be the most important of the remaining tasks. One such task was to pack up the electronics box of the Sodar, ready to ship back to the manufacturer for refurbishment. This means that the "AASTINO bird" is no longer singing, and an unaccustomed silence has descended upon the Station.

When we came to pack the electronics box up, we discovered that all of the little bolts that hold the cover in place have gone missing, along with many of the bolts that hold its internal organs in place. I didn't feel I could ship it all the way to France (even in the protective envelope of DOG the suitcase) in such a dismal condition, and of course we had no suitable spare bolts in the AASTINO.

I therefore went to the mechanical workshop, where they were in the process of repairing a bulldozer the size of a small house, and asked if I could have a handful of 3 mm bolts. This request was treated with a palms-in the-air gesture of "we only do real bolts here", and I was shown a box containing some bolts as big as baseball bats. I felt as if I'd just walked into a rough outback pub and asked for a lemon squash, and made a hasty exit.

As it turned out, I was able to attach the cover, and the innards, using cable ties. (I wonder what we ever did before cable ties were invented?) We then wedged the solar electronics into the suitcase, closed it up tight, and it's now ready to go.

Lunch was the usual relaxing Sunday feast, a highlight of which was "escargots". I had never tried them before, and have no wish to again. We were issued with special snail-eating tools, consisting of a pair of snail-shaped forceps with which to hold the shell, and a narrow fork for extracting what some people consider to be the edible part of the creature. To be honest it didn't taste that bad, but on the other hand neither would anything else that was drenched in Jean Louis' garlic and parsley sauce.

By mid-morning the wind was blowing strongly from the direction of Terra Nova Bay, and the sky was completely cloudy. This is the first day of really bad weather we've had. It's not actually very cold, but the wind and the overcast sky makes it very difficult to work outside. We're glad we moved the flags yesterday! At 17 knots (about 35 km/hr) the wind is about as strong as it ever gets here.

Meanwhile, we've succeeded in installing the big ceiling-sweep fan in the AASTINO. It works beautifully, but at full speed it rivals the blast from a Twin Otter propeller. We've therefore set it on low, and left it so it can be switched on and off remotely from UNSW. We've also cordoned off the area immediately around the fan, in the hope that Tony won't lose too many teeth before he figures out how to switch it off.

The AASTINO is now once again on its own, awaiting the arrival of Tony around mid December.

So, do you want to know why the AASTINO stopped? To let you in on a secret - so do we. There's still a few uncertainties, but we think the sequence of events was the following:

1. On 28 June, the Dallas bus stopped working. The Dallas bus, you'll recall, is the attractively coloured green cable that runs around the AASTINO, talking to little boxes along the way that measure things and switch things on and off. It probably stopped working because of a "memory leak" in the Supervisor computer, which I am lead to believe is something that computers get from time to time but is relatively easy to fix. Now, the Dallas bus had crashed a few times before, without any bad consequences, and we weren't too worried about it.

2. However one of the things the Dallas bus does is to turn the fans on that keep the batteries warm. The day before the Dallas bus crashed, the batteries had cooled close to -40C, even with the fans on.

3. Without fans, the batteries probably froze within 48 hours.

4. On June 30, the Stirling engine (Nancy), which until then had been merrily charging the batteries for the past six months, probably freaked out when it suddenly found that 120 kg of batteries instantly disappeared. I certainly would under those circumstances. Nancy stopped running.

5. It's not inconceivable that Nancy produced a voltage surge at this point which blew up the Iridium phone power supply. Certainly the Iridium was non-functional from this moment on.

6. With frozen batteries and both engines stopped (Nancy was probably still perfectly functional, but could not be restarted on account of the batteries being frozen), the AASTINO basically ground to a halt until sunrise, which was in late August.

7. Once the sun was up for a few hours per day, the batteries thawed. >From that point on, the AASTINO was up and running again. However, we had no communication with it because the Iridium phone had blown up, the web cam was not taking pictures because if its own disagreement with its power supply, and the Sodar was not taking data because we'd programmed it not too. Had the Iridium been working we could have corrected most, if not all, of these problems. Fortunately, the sub-millimetre instrument Summit woke up as intended and, unbeknownst to us, set about acquiring useful data.

While we can support most of the above story with facts (which I shan't bore you with), there are elements of pure speculation in there. For example, it's possible the engine stopped first, and then the battery froze. However, if Nancy did stop, she did so in a way that none of the engines has ever done before, and there seems no particular reason why she should have stopped at that time.

And, being Sunday, it's time for another photo essay:

Luigi. This is a rear view (I think) of the Station Leader, Luigi.

Crane. If you need a "bigger hammer" at Dome C, there's always one
The Twin Otter is the standard means of getting around the Antarctic plateau.
Roughly 1200 litres of Jet-A1 is needed to get back to Terra Nova Bay.
Master chef extraordinaire, in front of Concordia.
With flags, precipitation monitor, and tent.
The "ground crew" await the arrival of the Twin Otter.
"Urggghhh!!!...not bad." was the verdict.
The solar eclipse (somewhat saturated) over Concordia.
The number two chef demonstrates correct snail etiquette.

Powered by Blogger