South Pole Diaries 2001/02

   

   


Thursday 24th January

From John Storey.....

Today the weather was truly glorious; the first really clear and calm day we've had since arriving. Even though the temperature dropped to -32 C, the wind is so low (just like at Dome C) that it is not at all unpleasant outside (in appropriate clothing, of course!) When the sky is completely clear it has a dark blue appearance I've never seen anywhere else in the world.

The first thing I did once I got out of bed was to log on to the Stirling engine to see if it was still running. As it turned out, it was loping along with consummate ease.

Just before I walked over to the AASTO this morning, the British Antarctic Survey Twin Otter took off, leaving a white vapour trail along the skiway. The vapour (actually ice crystals) hung in a long, low white cloud for at least thirty minutes, as it gradually drifted across the station. As it passed in front of the sun it created two beautiful sun dogs, making it easy for me to forgive it for placing me in partial shadow for a while.

Speaking of dogs, I have now brought out my trusty Macintosh PowerBook, called "poodle". Poodle is getting a bit old for a computer (5 years), and this is the fourth trip to Antarctica he has accompanied me on. Sadly, it may be the last, as he is a little too old and slow to feel at home in the snazzy new station network at South Pole. Still, he's indispensable for controlling our instruments via telnet, checking on the webcams, and generally keeping me company. Over the next couple of days poodle and I will check the instruments as best we can, and ensure that they are fully remote-controllable from UNSW.

Now that everything is more or less working properly, I decided to waste another couple of hours trying to fix the Supervisor computer. After spraying the keyboard connector with every ozone-destroying chemical I could find and making not the slightest difference, I decided that a cracked solder joint was the only remaining possibility and stripped the stupid machine down to the motherboard. After carefully resoldering all the connector joints and checking their resistance, I was rewarded with a machine that is as sullen and unresponsive as it ever was. Enough pussy-footing around - tomorrow we're talking major surgery (and without an anesthetic).

Duane was able to get enough data for another chapter of his thesis this morning by simply pushing the "Autotune" button on the Eurotherm temperature controller. This invites the controller to force the room temperature up and down in a series of oscillations while it carefully measures what happens and sets its various gain constants and things appropriately. Up until now we have been allowing it to use the constants it set for itself while we were testing it at UNSW. As far as it was aware it was still in the lab at UNSW trying to keep constant the temperature of a small cardboard box with a couple of light bulbs in it. Under the circumstances, I think it was doing a remarkable job.

For the rest of the day it was fiddly, unrewarding little jobs like sorting out what to take back to UNSW and trying to re-learn MS-DOS. I'm also trying to train myself not to put the floppy disk into the Zip drive, as it doesn't fit properly.

We decided that the exhaust from the Stirling engine is too cold by the time it reaches the top of the exhaust pipe (you can comfortably hold the copper pipe with your hand ). Given that the outside temperature may drop another 45 C by mid-winter, we run the risk of freezing the exhaust and choking it off. Duane was able to find some fibreglass pipe covering, and we now have the pipe insulated to within a few centimetres of its tip. It's still surprisingly cool. The exhaust (which is just water vapour and carbon dioxide) leaves the engine at 300 C, but freezes instantly as it hits the cold Antarctic air. Here, it's just the water that freezes. When we move higher up the plateau, it will be cold enough in mid-winter to freeze the carbon dioxide, too.

The bulldozers are being kept busy around the clock here trying to remove the snow drifts that have accumulated over the past couple of months. Webcam devotees will have noticed that the AASTO is slowly disappearing behind a large mound of snow. The AASTO is actually standing on four legs about a metre and a half high, but it doesn't look that way anymore. The path from the Dome (where we eat) to the Dark Sector about a kilometre away (where all the astronomy experiments are, including the AASTO) crosses the ski-way about half-way along its length. To avoid any unfortunate and messy conflicts between people and aircraft, there are two flashing red beacons that are turned on if an aircraft is coming in to land or taxiing for takeoff. I always take these beacons very seriously and, even if they are not flashing, take a careful look up and down just in case. This morning I was halfway across the ski-way and looked up to see a dark shape emerging from a cloud of wind-blown snow and water vapour not 100 metres away. For a moment I was gripped by stark terror, only to be relieved seconds later to see it was merely a bulldozer grooming the ski-way for the benefit of the next few aircraft. While I am confident I can outrun a D4 Caterpillar (especially when it's dragging a 20-tonne groomer), I don't like my chances against a Hercules. They don't stop very well when they're on
skis, either.

John

 

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