South Pole Diaries 2000/01

   

   


Sunday 10th December 2000

From John Storey.....

I awoke this morning at 5 am after a strange dream in which I had just finishing giving a lecture and started on question time. The first question was from someone wanting to know how to write some complicated expression in LaTeX. He was definitely asking the wrong person. While trying to think up a plausible answer it suddenly occurred to me why our instrument was recording a huge amount of noise at one particular position of the mirror. It just had to be that stepper motor again, oscillating back and forth about its requested position and unable to settle down because we'd turned off its holding current. All that we had to do was to persuade it to be content with getting the position nearly right, and to stop being so obsessive about the last decimal place or two.

Sure enough, with this more laid-back approach to life, the stepper motor has performed faultlessly all day and all our data points are nice and clean.

Meanwhile Michael Ashley has come up with some good ideas about the "Bored Eric" problem. These, together with our own experimenting, mean that we can now actually walk away from Summit for hours at a time and be confident it is still recording the sky for us. Paolo has written a macro called "nice_dreams" which allows us to catch up some sleep while Summit goes about its business of collecting data.

The remaining problem concerned the ADC board that we had blown up on the very first day within the first hour of switching Summit on. The only essential function we had lost was the ability to turn the chopper motor off under software control. This we had worked around by installing a manual switch, and now all that could go wrong was the mains power could fail in the middle of the night, switch back on again, and cause Summit's chopper to fry itself. Power outages are bound to occur, if only because the two diesel generators are swapped over once a week. In the end we decided to leave the faulty ADC board in place, and to rig up a magnetic switch that would keep Summit switched off should the power fail. This appears to work well, and means there is one less thing for us to worry about.

We could replace the ADC card, as we have a spare, but I am loath to do so. For one thing, we are not well set up for the job and risk further static damage to the PC/104 computer. Secondly the PC/104 computer hardware is a stupid fiddly thing designed by ex-stepper-motor engineers. Thirdly, it's sitting outside in the electronics rack where the average daily temperature is around -33 C.

Today being Sunday we got on with a few housekeeping jobs. I did my laundry, using one of those amazing European washing machines that take about four hours to wash a pair of socks, only to reduce them to their component molecules during the spin-dry process.

Italian air force C130 at Terra Nova BaySadly, it was also time to organise my departure from Dome C. My itinerary now is complicated by the fact that I will fly to McMurdo as an Italian, metamorphose there into an American, finally to revert to being an Australian once the NSF have taken me by C130 to Christchurch. All this was negotiated over the HF SSB radio, a process that involved using the powerful Rohde & Schwarz transceiver with the crook antenna to talk, and the weaker Motorola transceiver with the good antenna to listen.

Chef Jean-Louis threw his all into Sunday lunch, handsomely exceeding even the high expectations of the station. It was the usual sort of affair: saumon fume (smoked salmon)on crisp toast on a bed of fresh salad for starters, followed by a pasta course of ravioli and then sauteed NZ mussels with herbs accompanied by an excellent unwooded Australian chardonnay. The main course was roast crocodile, with a good Coonawarra cabernet/shiraz. Dessert was ile flottante, which is a soft meringue floating in caramel sauce and drizzled with toffee. The Berlucchi was, according to Paolo, not one of the better vintages, but to my palate this Italian methode Champenoise wine was perfectly acceptable complement to the dessert. Lunch slowly wound down over a fresh fruit platter with Kiwi fruit, assorted cheeses, individually made espresso coffee and biscuits.

After lunch we checked the email and decided to carry out some more tests. We took a break to watch our colleagues, Jean-Michel and Karim, from the University of Nice launch a weather balloon and radiosonde. They have about 11 balloons, and their next flights will include microthermal sensors to measure the turbulence of the atmosphere. Launching the balloon invovles first inflating it with helium until it can lift the 375 gram weight it is tied to---in this case a can of VB beer. Next the batteries of the balloon payload are activated by dunking them in water for a few minutes, and finally the payload is swapped for the VB and away goes the balloon. The signals from the payload are received in the balloon-launch tent, and consist of jolly little tunes not unlike the ones our sodar plays. The computer can then interpret these as temperature, pressure humidity and wind speed (which it gets from a little GPS).

After dinner I gave a science lecture in the Free-time Tent, using poodle to drive a 20-inch monitor (which was the biggest thing we could find). Being able to use Powerpoint avoided the need for Paolo to do street theatre and made for a colourful presentation. I think it went over ok; at least no-one wandered off out the tent saying "I may be some time..."

Around 10:30 pm we were taken on a tour of the new station by Augusto Lori, the station leader. The present station is really just a construction camp for the permanent facility, which will consist of two 17 metre diameter cylinders linked by a walkway. The cylinders will be three stories high; one will be the "noisy" building and one will be the "quiet" one. At the present moment one cylinder has the frame almost finished, and the foot pads for the second have been laid. Scheduled opening date is 2003, after which time Dome C will be ready for year round operation.

John

Coming Soon!