Antarctic Astronomy Diaries 2002/03

   

   
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Sunday, January 19, 2003

The Dallas Lama

The day dawned white and overcast (as opposed to grey and overcast) with winds of up to 11 knots (~20 km/hr). It's also snowing a bit - not big fluffy snowflakes but gritty little ice particles that are sometimes called "diamond dust". The wind makes it feel a lot colder, and is all the more biting because we're not used to it. It seems like a gale (and it makes our flags fly nicely!), but in reality it's about equal to the average wind speed at South Pole.

The light makes a big difference to the way the station looks. You might think that snow is snow and just basically white, but it's remarkable how the appearance changes. With a clear sky and the sun low (as it is most of the time), the sastrugi are highlighted with bright facets and dark shadows, and the ice crystals sparkle from different angles as you walk past. When the sun is higher, the surface is starkly white and the surface features are flattened out. Today, with the sun behind clouds, the sky and the ground blend together into one big fluffy ball of cotton wool.

The bad weather is apparently the edge of a major storm that has hit McMurdo - the big US station on the Antarctic coast. No planes are flying in or out of there, so the Twin Otter that arrived here around lunch time will stay here until conditions improve. When it does leave, possibly tomorrow or Wednesday, it will take me with it to McMurdo, on the start of my journey home. Unfortunately, that will bring my diaries to end, as I return once more to being a mild-mannered professor of physics. With any reasonable luck Tony and Jon will keep us all up to date on what is happening back in the AASTINO.

For now, however, I'm still at Dome C, and we're largely engrossed in getting all the electronics to work. Our big challenge today as to get the Dallas bus operating, and the wakey-wakey board working so that the Supervisor computer would be properly power-cycled. The latter involved modifying an existing wakey-wakey board, and jollying up the 1 Hz oscillator that drives it. This all would have been made a lot easier if we'd remembered to bring any electronics components, and if aliens hadn't made off with every single one of our 6,100 spare resistors. (We're working with automotive wire strippers, a few automotive crimp connectors, some diodes Tony salvaged from the old Icecam battery pack, and two boxes of very large and unlabelled resistors the Station crew found somewhere.)

By late afternoon the Wakey-wakey board was running nicely and ready to install. (Development and testing time was speeded up by a factor of 1,000 because Tektronix had thoughtfully provided a 1 kHz output on the front panel of the oscilloscope - no doubt with exactly this eventuality in mind). Although it all worked perfectly on the bench, installing the Wakey-wakey board into the Supervisor computer resulted in a shower of sparks, a brief flame, and lingering smoke chillingly reminiscent of the great SODAR disaster.

Fortunately, no lasting damage was done, except perhaps to my pride. In order to improve the cooling of one of the electronic witches, I had mounted it on a conducting piece of the circuit board, which made that part of the circuit board "live". This would have been fine - if I hadn't then connected this live piece of circuit board to the chassis with a dirty great bolt.

My other great feat of incompetence today was less spectacular but more amusing for the onlookers. Making an insulating spacer by carefully cutting a piece of sleeve off one of our automotive crimp connectors, I sliced through the final piece of plastic which went "ping!", ricocheted off my right ear and disappeared. After I'd made a futile search of the floor and surrounding areas and resigned myself to having to make another one, Jon and Tony let me in on the joke - it was stuck in my beard.

Another moment of excitement occurred when the Station power went down. We dug out our inverter and were just about to demonstrate our total independence from the Station power when, unfortunately, it came back on again. In truth, all we're using Station power for is to run the computer monitor, soldering iron and oscilloscope. The two solar panels, and Sid the Stirling engine, are providing more power than we can use.

The first webcam imageMost of the day was spent "dangling Dallases", i.e. daisy-chaining together the little circuit boards that will measure temperature, fuel level, solar panel current and so on, and also switch on and off the room circulation fans, some parts of the engines and other important things. The "Dallas one-wire bus" is a wondrous thing that allows all these things to be done with just a single wire. This, in principle, simplifies our lives a lot. However in practice it's a trifle tricky to get working properly - especially when armed only with automotive electrical tools.

To make things a bit more reliable we're planning to use the webcamera to switch the engines on and off. We think this is a good idea, but then again we are at 13,000 feet and it might be wise to review the concept tomorrow - after a good night's rest.

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