Monday, November 24, 2003
Happiness is a warm gun.
...well, a warm Stirling engine, anyway. Just before lunch we re-charged Nancy with 24 atmospheres of nitrogen (unfortunately there seems to have been a slow leak overnight) and set the automatic start routine in motion. On the first attempt the flame lit almost immediately (so running out of fuel hadn't been the problem earlier this year!); on the second attempt the burner ramped up as it should, but the mixture was not quite optimum and the flame went out again; and on the third attempt she whirred into life and was soon producing over 800 watts of electrical power. There didn't seem much point in hanging around after that so we switched the engine off and went to lunch. The only worry was that Nancy did a rather inelegant belch as the coolant first started to circulate, which could indicate an internal nitrogen leak.
After lunch we charged the second Stirling engine, Sid, with nitrogen. This time, the engine leapt into life on the first attempt. However the power output was much less - just 330 watts, and over the next half hour proceeded to drop to alarmingly low levels. I've put a new evaporator in Sid. With any luck this will fix the problem; tomorrow we'll know.
Nevertheless, having both Stirling engines up and running is a major triumph. There's still a concern about whether they are holding pressure properly, but apart from that it seems like they might both be as good as new. Not only that, we also inadvertently tested the room temperature control system, which works by blowing warm air out of the AASTINO. Because the AASTINO is, in principle, completely sealed, this forces cold air to be sucked in. I had set the Eurotherm temperature controller to +30C to ensure it didn't spontaneously switch on. However, with Nancy going full tilt the room soon hit that temperature, with the result that the two exhaust fans suddenly leapt into life. This would not have been so bad except that I had earlier put plastic bags over them to help keep the room warm. The sudden, ear-shattering noise of two 6-inch fans trying to swallow a couple of plastic bags was quite extraordinary. My immediate thought was that a Twin Otter was coming through the side of the AASTINO, and it took me a second or two to recover enough composure to dive for the "off" switch.
The day had actually begun distressingly early, as the solar eclipse started at 6:30 am and we wanted to be ready in the AASTINO to film it. Being astronomers, we were able to predict the timing of the eclipse to the nearest second - simply by looking it up on the web. Unfortunately the days are long since gone when the astronomers could convince the emperor that the sun was being swallowed by a gigantic dragon, and that only payment of handsome royalties (to the astronomers of course) would persuade the dragon to regurgitate the sun and bring daylight back to the earth. If I had thought I could get away with it I would have demanded that, in return for us agreeing to bring sunshine back to Dome C, Jean Louis should be immediately seconded to the UNSW Antarctic Group.
The eclipse was quite spectacular, with about 90% of the sun covered by the moon. We photographed the eclipse itself, photographed other people photographing it, and just stopped short of photographing people photographing people. (We probably would have gone that extra step had it not been for the fact that it had been -51C overnight, and was not greatly warmer at 6 am.)
We then sent the images back to UNSW where they are by now hopefully adorning our web page. It turns out that Antarctica was the only part of the globe to get a decent view of this eclipse, so we were really rather lucky to be here.
Meanwhile Anna has been locked in mortal combat all day with the Supervisor computer, and appears to be coming out on top. She's very close to explaining why Summit - one of our main science instruments - spent inordinate amounts of time during the year twiddling its thumbs when it should have been taking data for us.
After lunch Gerhard shifted our tent back about 2 metres to allow cleaner airflow around his precipitation monitor. This is important because he wants to measure the natural snow fall, not the snow fall that is induced by wind-blown turbulence. He then declared that he was bored (his instrument was working just fine and there was nothing more really to be done), and offered to help out with the AASTINO. We suggested he might like to write a script to analyse the Summit data, and he went off and spent several hours writing an amazing script for us that does a prefect job of telling us just exactly what the instrument is up to, and has been doing in the past. He even claimed to enjoy it.
What a guy!
Beatles scholars may feel I could have done considerably better with the title. However it was such a great song, one that was rendered particularly poignant when, shortly being shot dead in New York, John Lennon explained that (amongst whatever other interpretations might be placed on the lyrics) the song was intended to ridicule US hand-gun laws.
I briefly considered the Rolling Stones' "Start me up" as an appropriate summary of the day's events vis-à-vis Stirling engines. However that song has forever been destroyed by Microsoft, who reputedly paid over a million dollars to use half of it in the launch of Windows 95. This in itself would not have been so bad had Microsoft had the decency to use the whole song in the advertisement, as it includes the particularly appropriate line: "...you make a grown man cry."