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
 
Contact:
| 
