Saturday
22nd November 1997 -
Taking things apart
From
John Storey.....
We,
and others, have mainly been taking things apart. Things are
much less assembled than they were, say, 24 hours ago. Nevertheless,
this is mainly a good thing.
A
couple of emails ago, a few lines got deleted from the middle
my message for reasons known only to the computer. I was saying
that I thought it worthwhile to completely rebuild the electronics
during 1998, as it has taked a real beating. We could take
the opportunity to add a few refinements in order to make
trouble-shooting easier.
Then
for no apparent reason, the computer decided you'd had enough
of that and cut straight to the middle of a story about how
Ant had galantly climbed the G-tower and attached a pulley
so we could haul the crane up. My musings about how cranes
are wonderful apart from the fact that you have to get the
crane up the tower in the first place got truncated.
Great big cranes need less big cranes,
Their
altitude to heighten.
These
little cranes need smaller ones,
And so ad infinitum.
(With
apologies to the person who wrote something similar to explain
microthermal turbulence and astronomical seeing, having ripped
the idea off from someone who was talking about fleas.)
Anyway,
to get the AFOS off the G-tower we need a crane, and the crane
is no longer at the top of the tower because it was removed
at the end of last summer (using gravity assist). So, we rigged
up a rope and pulley and proceeded to the haul the crane up
to the tower. About six inches. After a lot of aerobics we
came to the conclusion that the task was physically impossible,
and set off to find - yes, you've guessed it - a Sprite, so
we could tie the rope onto the bumper bar (or equivalent)
and haul it up. Fortunately we couldn't find a Sprite, which
is a good thing, because the pulley was only tied to the hand
rail and, as the Fluke pointed out, we would have simply pulled
the handrail off the tower had we tried.
So
that left us with the AFOS at the top of the tower and the
crane at the bottom, when really we wanted it the other way
round. We contemplated tying the rope aroung the AFOS, passing
it through the pulley and using the crane as a counterweight,
but only briefly.
It
turns out there are two ways to get a big crane up a tower.
One is to use a little crane, and the other is to use a REALLY
BIG CRANE. It turned out that the station crane was going
out to the dark sector yesterday evening to assemble an AMANDA
drilling rig. It was therefore arranged that it would not
only take GRIM down from SPIREX, put the Abu platform up on
SPIREX, and put the G-tower crane on top.
It
was supposed to come at 10pm but eventually started around
3am. By then I'd fallen asleep and took no part in the proceedings,
but I don't think anyone noticed. Ant and the SPIREX crew
worked till 4 and got the whole thing done.
This
morning the AGO service crew arrived and started pulling the
TEG apart. They are serious about getting it going, and have
replaced the platinum beads and the thermoelectric modules.
The TEG is spread over the entire floor of the AASTO. Ant
and I have made a strategic retreat to the MAPO building until
the atmospheric rockwool levels subside.
Now
that the weather is a little better, Hercules flights have
resumed. This makes life seem little more normal, as we're
no longer isolated from the rest of the world. The South Pole
program is weeks behind schedule, so they're scheduling 6
or 7 flights per day. However, typically only two are successful.
Because
the Air National Guard are now flying the planes instead of
VXE-6, the option of using JATO (Jet Assisted Take-Off) is
now available again. Ev says they plan to use it on one of
the upcoming AGO service missions. This is important to us
as eventually we want to put the AASTO on the moon ^H^H^H^H
Dome A.
Walter
Tape is spending a few weeks here. He is the world expert
on ice halos, and is continuing his studies this season. Maybe
I already mentioned that.
Today
the wind was down to 8 knots, so with the crane mounted atop
the G-Tower we tackled the task of bringing the AFOS down.
This was reasonably straightforward, but slow, cold and painful
because the wind decided to pick up again as soon as we started.
The AFOS is now sitting on a sled at the base of the tower,
until such time as we can get some space in MAPO to disassemble
it and pack it into a crate. I hope it doesn't rain tonight.
For future reference, the nut that turns the crane is 1 1/8
inches. I mention this to save future generations of Antarctic
astronomers the frustration of carrying half a workshop's
worth of ring spanners up the tower, only to find that none
of them fit.
Today
we also discovered that the cable we need to instal to run
Abu, and which was ordered weeks ago, is sitting in Yerkes.
It is probably not very useful to them there. However, we've
found a roll down here that will probably do instead.
The
VIPER (Cosmic Microwave Experiment) was unpacked and it was
discovered that the waveguide has sheared off the inputs to
the preamplifiers, no doubt increasing their noise figure
a tad. It's increasing unlikely that VIPER will run this year.
Another
thing that's unlikely to run is the hard disk of the "super"
computer. I plugged in the other 800MB drive and it made happy
little disk humming noises. (This despite the fact that Ev
Paschal who shall remain nameless *dropped* it off the shelf.
Its fall was broken by the fact that it landed on the keyboard
of my Mac. Note to mcba: Macs *do* have their uses) The super
still wouldn't boot from it, but I didn't investigate further
becaue the monitor wasn't plugged in. (It's in a plastic bag
to keep the rockwool out of it). The noise it makes is quite
unlike the mating-wasp noise the original one makes.
Ant
volunteered for "house-mouse" duties today, and
spent a couple of hours washing dishes. His skills were greatly
admired by the cooks, with the result that I believe he will
receive the runner-up award of house-mouse of the week. The
cooks have given us a packet of bi-carb soda to fix our electronics
with. They seemd to think this was perfectly normal, but then,
we are at 10,000 feet.
Al
Fowler and Nigel Sharpe didn't arrive today, which is just
as well becasue we still have about a week's work to do before
we're ready for them.
Micahel
Ashley sent a sample of the stepper motor software to us,
in reponse to our various unsubtle hints that it would be
nice if a few little changes were made to it. This code, you'll
recall was written by a professional programmer. I've come
to the conclusion that professional house painters and professional
programmers belong to the same union. Certainly the code looked
like it had been written by a house painter, probably the
one who painted our carport brown when we wanted it left white.
The
section of stepper-motor code that worried me most was
If
(someone is in the AASTO watching)
{
work properly};
Else
{ stuff up really badly }
Al
Harper has asked to be kept informed of what we're doing here,
so I will add him to this mailing list until such time as
he screams for mercy.
John
 
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