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Sunday
- December 31, 2000
By G. Wilson
I've
been wanting to write this particular update for
a while. Tonight, I lay it all on the table.
You see, this is the last update of the year 2000
and in the spirit of reminiscing of days gone by,
and in light of the fact that TopHat is bound for
higher altitudes in a few days, I figure that this
is an appropriate time to reminisce about our journey
to build the beautiful and nearly flight-ready TopHat
telescope.
Truly,
this is an epic story. There are heros. There are
villains. It's been a long and exciting road. But
first, let me fill you in on our environs. McMurdo
is abuzz tonight with New Years Eve revellers. The
big party is supposed to be at New Zealand's Scott
Base - a short walk but long stagger from downtown
McMurdo. Adding to the excitement in the air is
the arrival of the icebreaker Polar Sea. Each year
in the summertime the sea ice north of the Ross
ice shelf melts away under the sweltering Antarctic
sun. The Coast Guard then sends in an icebreaker
to cut a shipping lane through the remaining thin
ice to McMurdo. Following the icebreakers are container
ships from the US bearing next year's food, heavy
equipment, and fuel. Also tailing the icebreakers
are killer whales looking for yummy seals and penguins
along the Ross island coastline. In fact, Jim has
a nice postcard of a whale breaching in the sound
just off Ross island ... yet another reminder to
keep your toes out of the water!
So
TopHat has been a long time in the making. Like
most innovative projects, the original experiment
was actually designed to be quite different from
what we have now. Instead of an on-axis spinning
telescope, we started out with a small telescope
designed to point at specific points in the sky.
Fortunately, during the "pointer" development, the
thought arose to build a much simpler telescope
that spun at a fixed speed on a fancy lazy-suzan.
Thus, the TopHat-Spinner was born.
I personally joined the project in the fall of 1997
with the directive to move to Chicago where the
top package was being worked on by the vastly experienced
Steve Meyer and two graduate students (Tom and Jeff)
who were wet behind the ears and itching to be bossed
around by a young postdoc. What a fall. The three
of us, with help from Casey Inman at GSFC and a
lot of guidance from the older folks, built circuits,
cables, and sensors and eventually integrated the
top system's electronics - the same set of electronics
that are at work acquiring data as I write. As
we cranked on the electronics, Dale and Eun continued
work on the nearly miraculous Indigo dewar and Tina
Chen slaved away over acid baths and implanters
to build our ultra-sensitive detectors.
The
spring of 1998 brought a new challenge for the Chicago
folks. NSBF was interested in launching a mockup
of the top package to investigate the launch and
flight dynamics of a 250 pound top-mounted payload.
Tom, Jeff, and I were asked to build a small instrument
to fly inside the mockup and deliver temperature,
pointing, and acceleration data to the payload hanging
below the balloon. This was a new experience for
all of us but with a great deal of luck and a spring
spent travelling between Chicago and Texas - punctuated
by 5 or six high speed, high volume, drives on the
open Texas highways at 3 am, we managed to pull
the flight off.
I was the beneficiary of two frequent flier tickets
on Southwest Airlines due to the incessant flying
between work at home and work in the field. Man
was I sick of peanuts. You can see a movie of the
launch of the GSFC built mockup on this web siteour
web site. Our travel experiences, we were soon to
learn, were only just beginning.
In the fall of 1998 we shipped out again for the
LDB qualification flight of our bottom gondola -
this time to Fort Sumner, New Mexico. What a beautiful
place. Fort Sumner is located in the desert west
of Albuquerque. I haven't spent much time in the
deserts of the southwest so, much like my current
trip, I soaked up the scenery while we prepared
the TopHat bottom gondola for launch. This time
we had great help from the actual builders of the
gondola: Bob Silverberg, Ken Rehman, Joe Novello,
and John Stewart - all of GSFC - and once again
we enjoyed great luck and had a successful test
flight. I'll always have good memories of that Fort
Sumner trip. Jeff and I learned about the fine art
of surveying and Tom learned valuable lessons about
hand carrying a set of duct-taped batteries through
airport security.
It was around this time that my soon-to-be fiancee
asked me if most physicists travel this much for
their work. Of course not, I assured her. With two
successful launches under our belts in 1998 and
the addition of James to our posse, we were due
for some serious karma payback in 1999. And pay
we did. Nearly the entire year was spent trying
to diagnose a particularly insidious and subtle
thermal problem with our rotation system while sequestered
in Goddard's building 7. Despite the 35.25 years
of experience we had helping us, we somehow survived
with our egos only slightly bruised and our attitudes
firmly intact. What is truly amazing about 1999
is that any of us ended the year still dating our
beaus after spending so much time away from Chicago.
That includes Dave Cottingham who originally had
graciously offered to let us sleep in his house
for a few weeks. Those few weeks eventually grew
to months and months and Dave, being the gentleman
and scholar he is, never so much as blinked.
The
year 2000 arrived with the Chicago crew back in
Chicago for a brief chance to collect our breaths.
We solved the rotation problem with the timely purchase
of a restaurant meat locker big enough to cool the
entire top package, beautiful detectors arrived
from Goddard and Wisconsin where they had spent
1999 struggling to overcome a nasty problem with
their detector-building setup (it was a bad year
for everyone!) and Dale and Eun put together the
first long-term working Indigo dewar. But home life
was not to last long for Jeff and James who, with
steely eyes and a bulletproof drive system, went
back to the thermal chamber at Goddard to face another
two months of integration and testing. Tom and I,
busy building more Indigo dewars at Chicago, later
joined them for a few weeks of beammapping in the
Goddard anechoic chamber.
At this point we were entering the final stretch
so spirits were high. Nearly the entire TopHat collaboration
met up in Palestine, Texas for our pre-Antarctic
integration and shipping of the telescope. Tom,
Steve, Jeff, James, Bob, Ed, Dale, Eun, and Dave
spent nearly the entire record-hot summer in Palestine
while I stayed behind in Chicago to build yet more
Indigo dewars. Work in Texas went amazingly well
with only one blown up dewar (which was quickly
repaired) and, a collaboration first, no trips to
the emergency room on the fourth of July. When it
was all over and all our equipment shipped out for
the ride to Antarctica, we all breathed a collective
sigh of relief. One more trip to GSFC for beammapping
and $75 spent at Wallmart for Antarctic supplies
later, we were Antarctica bound.
And
here we are, on the eve of a new year and (metaphorically
speaking) a new launch. It's been a long and interesting
trip so far. The next few days promise to be interesting
and exciting as well. We've learned a lot, laughed
a lot, and quite miraculously have suffered no divorces
in the meantime. Thanks to everyone who has helped
us get this far. We're bringing it into the home
stretch now so keep watching and keep rooting. We're
working hard to ensure that 2001 begins with a ...
well, a great launch!
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Friday
- December 29, 2000
By G. Wilson
Greetings
from the deep deep south once again. I am in a particularly
good mood this evening because I am writing with
a clean set of clothes, a generally clean outer
layer of skin, and a slightly dirty coffee cup that's
filled to the brim with hot Peets.
Never mind that TopHat is in particularly good shape
as we round out our pre-integration testing, it's
really the simple things that make the biggest differences.
Are we going to continue to count down the days
until our launch? When will that be? It's a bit
difficult to say.
We
have gotten most of our testing out of the way now
- there are still a few left to do - and we are
nearing the time when we will begin integrating
the telescope with the balloon. Once we declare
flight-ready, it is the weather's will that determines
when we launch.
Speaking
of the weather, we were privy to witness a beautiful
sight yesterday. The ATIC package, the other ballooning
group down here, was launched yesterday evening
at approximately 5:30pm local time. The launch was
simply amazing. The day started out and continued
to be completely overcast. I had even seen some
snow flakes in the morning before their roll out.
Well, that didn't stop them. Around 4:00pm we walked
out to the launch pad and stood in the chilly wind
as they blew up the balloon. The clouds and snow
provided very little for contrast as backdrops against
the balloon so if you took your polarized sunglasses
off, the bulk of the operation nearly disappeared
from view.
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The
ATIC experiment on the crane prior to being
taken out to the launch pad.
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Checking
the balloon prior to inflation.
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The
balloon in the process of being inflated.
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The
balloon just after release.
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After
nearly an hour of inflation, the spool capturing
the base of the balloon was released and the bubble
made a quick jump into the very still low level
winds. Like all balloon launches I've seen, it was
quite beautiful. The balloon resembled a very large
jellyfish as the helium pushed in waves against
the balloon material and it seemed to climb into
the sky much like a jellyfish swims to the surface.
Finally, after what seemed like minutes, the balloon
was over the launch vehicle holding the payload
and the gondola was released for its voyage around
the continent.
Fortunately for us, there was a fairly low cloud
cover which made for a memorable scene as first
the balloon and then the gondola slowly disappeared
into the puffy grayness. As I understand from the
local gossip, the flight is going well and the balloon
has so-far held a roughly fixed-latitude course.
Back
on the TopHat front, tomorrow we hope to move the
lower gondola over to the lab space the ATIC team
had occupied. This will allow us to spread our elbows
a little and get our solar panels mounted up for
a power test. The top system will spend another
day here in the lab while some finishing touches
are made on the light shield. That's it for now.
Check back often for my "Ode to Stalagmites" audio
file which will be done in two part harmony. I'll
be doing the number one part.
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Tuesday
- December 26, 2000
By G. Wilson
Happy
Holidays!
Every
once in a while I like to remind myself why I'm
here. Of course on the surface I am acutely aware
of it, since I see and touch TopHat every day. But
every so often it's healthy and useful to think
through the chain of events that has brought us
to Antarctica to do this experiment.
For those who read these updates to find out what's
going on down here (a dubious proposition indeed
given what I've written in the past), I'll devote
a paragraph to our status first. For those who are
just looking for the latest gossip about our younger
team members, you have come to the wrong place...
of course, I'll be delighted to tell you in private
though!
Overall our flight preparation is continuing very
positively. The cryostat is cold once again in the
flight configuration after our successful noise
testing and the telescope is in the process of being
buttoned up once and for all. Luck was with us today
and the weather cleared, allowing TopHat to be once
again outside on the berm spinning.
This
test was necessary after the last spinning test
revealed a partially occulted sun sensor. Fortunately
this was very simple to remedy and we are now getting
the cross calibration data with the various sun
sensors. I should also mention that this test is
being done with the main rotation bearing in its
flight-lubricated state. Jeff spent nearly all of
Christmas day and Christmas eve putting the bearing
into its flight configuration and buttoning up the
stationary part of the telescope. We'll have to
make sure he gets an extra orange in his stocking
next year!
Now
we find ourselves with flight day rapidly approaching.
I won't deny that everyone is starting to get a
little fire in their belly thinking about the big
day. And who can blame them? The majority of the
people here have devoted their working lives to
TopHat for the past three years. And some have been
working on the project for the past six years! After
all that time, all the weekends and nights spent
in the lab, we are simultaneously eager and apprehensive
about the launch.
So, for the remainder of this "update" I want to
remind everyone why we do what we do. The big picture.
I like to think about this because it makes muscling
through the rougher times a little easier. Thinking
about our raison-d'etre is also just plain fun.
It all starts with a simple idea. We know that the
universe is expanding. We also know that if we let
a gas in a bottle expand, it cools. Simple thermodynamics.
Put the two ideas together, turn time around, and
we're led to the conclusion that the universe used
to be dense and hot. Both a simple idea and a predictive
one (the best kind of theory) because if the universe
used to be hot, it used to radiate hot photons.
Indeed, in 1965 those photons were measured.
But
it was the next idea that opened a real can of worms:
if the universe radiated photons when it was young,
and we can measure them now, we should be able to
infer the fundamental characteristics of the universe
by making a measurement of the spatial distribution
of these photons today. It didn't take long for
the idea to be generated, but it's taken 35 years
for us to develop the techniques and technology
to make the measurement.
Now
to understand TopHat, you need to put yourself in
the shoes of some of people who came up with the
idea of TopHat in the early 1990s. That would be
Steve Meyer, Ed Cheng, Matt Kowitt, Dave Cottingham,
and Dale Fixsen. At the time, they were running
a successful campaign involving a telescope called
MSAM. The details of the experiment are not important
but the critical notion is that these were very
scientifically conservative people and these were
people who understood that they were trying to make
a very difficult measurement. This had an interesting
consequence with the MSAM experiment. You see, during
the three balloon flights of the telescope, the
MSAM team was widely criticized for using an ultra-conservative
observing strategy. The cosmology community didn't
want conservatism, they wanted someone to make an
"exciting" measurement that pushed the telescope
to its limits. What Steve, Ed, and the others understood,
however, was that the *only* way to make a successful
CMB measurement was to play it safe. And this strategy
has withstood the test of time.
In
fact, we wrote an interesting and significant paper
in 1998 based on the MSAM data - three years after
its last flight! So here were these guys thinking
about what to do after MSAM. It was already obvious
at the time that what was required was an experiment
that covered a large fraction of the sky with very
high sensitivity. It was also clear that the experiment
had to be designed with the idea that the possibility
of systematic errors (environmental contamination,
foreground source contamination, etc.) had to be
mitigated at all times. After all, these were the
kinds of errors that had been the downfall of most
other CMB telescope experiments. In other words,
what they wanted to design was a conservative experiment.
Enter TopHat.
On
it's face, TopHat does not come across as very conservative.
Number one, it's flown from a balloon and thereby
absorbs all the associated risks of bad launches,
bursting balloons, and weather related delays. Number
two, it flies from the top of the balloon adding
yet another complication. And number three, it flies
in Antarctica - demanding an experiment that can
function properly and reliably for at least seven
days at float altitudes. But while a pedestrian
might shy away from these ideas, in fact, they have
all been done before and the benefits of each to
the quality of the measurement far outweighs the
risks and vastly *increases* the probability of
success. Flying on a balloon puts us above the atmosphere
- a dubiously unpredictable and uncontrollable contaminate
of ground-based instruments. Flying on top of the
balloon gives us a wide and unobstructed view of
the sky - vastly reducing the possibility that our
signal is coming from the balloon itself. And doing
this from Antarctica gives us days of integration
time and, coupled with our observing scheme, allows
us to make the same measurement of the sky each
day of our flight.
How many CMB experiments to-date have had these
leisures? None. Until now. So, in case it hasn't
gotten across yet, I am excited about TopHat. If
it works only half as well as our predictions, we
will still be able to hand the world something significant.
This is something worth spending the holiday season
in Antarctica for. This is something worth being
excited about.
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Thursday
- December 22, 2000 - the first full day of Summer.
See how the ice is breaking up!
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Wednesday
- December 20, 2000
By G. Wilson
The
more I hear about the weather in Chicago, the more
guilty I feel about being away in Antarctica. Reports
include bone-chilling temperatures combined with
lots and lots of snow. Here we continue to have
temperatures hovering right above freezing and at
least part of every day with blue skies and pleasant
views of the surrounding mountains. Don't get me
wrong though. Warm temperatures aren't all they're
cracked up to be. Today I noticed that we have melted
our way nearly down to the ice floor below and the
path between our lab and the outhouse has turned
to slush. I would describe further features of Antarctic
life in this heat wave but I would be forced to
violate my promises about potty humor. That is too
slippery a slope to play near.
We
are nearly finished putting the TopHat subsystems
back together after our marathon disassembly, fix,
and integration. This has been a busy couple of
days. Below I'll give you a taste of some of the
changes we've made and what results we've seen in
our testing today. Overall I should say that we
are extremely encouraged by what's happened.
The
radiometer was warmed up and opened for two operations:
a set of capacitors were placed on our signal lines
to dampen the detectors' microphonic responses and
a cap was installed to cover our input horn. The
cap on the input horn will allow us to work on the
system sensitivity in conditions similar to those
we will encounter in flight. Frankly, doing this
makes the system ultra-sensitive - allowing us to
sniff out noise sources and eliminate them. Both
operations were completed in a day and the dewar
was re-closed and pumped out the same day it was
opened. The following day we cooled it down and
it is now running with nominal boiloffs and temperatures.
The telescope was also disassembled for some small
modifications. RF filters were installed on our
motor amplifier, the coupling between the bearing
and our top platform was improved by inserting some
soft o-ring cushions, the dewar thermal blankets
were reinforced and improved, and the cabling was
re-routed and tied down in flight configuration.
On
a different front, we met with the NSBF folks yesterday
morning to go over our launch day operations and
requirements. The meeting was very productive (despite
my all too apparent lack of sleep from dewar operations
the night before). We passed out our schedule of
what we expect to happen on launch day and went
through it item by item. Amazingly enough, there
were no major surprises as can happen when two nearly
independent groups make plans which require each
other. The most startling thing that was said was
that we will do our compatibility tests and if the
weather is good, we'll then head out to the launch
pad and go for a flight. This is in stark contrast
to the way things work in Palestine where the launch
opportunities only coincide with dawn and dusk lulls
in the wind.
As far as launch day goes, the plan goes as follows.
First they will pick up the bottom gondola and drag
it out to the launch pad. They will then return
and pick up the top package. Steve and I rode on
a balloon-laden sled yesterday to test if the vibration
from the tractor would rattle the dewar to pieces.
It turns out to be a pretty cushy ride (a bit smoother
than my Jeep) so it looks like we can avoid the
headache of installing the dewar on the launch pad.
Once the telescope reaches the pad, we do some tests
of the telemetry and commanding and then give them
the go for tow balloon inflation; the tow balloon
goes up, the main balloon gets inflated, the tow
balloon is released, we orient the package in the
launch-direction, and then they pull the spool.
I must remember to ask if they will provide anticipation-induced
air-sickness bags for the launch. I'm feeling queasy
just writing about this stuff!
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Tuesday,
December 19, 2000: The upper atmosphere winds
are beautiful. Any flight with winds like this would
make an almost perfect circle around the South Pole.
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Sunday
- December 17, 2000
By G. Wilson
It
is said that winter is the time of year that steels
our bodies and minds to the hardships of life. I've
always liked a good winter. I like it snowy and
bitterly cold for at least a few weeks of the year.
I like that it gets dark early and that the snow
on the ground and in the trees muffles the sounds
of the city. I like that people help each other
out of snow drifts and generally acknowledge that
we might as well be neighborly because the difficulty
of winter is mostly unavoidable. So I was thinking
about winter in Chicago today (which I am currently
missing) and it led me to ask - am I experiencing
winter here in Antarctica ... or is this really
summer like they tell me?
Of course we've got plenty of snow, and there are
certainly moments when the cold reminds you where
you are, but on the other hand there is no escaping
the 24 hours of invigorating sunlight and the weather
is not nearly as oppressive as it might be. Despite
these summer features, however, McMurdo (and to
a larger extent the crowd at Willy Field), is a
community of people who are bonded by the dangers
of the weather and its unpredictability. The winter
spirit is alive and well here and it will make all
the difference in being able to bear being away
from our families next week.
TopHat spun atop the Ross Ice Shelf with tremendous
majesty yesterday. At approximately 1:00 in the
morning we brought the fully assembled TopHat to
our remote testing sight and let it run for 15 hours
as the sun rose and circled the package. It was
really a sight to see. During that time we acquired
the data needed to make a calibration of our sun
sensors and our glint sensors. Jeff is working full
time at analyzing that data now. As expected we
found some small bugs in the setup (we need to lower
the suny shade a bit) but they are minor and we
are on to fixing them already.
Once the package came home, we met and decided that
we are ready to do our final tune-up and assembly
of the flight telescope. The euphoria of having
the package fully assembled was short lived as we
began disassembly late yesterday and returned TopHat
to its component subsystems. We are planning two
to three days of subsystem configuration followed
by the final integration. For this next round of
tests, the dewar will be sporting an eye patch at
4.2K and new microphonics shorting capacitors between
gate and return of the six low temperature FETs.
These have been installed and the dewar is back
on the pump in preparation for tomorrow's cooldown.
Yesterday
marked the arrival of Hans Ulrik - one of our Danish
collaborators - to the lab. Hans Ulrik will be staying
through the flight and we are excited to have him
around to help with real time flight analysis software.
Unfortunately, his arrival coincides with Dale's
departure. We will certainly be missing Dale both
during the lead-up to the flight and then again
during the flight. Dale has a way of thinking about
things that is unique to the group. He also thinks
fast on his feet and is great to have around in
a pinch. He also has an uncanny ability to wear
the same cloths 35 days in a row while maintaining
body odor levels lower than mine reach on a sunny
day. Yes, his talents are multifaceted.For
the next few weeks we'll have to learn to take advantage
of those talents that are transferrable via email.
In case anyone is worried about us working too hard
and becoming dull, last night the TopHat crew (minus
our tireless leader but plus Dale!) took the evening
off to celebrate Mardi Gras in town. Why does McMurdo
plan a Mardi Gras celebration in December? See paragraph
two above. I've got to say, it's quite an event
when this town throws a party. The celebratory energy
that is expended is large and even though there
is the unavoidable idiot factor, the town bar was
a fine place to spend a relaxing and entertaining
evening ... Winter is alive and well in Antarctica.
Don't let them tell you otherwise.
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Thursday
- December 14, 2000
By G. Wilson
Christmas
is 10 days away and all I want at the moment is
a shower and a meal that has more starch than protein.
But what can I say? If I've learned anything from
incessant cinema and sports watching it's that you
don't mess with a streak ... and a streak is just
what we're on. Fortunately, that doesn't mean we
have to wear garters (with the rose facing forward).
It means we've got to keep working and making the
great progress that has characterized the last two
days.
TopHat continues to come together. Top system integration
is nearly complete now that the sun shield has been
added to the fray. Last night we fired up the glint
and sun sensors and saw that they are running nominally.
Tonight, starting at midnight, we will have a glint
and sun sensor calibration run. This involves bringing
the top package to the top of a berm (not the one
with the controversial third forker) about 200 feet
from the lab tent.
The package will then run for 12 hours so that we
can calibrate the sun and glint sensors over the
entire range of angles we will view the sun during
the flight. A large fraction of today was spent
working with the dewar and the telescope. The overall
system noise when we are stationary is simply fantastic
... ie, it is consistent with what we would expect
from calculations. Tests from last night have shown
that we likely have some pickup from AM modulation
of one of the dewar resonances. A fix has been envisioned
and DC will do a bolometer calculation tomorrow
to confirm that it is the right thing to do. In
any event, we have been plugging away mercilessly
and we are confident that we will beat down the
rotation-induced noise.
Tomorrow we are scheduled to have prime rib once
again for lunch. Okay, this is probably a good sign
as far as the streak goes, but the fact is that
I've been waking up in the middle of the night yearning
to graze in a warm pasture. I remember days of yore
when Dale would eat steak after steak in Palestine
... for months on end. I would sit and stare in
wonder.
Now here I am in Antarctica and day after day and
night after night I eat cow - three meals a day
(okay, milk isn't exactly roast tenderloin but you
know what I mean). This isn't nearly as disturbing
until you remember that this is the *only* continent
on the earth where there are no cows! In fact, I
was privy to learn this morning that I have yet
to eat something here that has not been on this
continent for at least 12 months. If that's the
case, why aren't we eating Roquefort based dishes
or Antarctic kimchi? Such are the things I ponder
in the daylight of Antarctica in the middle of the
night. This place is wonderful ... but very odd.
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Wednesday
- December 13, 2000
By G. Wilson
Noise,
noise, noise. That's all that comes from the speakers
here. Those graduate students have loaded our computers
up with loud, inexplicable noise that plays incessantly
throughout the day. I keep asking them to fix it.
They just look at me befuddled. The best they can
do is to stop the DJ from spinning disks. That certainly
helps but as soon as they're going again my brain
starts to throb. I just can't stand that noise much
longer. We really must do something about it. We've
tried putting the source outside on the snow and
it didn't help much. I am currently planning my
next move to get some peace and quiet around here.
The
weather, on the other hand, continues to be beautiful
here. Today must have been in the 40's - allowing
me to walk to the galley in short sleeves at one
point. I'm feeling sorry for those poor souls in
Chicago who are dealing with -30 degree wind chill
and a foot and a half of snow ... especially since
I nabbed all the cold weather clothing on my way
out the door.
Dave
continues to think deep thoughts about the flight
software. He has been tasked with making a final
review and searching out any small bugs that might
lie within. He is finding the task quite challenging
and we all should thank him for this after the flight.
This kind of detective work is a bit numbing and
is quite tedious ... Fortunately, the cook provides
a steady stream of sugar in her time-release deserts.
This seems to be plenty to keep Dave going throughout
the evening.
As I understand it, the balloon group next door
is holding at launch minus two days while they try
to repair a software problem in their system. The
pressure is on now. The Pathfinder (a balloon that
they use to measure the wind speed and direction
at "float" altitudes) is showing that the high altitude
winds have indeed set up in a vortex around the
continent just as the ground based sensors previously
hinted.
To
see the current position of the Pathfinder, check
out http://192.149.107.13/ice0001.htm.
To check out the ACLU homepage, go to
http://www.aclu.org/
Best
to all -
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Tuesday
- December 12, 2000
By G. Wilson
Yet
another day passes for TopHat in Antarctica. Will
some find this a depressing thought? I don't think
so. Each day we are one day closer to our launch
date. Each day we encounter new challenges, overcome
old obstacles, and reach and explore our own limitations
as both scientists and people. Some of these days
are difficult. Some of these days bring great surprises.
And some of these days leave us wondering why we
ever came here in the first place.
In
the end, however, these days before launch carry
with them the ever-growing anticipation of the flight,
that each of us has felt, for better or for worse,
with them since joining the project. Is the first
kiss ever as interesting as the 10 minutes before?
Rarely ... and in this case I'm betting that it's
these days that I will be remembering 10 years from
now. Not in detail but as a collection of dinner
conversations, tough experimental problems, and
writing corny letters home. I'm really enjoying
this time.
That being said, I want to announce that dewar B
is cold once again! In past notes I have glossed
over the idea that we had warmed up the dewar and
gone in to fix a wiring problem. Well, as most know,
this dewar is made of eggshells. Once closed and
working, it's a pretty reliable companion. Inside,
my hands feel like 20 pound balls on then end of
tree trunks. This dewar is damn hard to work on.
Thankfully, due much to the outstanding diligence
of Crawford, who slaved away opening and closing
the thing for four days straight (two of those while
I was off playing at snow school) - disdaining breaks
(and showers), we now have a functioning cryostat
again.
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Monday
- December 11, 2000
By G. Wilson
Another
busy day for the TopHat crew. The dewar is coming
back together quickly and so far it's looking pretty
good. I think we've made some fundamental improvements
in both the signal wiring stability and the optical
alignment. With luck, tomorrow will come the big
test where we cool it all down and see if we re-assembled
it properly.
Today
we met with Victor (the NSBF crew chief) and had
a discussion about the schedule of events that will
occur on the day of the launch. Somehow, despite
the fact that I've travelled thousands of miles
to Antarctica after working for years on this project,
this was the event that made it all seem very real.
What's more, Victor is as gracious and accommodating
as we could possibly desire ... clearly not a true
government worker. We pounded out a launch day schedule
that looks quite reasonable on its face. I will
send this out to the balloon mailing list as soon
as I get it typed up (typing happens only when I
can trick Tom into doing some dewar task that I
should be doing ... I've sold him the same dead
one-eyed cat four times now and there's no telling
if he'll go for it again).
After
dinner tonight, Tom, Jeff, and I went outside and
snapped some pictures while displaying some Peets
coffee. Hopefully I'll get them by the government
censors and we can sneak them onto our web site.
You see, not only does Peets coffee fuel the TopHat
machine, the nice folks at the Peets in Chicago
(1000 W. North Ave near the Whole Foods) actually
gave us some free coffee and a few thermal mugs
for our trip. I'm reminded each morning how much
we owe these people. Please tip well if you happen
to be in the neighborhood!
Finally,
I've promised to not pick on James this update.
Jim, on the other hand, has no such immunity. Poor
Jim. As I type he is taking a nuclear physics exam
in the sleeping jamesway. I just went over to find
a spare sleeping bag and found him sprawled out
on the floor consulting a magic 8 ball ... oh well,
the world needs ditch diggers too.
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Sunday
- December 10, 2000
By G. Wilson
Sorry
about the lack of updates lately. I have been subjected
to snow school for the past few days and I forgot
to ask someone to take up the typing slack in the
meantime. From the progress made during my absence,
it's clear that no one was able to take time to
write anyway.
TopHat
preparations continue. We have been working on re-configuring
the cryostat wiring to eliminate a spurious noise
source. This has taken a bit more time than originally
expected but we hope to be back up and running with
our cold detectors shortly. On the telescope front
there was a major discovery and quasi-cure of a
clocking anomaly in one of our counter circuits.
Jeff, Steve, Dale, Renee, and Cottingham all looked
into it ... it was a nasty little bugger ... and
it's now been beaten down into an ignorable phase
slip that happens every few minutes or so.
While
I was away at snow school the new airport went in
next to the lab. This is an amazing transition.
Overnight, a crew at McMurdo effectively transplanted
an entire airport about 15 miles - from the decaying
sea ice on the North West side of McMurdo to the
permanent Ross Ice Shelf on the South East side
of town. Willy Field was completely unrecognizable
when I returned. There are several new buildings,
three C-130 transport planes parked in our backyard,
and the entire area has been plowed as flat as the
top of my head. It is a very impressive piece of
engineering and planning.
Oh, and a warning to those who are imminently arriving.
Bring your cold medicine. I don't think that anyone
has avoided the McMurdo crud yet. Even my mighty
immune system was overwhelmed within a few days
of arriving. Lately it has been James and Gwynne
that have been struck down (insert speculation here
... and then forget about it ...). If you are soon
to arrive at McMurdo, I would recommend taking vitamin
C supplements before you get here and make sure
that you arrive rested and ready to hold your breath
whenever talking to anyone else.
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Wednesday
- December 6, 2000
By G. Wilson
Folks
-
Progress continues. We continue to attack our weak
points meticulously and systematically ... well,
okay, we're at least hacking away at the problems
that jump out at us. Much has happened during the
last two days.
We've
uncovered a potential bug in the main radiometer's
wiring. We've warmed up and are currently in the
process of mechanically tieing down the bolometer
wires better. This is an extended process since
we have had to open the dewar down to the cold plate.
As always, however, many improvements have been
made to the baseline system that wouldn't have been
made otherwise. Is this a blessing in disguise?
James
and Jim are staking claim as our amplifier gurus.
These guys knuckle down and do the really hard and
fragile soldering for amazingly extended periods
of time. I'm concerned for both of them and their
vision. This work involves a lot of staring and
sharp focusing on small objects. Fortunately, our
post-dinner incessant ABBA playing has encouraged
Jim to take a break and go for a snowmobile ride.
James, on the other hand, is swaying in his seat
to "I Have a Dream" as I write. God bless Sweden.
We
are told that the airport will soon be moved to
Willy Field. We are all looking forward to this
as it means there will be a half-hourly shuttle
service between the lab and McMurdo. This will,
hopefully, encourage us all to take more evenings
in McMurdo and find a bit more time to relax ...
or at least get a shower ...
I
did forget to mention in my last update that Dave
and Bob have successfully orchestrated an observation
of TDRSS data via an actual TDRSS satellite. Congratulations!
This is a noteworthy milestone since it demonstrates
that we have the capability of getting our in-flight
data back from the telescope in real time.
Finally,
a slightly sad note. After a day of working on getting
dewar Y cold, which it did (!), Dale and Eun discovered
a small helium leak in the top of the main helium
dewar. This is a particularly ugly guy since it
seems to leak liquid helium much more efficiently
than the gas. It wasn't a problem until they filled
the helium tank entirely and the dewar went soft.
This is a small setback but at least it's only the
backup dewar. Our plan is to get on trying to locate
and fix this leak tomorrow.
Cheers -
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Monday
- December 4, 2000
Raytheon Polar Services Company Update
By Bill E. Haals, McMurdo Station Manager of Operations
Good
Morning McMurdo & Scott Base,
It
is that time of the year for the annual move of
runway systems from the sea ice to the ice shelf.
For those of us that have been around this marks
one of the biggest milestones in the season, more
or less the half way point and also the time we
change the way we have been doing business.
Travel
to Williams Field is on the snow road. The snow
road is just that, a snow cover over the ice shelf
approximately 25' thick. The ice underneath that
25' of snow is a couple of hundred feet thick floating
on top of 1800' of water. That is your road surface
lesson for the morning. Next lesson is how we deal
with this unique road, especially this season with
all the new snow that keeps falling on the compacted
sections.
The
snow road is made up of 4 lanes outbound to Williams
Field and the same lanes for return. 3 of which
are for wheeled vehicle traffic and one for tracks
and chevron tire Deltas. One wheeled vehicle lane
at a time is open for travel. The road itself is
under a continual compaction by heavy machinery
pulling a variety of compaction equipment. The road
will fall apart if it is not respected and certain
rules must be adhered to.
As
most of you know the new fleet of trucks are not
equipped with tires that are made for this kind
of environment. Even the ones that do have the flotation
tires are not traversing the snow road as they should.
Why? This is a very heavy snow season and the compaction
of this road just keeps getting covered up with
new snow. We need to cut back the amount of vehicle
traffic while still keeping the system operational
out at Williams Field.
Come
Saturday, the day the Ice Runway is re-located to
Williams Field only flotation tire or tracked vehicles
are allowed to Williams Field. The day of the move
there are some allowances to get needed vehicles
to the skiway for the construction of the airfield
and those to be stationed out there for the airfield
but after that we have to limit the amount of traffic
and rely on the Shuttle System and whatever else
we come up with. This includes aircraft parts re-supply
and AGE resupply, you will need to rely upon transportation
using flotation tires or tracks. Some of you are
going to ask how you can get your jobs done by not
being able to drive back and forth all the time
but you can be innovative. For aircraft & AGE parts
those can be brought from town to the transition,
placed on a shuttle or a flotation tired vehicle
and taken out to the airfield. The same goes with
a lot of other needs. We do have some rims for flotation
tires and lift kits on the way that we will be placing
on certain vehicles but until that time you are
going to have to rely on other means.
For
those of you using the snow roads there are a few
rules. The road is being compacted as best as possible
but between the flag lines it is not compacted in
any way shape or form. If you cross between the
flags you will get stuck driving a truck no matter
what kind of tires you have and then you get to
meet one of the operators with heavy equipment -
that just might bury you deeper and keep going.
The faster you drive on the snow roads the more
your vehicle will tear it up and the faster it will
deteriorate. Go slow. Also scrape (I didn't say
"beat") the mud and dirt out of the wheel wells
before driving onto the snow, a barrel with wooden
handles will be available for that use just before
the Scott Base transition. Dirt hastens the melt
of the transition.
The
snow road is your means of accessing Williams Field
and it is up to you to keep it in the best shape
as possible. Just think what is going to happen
to it once this snow starts to heat up and melt...
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Tuesday,
December 4, 2000
By G. Wilson
Another
day closer to launch for TopHat. During today's
meeting with Steve Peterzen from the NSBF we were
shown 3 mbar and 4 mbar surface wind plots for the
continent. They are beautiful! The center of the
vortex is right over the south pole and the wind
lines were all nicely tangential to lines of constant
latitude. In fact, Steve says he hasn't seen it
set up this early and this nicely before. More to
the point, he said, "Well, if I were flying an experiment
this year, I'd want it to be ready for flight sooner
rather than later." That officially makes two of
us. NSBF will be putting up a sounding balloon at
the end of this week to see if the upper atmosphere
winds have set up as well. After all the travel
problems it caused, the weather may be starting
to smile on us after all!
A lot of dewar work went on today. We have explored
the dewar hold time as a function of the dewar tilt
and now have some new knowledge on the flow dynamics.
This is a nice step forward. As Dale's note today
said, we have also put LN2 into dewar Y (the backup
dewar) and we plan on cooling it the remainder of
the way tomorrow. Finally, noise testing continued
on dewar B and we determined that it has more microphonic
(vibrational) sensitivity than we would like. We'll
most likely warm it up overnight and attempt to
search out that bug tomorrow.
I
also saw Tom and Jeff milling about the telescope
and I'm not sure James removed his head from inside
one of the amplifiers all day. As promised, Tom
has found the root of the problem with the GRT readout
and has fixed it. As I understand it, a significant
amount of cable fixing and patching also got done
... all small jobs that tend to stack up. Kudo's
to those guys who hammered through them!
Now
to correct a mistake from my note yesterday. When
I first arrived to McMurdo it was a condition 3
day ... not a condition 1 day (which would have
been quite difficult to land in!). Thanks so much
to those thoughtful souls who informed me of my
slip-up. In fact, I liked the bevy of responses
so much that I think I'll slip in at least one lie
into each update I pen. I'll leave it as an exercise
to the reader to sniff it out.
By
the way, it was steak for dinner again tonight.
I personally saw Cottingham and Crawford eat nothing
but salad (no dressing) and water. Tom was heard
to say that his days of multi-big mac eating are
behind him ... so to speak.
Wishes
of warmth to all -
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Sunday,
December 3, 2000
By G. Wilson
Greetings
from the Ice.
We've
had a slight swap of responsibilities. Ed has headed
back to warmer climates and has handed off the torch
of update writing to yours truly. I pledge to reduce
the potty references ... but only after expressing
my deep regret for not bringing potpourri as Eun
had requested. This was a true mistake.
Last
night Dave, Alex, and I came into town to find a
beautiful condition 1 day with low winds and the
temperature hovering just above freezing. While
making it quite comfortable for sightseeing and
acclimation around McMurdo, the warm temperatures
had the unpleasant effect of turning McMurdo into
a volcanic swamp. Unfrozen, McMurdo is actually
quite yucky. The big trucks (with BIG wheels for
getting around in the snow) tend to make large ruts
in the soft road in the absence of ice. After the
thaw, these ruts are filled with black mucky water
- making us all glad we were sporting our huge ECW
boots which we had all been grumbling about carrying
around just a day before.
Ed must have worked hard while in town because he
never mentioned the various activities available
to McMurdo's citizens. From my count, McMurdo has
two bars (one smoking and one non-smoking), three
gyms, a coffee bar (where they also serve wine),
and a bowling alley. Rumor has it that all the alcohol
in McMurdo mysteriously disappears when the ice
breakers and their rambunctious crews come in ...
go figure. In any case, as I understand it our younger
folks have not had trouble keeping busy while the
old farts spend their night in the lab. I'm still
working on figuring out which side of the fence
I sit on ...
As
far as progress goes, dare I say that things are
going quite well. The dewar remains cold and Dale
and I have been working on fixing a bug in the hold
time software. We think we have a handle on it.
As far as the remainder of the package goes we have
decided to spend some time servicing the top payload.
The hope is that over the next day or so we can
get the amplifiers buttoned up for more noise tests,
the GRT readout reading out again, and the package
buttoned up in a flight-like manner for more noise
testing.
Finally,
I must report that McMurdo, or maybe it's the snow,
or the sun, or something ... whatever it is, something
has had an effect on the people of TopHat. It all
started with a hot nickel. Now I am hearing rumors
of indecent snow showers under blue skies and Korean
moons flashing in the night. Tom has a beard, Jeff
a mustache, and James got a haircut ... as far as
I know, Alex's hair is still brown and covering
the majority of his head.
I
think I'll be sleeping with one eye open tonight.
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