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Adventures in Antarctica by Tom Barfield Saturday, December 4, 1999 Imagine looking out on the ocean when it is a little choppy. From horizon to horizon the view is of a flat plain with a lightly textured surface. That is what the Antarctic plateau looks like, except it is frozen and still. When I came here, we were told Antarctica is the highest, driest, windiest, coldest continent. After four weeks working in actual temperatures of -35 to -45 deg C and wind chills up to -100, I believe it. The ice has texture. Here, the mounds and waves are called "sastrugi" which is a Russian word for wave (so I'm told). Sastrugi are sculpted by the wind and are infinitely variable in their detail, but the same as far as you can see. This phenomenon is an excellent example of fractal geometry, the patterns in the snow look the same from an airplane flying over it (5000 feet) as it does standing on it.
South Pole Acclimation
I have described McMurdo Station as a frontier boomtown. The South Pole is a mountain mining camp that runs 24 hours a day. I can only describe life at the Pole as "Manic." Two hundred boisterous workers crammed into an encampment designed for forty. As an aside, the recreational ads at the South Pole proclaim "Ski South Pole - 2 inches of powder, 2 miles of base.
Home Sweet Home
The food at the Pole is not as good as at McMurdo. Part of the reason is that a mess hall designed for forty customers is feeding two hundred. The place is very crowded and you really have to know how to get along. After several meals, the food develops a sameness and you tend not to eat so much. In the cold, you burn a huge number of calories maintaining your core temperature, and from time to time, you have to force yourself to eat and drink. Once we got to the AGOs, I was drinking 3 to 5 quarts of water a day (and exhaling most of it).
Flight to AGO
Before the plane could leave, we had to make contact with either the Pole or McMurdo. While the pilot and co-pilot helped Joe unload the gear, Kevin and I put up the antenna and called in. We use an Army high frequency 20-watt tactical radio, and can talk 1000 miles on it. We made contact on the first try. As soon as the pilot got our thumbs-up that we had radio communications, he took off and left us in the middle of a frozen desert with the nearest help 290 miles away (the Pole). It's a lonely feeling. We had not even opened the door to the AGO. The temperature was -40 C and the wind was blowing 20 knots. Under those conditions, you cannot expose any bare skin -- it will freeze. With establishing radio contact as the first priority, second and third priorities are getting warm shelter, and making water. Our primary shelter is the AGO, itself. The AGO is an insulated fiberglass box 8' x 8' x 16'. The heat source inside is a thermo-electric generator, or TEG. AGO-2 had mysteriously shut down several months ago and we would not find out why until after we entered the shelter. AGO reliability has been a problem in the past. There are several failure modes in the thermo-electric generator, and the two most common are blockage of the exhaust by ice and plugging of the air intake by snow. There is a thermocouple that measures the inside temperature of the AGO, and when it reaches -20 C, a valve closes and shuts off the propane to the generator. This circuit uses 10 C-cell alkaline dry cells. Last year the batteries were bad, but this was discovered only after servicing all the stations. We fully expected all the propane (1000 gallons) had been pumped into the station. Joe and I opened the AGO door and expected to be overpowered by the odor of propane, but the air was clean. The shut-off valve had worked! The interior air was clear of the stink of ethyl mercaptate, the oderant put in propane. At AGO-2, the batteries worked and we had no problem. An ice plug in the air intake caused the shutdown. By the way, in the cold of winter, the propane stays a liquid or slush if it leaks into the AGO, but when the sun comes up the shelter warms up enough that the propane vaporizes and dissipates through cracks and crevices in the shelter. What is left is the stink of the oderant. We use a car battery to start the station. We bypass the control circuits, switch the propane valve to manual and open it, switch the propane source to an auxiliary 100 gallon tank located just outside the shelter, and fire up the thermo-electric generator with the car battery. AGO-2's generator fired on the first try. After an hour, the temperature in the AGO was a balmy 0 C. By the end of the day, our English reading thermometer, placed near the ceiling, read 60 deg F. It stayed at that temperature for the rest of our two-week stay. We initially had a five-gallon propane tank inside the shelter for cooking. Needless to say, having that much propane inside an enclosure is not good for safety, so we got another 100-gallon cylinder stashed in our cache last year and strapped it to the AGO leg opposite our auxiliary cylinder. It took us about an hour in the cold to lug the cylinder 500 yards from the cache, secure it, and run a copper line from the stove to the cylinder and make all the connections. At AGO-2, we will be able to cook for the next three years before refueling.
Survival Means Being Systematic
Kevin went to put up his tent and organized our cargo line. In the cargo line, we keep the stuff we need during our stay but can't put in the shelter. All our food goes in the cargo line, our backboard, the window covers, the ladder for the roof, extra clothing bags, and things like that. Our survival bags plus a gallon of Coleman fuel go in a location away from any tent or the AGO. That way if something burns down or is destroyed in a windstorm, the survival equipment is not lost too. Our cache is located a hefty walk away and contains food, repair parts, aviation fuel for the twin otters, gasoline for the ski-doos, the runway groomer, and two ski-doos. All this stuff insures that even in a disaster, we will be able to hold on for several days or a week until help arrives. Our next priority (Ahem) was to put up the potty tent. Much of Antarctica is designated by treaty as a "non-accumulation zone" which means you leave no trace of your visit. That includes removing all human waste. AGO sites, however, are accumulation zones, so we are allowed to dig latrine holes. We have a nice little wooden box with a warm styrofoam seat to cover the hole. Once the hole is dug and the seat in place, we put a Scott tent up over it. You always try to get the box on one side of the tent, just in case your buddies have a lot of throughput and fill up the hole. There is space to dig another one without moving the tent. We got the potty tent up in jig time and ran an operational test within an hour. The first meal in an AGO is always dehydrated, which is called "dehy." The reason is simple: you are exhausted and don't want to cook! Kevin, Joe and I were beat by the end of that first day, and all we did was boil some water, eat a dehy and drink a couple of mugs of tea or cocoa. I was so glad to crawl into my sleeping bag that night. Our day had started at 5 am at the Pole and ended about 11pm at AGO-2. In between had been a nearly full day of intensely aerobic activity. Over the next five days, Joe and I accomplished the station modification that was our mission. We installed solar panels on all four sides of the AGO. The solar panels gave us energy independence for our electrical needs and give the AGO backup power that can reactivate the station if the TEG fails during the winter. In addition, we modified the electronics in several experiments, replaced all the AGO control and data collection system, re-cabled the shelter, and modified the TEG. Kevin made a 10,000 ft long by 150 ft wide skiway with a 2000 ft long side ramp for the LC-130 to land on. Kevin's main tool for this job is a device called a groomer. The groomer is a sled that has six heavy steel "teeth" that break up drifts and sastrugi and a rake that smooths the lumps out. The groomer is pulled by a snowmobile. Making a skiway takes 40 to 60 hours of continuous work, so preparing for our extraction begins many days in advance. If a storm comes up and obliterates our skiway, we start over. That's why we take a lot of food and fuel with us. After Joe and I finished the upgrade, we verified all the science experiments. We made sure they were working properly, calibrated a couple of them, collected data for 24 hours, stored the data for later study by the investigators, and verified that our storage computers were performing properly.
Departure
We had called for an extraction on November 16, but our weather was bad and the flight was cancelled. November 17 "dawned" bright and sunny (and -40) and Air Ops said they would send a plane for us, but not until 8pm. About 5pm, everybody got a chance to use the potty tent one last time and we packed the Scott tent up and covered the hole. We also pulled in the metal staging that formed our front porch and prepared the AGO for departure. The LC-130 arrived on time and dropped us two new pallets of propane and proceeded to the retro line to load cargo. Joe and I connected all the pipes for the propane (we call it manifolding), which takes about 45 minutes. This operation requires significant manual dexterity and we wear lightweight blue gloves under our mittens. We can pull our hands out to start a nut and then shove our hands back in our mittens to do the wrench turning. The blue gloves aren't warm, but they do keep your fingers from sticking to the metal. Kevin helped the latinizer on the aircraft load the cargo. The plane was on the ground about 1-1/2 hours and the pilots never shut the engines down. We were airborne by 9:30pm and we arrived back at the Pole at 1:30am on November 18th. The housing folks had dropped the ball and we had no place to sleep. Joe and Kevin hot bunked with two folks who were on night shift in the communications room and I slept in the infirmary. By 1pm on the 18th housing had found rooms for us. But, we planned to leave for AGO-1 the next day -- Nov 19th! Thus, we got only one night's rest between trips.
Problems at AGO-1
When Joe and I got to AGO-1, there was an ominous iceberg on top of the AGO. This is one of the failure modes I told you about: a blockage of the TEG exhaust. Also, one of our radios failed and we had trouble making communications. As the twin otter idled, we desperately tried to raise McMurdo, but could not. Finally, we pulled out our trusty back-up, an Iridium satellite telephone, and called them. We didn't know whether Mac Ops would let us check in by telephone, but they did. The temperature was -40 C with a 35 knot wind. The wind chill was somewhere around -90 C. If we worked hard, we might be able to stay out for several hours before we went completely numb, so we had to get heat and water quickly. When we opened the AGO door, the stink of propane was almost overpowering. The shut-off batteries had failed and all 1000 gallons of propane had passed through the AGO on its way to open atmosphere. We got out the stage and set it up, then put a ladder on the stage to get to the roof. The iceberg weighed about 200 pounds and completely blocked the exhaust. In addition, there was an inch-thick hockey puck of ice in the intake. Joe and I chipped the iceberg off and cleared the intake, but we were concerned that ice had formed all the way down the stack. We could not start the TEG. Nothing. Nada. Zilch. We cut the insulation off the exhaust stack, loosened it and verified that it was free of obstruction. We had propane, but the TEG was dead. The temperature in the shelter was -30 C, but mercifully there was no wind. On top of that, the cylinder containing cooking propane was almost empty. We dipped some snow and ice out of a drift and made some water. The heat of the stove got the temperature in the shelter up to 0 F -- warm enough to work in our blue gloves. The TEG was full of ice, and we had to get it out before we could begin to heat the station. Normally, an ice-filled TEG requires complete disassembly and warming to get it to work again. Joe and I did not have that option. We needed a short cut. One of the design features of the TEG is a venturi throat that mixes air and propane before it enters a combustion chamber. This venturi also reinforces a draft through the system. The TEG contains six of these venturi-combustion chamber units. We began by assembling a propane torch from our tool kit and using the cooking gas. First we heated up the exhaust manifold by directing the flame down the exhaust pipe coming out the top of the TEG. Next we adjusted the torch for the longest flame we could get and started melting ice out of the ventures closest to the exhaust. After an hour of heating and a lot of water (then ice) on the floor, we got two burner assemblies to draft (meaning there was some kind of path through the TEG). We reassembled the TEG and tried to fire the two burners we thought were clear. We got one of them going. We let our one burner fire for about 45 minutes while we boiled some more water and had something to drink. The heat from our one burner melted enough ice that we could start the other burner. With two going, we had almost enough heat to keep the station warm. Three burners will keep an AGO warm. We shut the TEG down again, and tore it apart to try to melt more ice with the propane torch. Over the next two hours, we got drafting in five of six TEG burner units. Kevin arrived about halfway through this process and we stopped to help unload the twin otter. Shortly after Kevin arrived, we ran out of cooking gas. We took the banana sled out to the cache and dug up one of our 100-gallon cylinders and hauled it back to the shelter. While Kevin strapped the cylinder to the AGO support, Joe and I ran a new copper tube from stove to cylinder and made the connections. While we could cook, we no longer had a way to fire our torch -- we were going to have to use the TEG to clear itself. By 11 pm, we had four burners going (no power out, just heat) and decided that we would call the day a success. We were hanging by a thread, but we had our Iridium phone, we had enough heat, and we could make water. Over the next several days, we took the TEG apart three times to fix broken parts. The one burner we could not start on the first day had a thermal break between it and the back plane and we had to reapply heat sink compound to get its operating temperature within design limits. We also had to replace igniters and thermistors in three other units. Opening the guts of a TEG is a major procedural undertaking and very messy with rock wool insulation. It was just something that had to be done. When we closed the AGO on our departure, that TEG was humming along at 230 dec C and putting out 45 watts at 28 volts -- exactly what the design spec says it should do. Learning curves work. The station upgrade for AGO-1 took two days less than with AGO-2. We had learned where to look for the problems and "goths" and we fixed them as we went.
Upgrade to AGO-1
Our extraction was three days late due to no flying over the Thanksgiving holiday. We were picked up on Monday, November 29th at 8:30pm and were back in McMurdo about 12:45 am, on the 30th. It was good to get back to town, and I was very tired. The team took several days off to sleep. The other team had major problems. AGO-3 took a week longer than expected, due to ski-doo problems that held up ski-way construction. AGO-4 had to be abandoned because two groomers (people) got altitude sickness. Altitude sickness is potentially life threatening, and when it occurs, the whole team is extracted. AGO-4 was abandoned with the camp still set up. We may try again to service the station in January and recover the data disks. We lose all twin otter support on January 1st, so if we are not in by then, we will wait until next December to go in and patch things up. We plan to leave for AGO-5 and AGO-6 between the 9th and 15th of December. Things are still somewhat in flux on the aircraft schedule, so there may be changes. The plan calls for a put-in to a camp called mid-C for acclimatization first. Then we will get put in to the AGOs. I'll let you know how things go. So far, so good. This is very hard work, but also a real adventure. I'll keep in touch. -- Tom Barfield |
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