Images of

ANTARCTICA

Ballooning

Photos © 2002 Seth White

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One of the projects involving the science technician is launching scientific balloons during the winter. This project varies from year to year. Some years there will be no launches, and other years there will be many....depending primarily on funding. This year, there is an ambitious program ongoing entitled Quantitative Understanding of Ozone losses by Bipolar Investigations, or QUOBI. This project is funded by the EU and involves a consortium of primarily European research institutions whose interests lie mainly with ozone loss in the Arctic regions (Arctic ozone loss has been an area of intense research in Europe, for obvious reasons: Northern Europe contains a large number of people who would be...and are...directly affected by ozone loss in the Arctic). For several reasons, the Arctic has not experienced nearly the severe levels of ozone loss that the Antarctic has. This is mainly because the Antarctic is much colder. Low stratospheric temperatures are required to initiate the chemical reactions which destroy ozone. The Antarctic also has a more stable Polar Vortex than the Arctic. The Polar Vortex is a large roughly circular wind pattern which forms over the polar region(s) in winter and effectively isolates the region from inflow of warmer air from elsewhere on the globe. There are various uncertainties and discrepancies between different measurement techniques, and between the measurements and certain aspects of their models. To resolve such issues and improve the capabilities of the climate and chemical models, it is desirable to apply the measurements and modeling to the most well-behaved environment possible. As it turns out, the Antarctic is more suitable than the Arctic for this, for several reasons. First and foremost, the series of steps leading to the ozone hole are much more likely to happen (and in an orderly fashion) here than in the Arctic. The polar vortex here is more stable over the course of a year, and its variation in size and duration is not as great from year to year. It is consistently colder here, and the overall ozone loss is greater (and thus easier to measure!). In short, this is a better place to validate and improve their measurement techniques and models...so they decided to launch a measurement campaign here during 2003. A large part of this project is coordinating balloon launches around the continent...a "match campaign". A total of 9 Antarctic stations were involved in this project. The idea was to launch balloons in sequence from different stations, trying to get as many balloons as possible launched up into a selected "air parcel" as it made its way around the continent in the Polar Vortex. This way, the temperature, pressure, and chemistry of the same bit of air could be sampled at different points of its evolution. This technique has been applied successfully in the Arctic, but this is the first time for the Antarctic. So in addition, much more about the evolution of the Antarctic stratosphere will be learned as well. The longtime PI for the balloon studies at McMurdo is Terry Deshler from U. of Wyoming at Laramie. He came down in February to train Olivia, myself, and Rebecca from Scott Base on the mystical (?) arts of balloon launching. This is Terry overseeing one of our practice launches.

Here's me holding a plastic balloon just after filling, and just before launch....and looking idiotic as usual.
This is Rebecca and Olivia, with a rubber balloon. The thing hanging from the balloon is the "weigh-off". This is just block of metal which provides a weight by which the proper amount of balloon helium fill can be gauged. When the balloon just lifts this weight off the ground, it will have the proper lift to carry the payload up through the atmosphere at the desired rise rate...a few meters per second.
The rubber balloons are easier to launch, however they tend to pop when they get below a certain temperature. They will stretch and expand as they go upwards (they are not a constant volume balloon) and when the temperature gets lower, the rubber gets more brittle and will tear. The plastic balloons, on the other hand, are much larger. They are a constant volume balloon, meaning the plastic (mylar, a few thousandths of an inch thick) does not stretch. We fill it about 1/4 full on the ground and by the time it reaches the stratosphere it is completely full (and has started to become pressurized relative to the outside air). These balloons fly higher but are more difficult to launch. After the end of the balloon is filled with the proper amount of helium, the rest of the balloon must be unpacked and payed out in a line. I'm holding the bubble here while the rest of the crew gently carries the rest of the balloon out, with the payload attached to the other end.
Here, we're just about ready to launch the thing. Phase 2 of the Crary lab is in the background.
And it's off. It doesn't look like much here, but the balloon will be huge when it gets into the high atmosphere and the helium can expand.
Another one of the plastic balloon flying, with Ob Hill.
Here we are again, this time with a rubber balloon. In February, we practiced with both kinds of balloons. However, during the winter we only launched plastic balloons. The plastic balloons are preferrable not only because they fly higher (and thus longer), they have another advantage over rubber balloons. Our payloads during the winter were ozone sondes...instruments which measure the concentration of ozone (pressure, temperature, humidity, etc. were also measured). The rubber material can actually react slightly with ozone, so if the payload is not far enough away from the balloon, the balloon itself can interfere with the measurement! So although rubber balloons are easier to launch (mainly because they're harder to rip and tear), we had enough plastic balloons to last the winter so we used those.
And here goes the rubber balloon.
Winter balloon launches began in June. The primary people involved were Olivia, myself, and Rebecca. However, it is helpful to have 4 or preferrably 5 people to handle the launch of plastic balloons. So we solicited volunteers from around station to help out. A lot of people were interested, and we got permission from the supervisors for them to help during work hours. A win-win situation! But first we had to give them a short primer on how to launch a balloon. So here are Rebecca, Olivia, and Fox Rogers (refrigeration tech) during balloon school.
More thrilling balloon school action! The girls assembled a couple garbage bags as a simulated balloon and the volunteers took turns using the helium gun to fill it a little. Then, they payed out the "balloon" in this room inside Crary and simulated a launch. Usually, the winter balloon launches are handled by the McMurdo science tech. But this year, there were too many of them for me to handle along with the other stuff I have to do. So Olivia was hired as a second science tech. Her primary job was the balloons, and she did a great job. My job here was pretty minimal. I helped out a little bit with some instrumentation and data recording issues, and came down to help out with most of the launches. It turned out to be a pretty good division of labor during the winter with two science techs. The balloons didn't take up 100% of her time, so she could help me out with a few things here and there. Likewise I was a good hired hand for the balloon business.
Prior to the launch season, they had set up caches of helium tanks at various points around town. This was because of the unpredictable wind patterns. Launching a balloon is greatly complicated by winds, so the calmer the better. Since the winds can vary quite a bit from point to point around McMurdo, it was desirable to have helium tanks here and there to provide a choice in launch sites. But as it turns out, we only ever launched from one site: the new wastewater treatment plant. This building was just finished this year, and just in time too! Little did they know that in addition to cleansing thousands and thousands of gallons of McMurdo's sewer sludge each day, it would provide the ideal launch site. The building is at the bottom of a little hill near the sea ice, and is fairly tall. There is a nice flat, open area near the loading bay, and you can easily set up on either side of the corner of the building...depending on the winds. The helium tanks were stored inside the loading bay, and the building's outside lights were nice during the winter. This is a picture of the wastewater plant, taken during one of our winter launches. Here, you can see the helium hose running out from the loading bay to the rightmost corner of the building.
This is a larger view of the launch site. We usually set up on the right side of the building, and used the truck's headlights for some additional light. With the goal of following air parcels around the continent, finalized launch requests were emailed to us from Germany about 12 hours in advance. We had an optimal time window during which to launch, and these were often unusual hours (and waaay too many Sundays). But hey, that's the price of doing science I guess. On the other hand, we were often able to sleep in when we wanted during the winter...no clock-punching is required of the winter-over science technicians!
The helium tanks, inside the loading bay. My job for most launches was the helium tank guy. I would usually arrive a few minutes early (sometimes by bicycle...notice the TRUSTY SCHWINN here), and roll out the helium hoses, and attach the helium gun. I would then go back inside to make sure the hoses were connected to helium bottles with enough helium for the day's launch and check the pressures on a couple other helium bottles in preparation for the next launch. The rest of the bunch would then arrive with the payload and other tools of the trade. Each ozone sonde we launched required some conditioning in advance, to get it "broken in" and stabilized to make accurate ozone measurements. So after doing this, Olivia would arrive with Rebecca and the volunteers...
...and start setting up. One of the first tasks was to lay out a tarp over the ground and unpack the balloon from its box. This is what they're doing in this picture.
Once the balloon was unpacked, the helium fill tube was extended and the helium gun was inserted. I got the signal to open the helium bottle, and the helium gun guy (or girl) would then open the gun slowly. They let just a trickle of gas flow into the tube and balloon at first, to make sure the flow pathway was unobstructed by twists or what have you. After getting good flow, the gun was opened up fully and a bubble began to form in the end of the balloon.
More helium is going into the balloon here, and the bubble is getting a little bigger. The whole filling usually took about 5 minutes, and used slightly more than one ~1900 psi tank of helium.
A much nicer picture of the filling process (photo by Matt Okraszewski). I originally thought this was taken by taken by Anthony from Scott Base. He is a better photographer with better gear than I have, and the difference is amazing. He put together a DVD of various movies, photos, and time lapse sequences from the winter....and I bought a couple copies. Good stuff. He and Christine (from McMurdo) were also married on station this year, in the McMurdo chapel!
More of the filling action. The balloon, as it gets fuller, becomes a huge sail. It gets whipped around violently by the slightest breeze, and it makes you a little nervous. One tiny hole and it won't even come close to reaching the desired altitude. But the whole winter, we never had a single hole. We even launched in 18 knot winds one day...one of several hairy launches we pulled off. Overall, the project was highly successful. We did something like 27 launches. The first flight was a dud, since our radio transmitter device failed half-way up due to the cold. This problem was remedied by adding another heater to each subsequent flight. One other flight was a dud since the little pump inside the ozone sonde failed right after launch. But every single other flight was 100% successful. We did not lose a single balloon on launch, and we got data from every other flight. Because of the somewhat antiquated equipment, recovering the data from the tracking stations at Crary and Cosray was sometimes a real chore. However we ended up getting great data from about 25 straight launches....a record for this type of work here.
Anyhow, back to a typical launch. Here, the balloon has been filled up to the weigh-off point and the fill tube has been cut and tied off. (Photo by Matt Okraszewski)
Now, to attach the payload. Rebecca (left) was the balloon person, who held the balloon during filling and launch. Olivia (right) was the payload person, and did various little tasks with it during this process. One of them was fairly tedious...tying a little knot to attach the payload to the balloon. This required taking off the heavy gloves...not always pleasant in the dead of an Antarctic winter.
Almost ready to go...time out to pose for a balloon hero shot.
Now, to pay out the balloon. We each lined up and walked the balloon out from the tarp, taking care to keep it off the ground and to keep our velcro, watches, and other sharp objects away from it. After we got in a line and declared that we were ready to launch, Rebecca would let the bubble go. The balloon (usually) would just rise out of our hands. But with winds, some agility was required to stay out of its way as it was rising away. Our first few launches, especially those with wind, were a bit nerve-wracking. But we quickly became used to it and the sight of wind whipping around an extremely fragile, expensive balloon as we filled it and walked it out for launch didn't phase us at all.
A random picture of the tracking equipment at Cosray. We had two redundant tracking stations - Crary and Cosray - to receive data from each flight. This was mainly because depending on which way the winds were blowing, the balloon's signal could often be received much better at one place than the other. This also turned out to be beneficial because we'd often have problems with the olde-tyme tracking equipment. Sometimes one station would suddenly develop mysterious problems in the middle of a flight...and we'd have to rely on the other station only. But all turned out well and our data sets were complete.
Terry and his team came down at Winfly to continue the match campaign...as well as launch some of their own payloads. So in a strange twist of fate, the arrival of a grantee group actually made my life significantly easier! This is a picture of one of their payloads...a condensation nuclei (CN) counter. These, along with their sister devices known as optical particle counters, are able to count the number of various sized particles as they rise through the atmosphere. The two payloads are very similar, except the CN counter has the ability to count much smaller particles than the OPC. Condensation nuclei are tiny particles which provide a "starter" surface for atmospheric substances to condense upon and form clouds. The supercooled liquids in the atmosphere don't really spontaneously condense when they get to a certain temperature. For reasons I don't really understand, a nucleus is needed to trigger condensation. Anyhow, the CN counters count these things as well as larger particles - droplets and crystals that comprise the polar stratospheric clouds themselves. OPC's just count the larger particles. By comparing and analyzing the two types of data, much can be learned about the composition of these clouds, which are the breeding ground for ozone-destroying chemical reactions.
Here is a picture from a Winfly launch...with my new camera. This was a pretty day, with nice soft light and Mount Discovery in the background. This is a plastic balloon after helium filling. It's much larger (8x) than the balloons we launched during winter, because its payload is much heavier than the little ozone sondes we launched.
Here is Terry and his crew paying out the balloon.
Here they are attaching the payload. This is a more complex operation than the ones we did. They actually intend to retrieve these payloads, and there are GPS receivers built in to tell them exactly where they landed. The idea is to launch only when the predicted balloon flight trajectory (based on local meteorological data and models) is over the Ross Ice Shelf and within helicopter range. In October, they are going to be flying around the ice shelf to get these payloads...not a bad way to spend a few days.
The complete thing: balloon and payload train. The bright flags are for obvious reasons...to make it stand out better against the white ice shelf surface.
One last picture here - the balloon and hut point, with Vince's Cross and the Discovery Hut.