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The Antarctica Diaries: week five

It’s hard to ignore Antarctica’s natural beauty, especially when ice halos come out to play. Michael Ashley

Professor Michael Ashley is currently in Antarctica to deploy a telescope to one of the most remote locations on Earth – a place known as Ridge A, some 850km from the South Pole.

This is the fifth instalment in Professor Ashley’s Antarctica Diaries. To read the previous instalments, follow the links at the bottom of this article.

January 9 – Airdrop, or not

An “airdrop” is where an aircraft flies over and, rather than landing, drops cargo using parachutes. This isn’t all that useful during summertime, where it is easier just to land an LC-130 on the ice. But during winter (when it’s not possible to land due to low ground temperatures which freeze the aircraft’s hydraulics) an airdrop can be the only way of getting urgent cargo such as medical supplies to the Pole.

For the past week, a C-17 aircraft has been waiting at Christchurch for the weather to be good enough for an airdrop. The C-17 will fly non-stop to the Pole, drop its cargo, and then head back to Christchurch.

Early this morning, after several false starts, the C-17 started its long journey south, and just after breakfast a group of 50 of us waited about 500 metres from the station to witness the airdrop. By all accounts it can be quite spectacular.

Folks gathering to watch the C-17 airdrop. Michael Ashley

Within five minutes of the appointed time, we heard the thundering roar of the C-17’s engines. Somewhat concerningly, there was a fairly thick layer of cloud, perhaps 300 metres above the ice. We saw signs of the contrails from the aircraft in the clouds, but then the thundering roar petered out and we heard the announcement: “The airdrop is cancelled”.

Apparently the C-17 made a pass over the Pole, couldn’t see the ground from 1,000 feet (300 metres), so turned around and went back to Christchurch. Disappointing, but those are the safety regulations.

Coincidentally, a Twin Otter landed a few minutes later, and the 50 of us waved at it – the pilot must have wondered why we had all made the effort.

A Twin Otter just about to touch down on the skiway. Michael Ashley

Walking back to the station we passed through the cargo berms where “stuff” is stored, possibly for future use, possibly to be taken back north, to warmer climes.

Some of the cargo berms near the station. Michael Ashley

I discovered later in the day that the bacon that’s been served in the galley for the past week was recently found on the berms, and dates from 2003! It did taste a little odd.

Moving snow to stop buildings being covered is a never-ending job. Michael Ashley

While we continued work on our experiment, a couple of skiers were just making it to the Pole. They had spent 64 days retracing Roald Amundsen’s route from 100 years ago, when he led the first expedition ever to reach the South Pole. One of these skiers will give us an evening lecture in days to come.

January 10 – Diamond dust halos

Precipitation at the Pole comes in two forms: smallish snowflakes or “diamond dust”. The latter are extremely small cylinders of ice that glint brightly when they reflect sunlight. If you have sufficiently large numbers of these cylinders present, you can get a series of beautiful halos around the sun. The earliest to appear are “sun dogs” – bright monochromatic patches at a fixed angle from the sun. As the diamond dust intensity increases, so does the complexity of the phenomenon, with all sorts of additional arcs, inverted parabolas, rainbows, and so on.

Today, for a period of about ten minutes, conditions were perfect: a deep blue sky for contrast, no clouds, and large quantities of diamond dust. We witnessed the best display of atmospheric effects I have seen. I didn’t have my super-wide angle lens with me, so I couldn’t do full justice to the event, but hopefully these photos will give you some impression.

Luke blocking the sun, with an incredible display of ice halos around him. Michael Ashley
The uppermost halo in the previous image. Individual particle of “diamond dust” are visible. Michael Ashley

At lunchtime we said goodbye to Yael (University of New South Wales) and David (University of Arizona) whose time at the Pole is now up. They both made invaluable contributions to the project.

The LC-130 taking David and Yael back to McMurdo. Michael Ashley

The flight they are leaving on brings in Loomy, our mountaineer guide, who will accompany us to Ridge A. Loomy is basically an Alaskan version of Bear Grylls, the British survival expert and daredevil extraordinaire.

Loomy has some great stories to tell, including how some years ago there was a medical emergency at the Pole in mid-winter. He was part of a small team of people (including a surgeon) who were needed to make a mid-winter airdrop (cargo and themselves) over the station.

The plan was cancelled at the last minute when a Twin Otter aircraft was able to land at the Pole and take the stricken person back out to safety. The Twin Otter has an advantage over larger aircraft in that it doesn’t use hydraulics to operate its control surfaces. This means it can land at temperatures well below -50ºC. Still, the incoming crew had to face the real prospect of having to spend five months on the ice if they couldn’t take off again.

Talking of aircraft problems, an LC-130 was doing pre-flight checks prior to leaving the Pole last night when it was discovered that its ailerons and tail rudder were inoperative. This is a very serious malfunction, and if it occurred during flight you would be reaching for a parachute. For the time being, this “Herc” will be staying at the Pole for repairs.

The LC-130 with mechanical problems, parked at the Pole. The two domes house microwave dishes for communication with near-geostationary satellites. Michael Ashley

January 11 – Fuel at Ridge A, and HEAT into the Polar Haven

At 7am each day the Twin Otter pilots meet at COMMS (South Pole communications headquarters) and receive their flight instructions for the day. There are multiple options available, depending on weather, and everything coalesces into a plan at 7am.

This morning there is bad weather at several sites, so we are given the go-ahead to take four drums of fuel to Ridge A.

An important milestone is reached in the afternoon with our HEAT telescope (High Elevation Antarctic Telescope) joining PLATO-R in the Polar Haven tent. We now have a complete system to test, and things are looking promising.

Meanwhile, I am involved in some additional work on the side which I haven’t yet told you about. PLATO-R is just the latest of our PLATO remote observatory systems on the Antarctic plateau. We have PLATO-F in collaboration with Japan at Dome F, and the original PLATO and PLATO-A in collaboration with China at Dome A. One of my jobs is to write the software and keep track of the day-to-day performance of these observatories.

PLATO-A is particularly tricky. It was newly built at the University of New South Wales late last year and is being installed by a Chinese traverse team at Dome A (about 150km from Ridge A) right now. We only had a few days to test the software before shipping.

Supporting the Chinese at Dome A involves me in numerous Iridium phone calls to Dome A and lots of delicate communication with the PLATO-A computers to make sure the experiment is stable and working correctly.

Here’s an example of what can go wrong. If a diesel engine is started without proper software in place to monitor temperatures and battery state-of-charge, it is easy to irrevocably damage something. Working on this from my room in the South Pole station over two, slow, intermittent Iridium links (one from the South Pole to the ground-station in Hawaii, the other from Hawaii to Dome A) is quite a strain.

January 12 – Diesel engines, small and large

Andrew, one of the station’s diesel mechanics, visited the Polar Haven today and cast his expert eye over our two little diesel engines. When going flat-out, we can generate about three kilowatts of electrical power. Andrew is used to the working on the megawatt diesels that generate power for the station.

When the station’s power plant was first commissioned, it was level with the surrounding ice. But some 20 years later it is now almost entirely buried under the snow.

Andrew has promised me a tour of the power plant, so for all you diesel aficionados out there, expect some more photos and discussion soon.

The megawatt diesel power plant for the station is buried under the snow. Michael Ashley

While tweaking the throttle settings of our diesels in the afternoon, we happened across a problem that we hadn’t seen before: the alternator output voltage is just a little too high for the controller unit when the batteries are at their lower voltage limit. In effect, this means we can’t control the load on the engine. The only workaround is to run the engines slightly slower than we would like.

And another surprise: the exhaust gas thermocouple on one of the engines has become intermittent. Fortunately we have a spare and are able to swap it in fairly quickly.

Sorry to dwell on all these instrumental minutiae, but these are the typical sorts of issues and failures that we have to deal with. The real skill in designing PLATO-R to operate remotely for a year is to build in sufficient redundancy, and sufficient re-configurability, to be able to cope with problems as they arise during the year. With our original PLATO at Dome A, which has operated continuously for over three years now, we have had numerous electrical and mechanical issues. But in all cases, we have been able to reconfigure the software to cope.

The weather today was rather miserable. Lots of low cloud which had the effect of making it very difficult to discern the boundary between the snow and the sky.

White out conditions. Somewhere in the middle of the photo is the boundary between the snow and the sky. The black rectangles are skiway markers. Michael Ashley

January 13 – Stranded at Ridge A?

This morning at breakfast I met up with Gary, the Twin Otter pilot who will most likely take us to Ridge A. Gary and his co-pilot took four drums (800 litres) of AN-8 fuel to Ridge A for us two days ago.

The trip turned into quite an adventure they don’t want to repeat.

The snow surface looked satisfactory from the air, but turned out to be very bumpy when they landed. So much so, that after unloading the drums of fuel they were unable to take off. Closer inspection revealed that the surface consisted of an icy crust of variable thickness over a powder base. Gary surmised that the very low air speed at Ridge A allowed the snow to be warmed by the sun, to the point where it started to solidify somewhat. But the real issue was that the ice patches formed undulating bumps that made it impossible to reach take-off speed.

There was nothing for it but to manually dig out a runway. Gary and his co-pilot spent the next three hours using shovels to take the icy patches off 500 metres of runway. At a pressure altitude of 4,480 metres (14,700 feet) this was not an easy task. With a full load of passengers the Twin Otter would need over 900 metres of runway.

This presents us with a problem: we will now need to take a snow groomer (a mechanical device that attaches to a skidoo) to Ridge A before we can take our team in. And in a twist of fate, the only suitable snow groomers at the Pole were returned to McMurdo Station last week. This means we’ll have to wait for an LC-130 flight to bring them back. To top it off, we’ll need to get permission from the US National Science Foundation to have an additional Twin Otter flight to deploy our experiment.

Another problem surfaced in the afternoon: the three Iridium modem SIM cards we will be using to control our experiment remotely have a subtle problem with their “provisioning”. The bottom line is that our modems will not make an internet connection to the Iridium ground-station. We hadn’t realised this problem before since we are in a radio-quiet area of the station and we have to obtain special permission to test the satellite communication.

Fortunately, a few urgent emails to the appropriate people in the US resolved the situation, and we were online late in the evening.

Walking back to the elevated building around midnight, I took a photo of the entrants in the ice sculpture competition. Some large blocks of snow have been dumped near the station, and several teams of people are competing for the best sculpture, using electric chainsaws and slower manual techniques. So far, the winner looks to be the giant couch, with a dummy dressed in Extreme Cold Weather gear, but the shark looks pretty good too.

The ice sculpture competition. Michael Ashley

January 14 – Banjo Night

With the discovery of the unexpectedly poor runway conditions at Ridge A, Craig is busy writing emails to folks at McMurdo Station to make sure our deployment is not affected. We will need one more Twin Otter flight, which, in a heavily constrained schedule, is asking a lot.

There are suggestions that we change our site to AGAP South, which is an established camp a few hundred kilometres away, but Craig restates the scientific evidence that points to Ridge A being significantly better.

Craig’s logic wins the day, and all stops are pulled out in an effort to send a snow grooming machine to the Pole as soon as possible.

At lunch I sit next to a chap who is involved in straightening the hole going to Rodwell number three. The station gets its fresh water by melting ice in underground caverns known as Rodwells, after Army engineer Paul Rodriguez who first came up with the idea. Once a Rodwell is started, it doesn’t take too much energy to keep a large “bulb” of water in a liquid state.

The station is currently using Rodwell number two. Number one is used for waste water and sewerage. Number three is being prepared for use as a drinking water supply, and this involves straightening the 70 metre shaft that leads to the cavern. The engineers lower a heated 250kg weight into the shaft, and gravity naturally melts the hole in the desired direction.

Today being Saturday, it is Banjo Night at the Pole, where a jovial group of several dozen “Polies” get together, bring along any banjos they can find, and then run over them with D8 Caterpillar bulldozers.

Only joking.

But that does give me the opportunity to mention that, as befits a community of 240 people living in close proximity, there is a thriving program of recreational activities here at the Pole, including live music, barn dancing, volleyball, movies and so on.

The South Pole greenhouse. Michael Ashley

January 15 – Will SPUD answer the ultimate question of life, the universe, everything?

Today, finally, after weeks of waiting for suitable weather conditions, Craig’s Stratospheric Terahertz Observatory (STO) balloon experiment was launched from McMurdo (Craig is from the University of Arizona.) STO will have a mission lifetime of up to two weeks as it is naturally blown around the continent by the winds of the Polar Vortex, eventually coming back to Earth close to its starting location. All indications are that the instrument performance is, in NASA speak, “nominal”. That is, nothing has actually caught fire yet.

Meanwhile, at Dome A, my Chinese colleagues are having trouble with starting some engines in our PLATO-A module. It turns out that an incorrect thermistor that measures the alternator temperature has instructed the computer not to start the engines. (This is basically because the computer thinks the alternator is just about to melt, when in reality it is quite cool).

We try various software fixes during the day, but in the end the simplest approach is just to snip the thermistor out of circuit – this works, and PLATO-A is online later in the day.

In the evening we have an absolutely brilliant Science Lecture by Clement Pryke, of the University of Minnesota, on an experiment called SPUD that he is co-leading at the Pole.

SPUD is an ambitious program with the goal of detecting “B-mode polarisation in the cosmic microwave background”. That probably won’t mean anything to you, but put another way, if SPUD makes the detection, it will have found evidence for gravity waves in the universe when it was only 400,000 years old.

That also sounds pretty complex, and the best I can quickly tell you is this is one of the Holy Grails of cosmology. It would be an important piece in the puzzle of understanding how our universe came into being. You can’t get a much bigger picture than that.

Clem’s talk was riveting, and I was not surprised to learn later that he won a teaching award at the University of Chicago a few years ago.

Further instalments in Michael Ashley’s Antarctica Diaries will appear on The Conversation in the coming weeks.

Follow the links below to read the previous instalments:

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