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Expeditions IceBite Blog: Trek to University Valley
IceBite Blog: Trek to University Valley
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Mars
Posted:   12/23/10
Author:    Margarita Marinova and Andrew Jackson

Summary: NASA´s IceBite team was in Antarctica this month to test a new drill for use on a possible future mission to Mars. In this blog entry, Margarita Marinova describes preparations for the trip to remote University Valley. Team member Andrew Jackson writes about his focus on perchlorate, a compound also in the soil of Mars.

Preparing for University Valley
By Margarita Marinova

Wayne Pollard battling the cold. Yes, it was that cold. Credit: M. Marinova

We have spent the past week getting all of our equipment ready: sleeping bags, personal tents, work tents, food, drilling equipment, weather stations, buckets, sterile bags, batteries, generator, gas, core barrels, hand drills, stove, tables, chairs, water, and on and on and on. 4,000 pounds (2,000 kg) later, we are waiting by the helicopter pad in McMurdo Station for our flights to University Valley. It will take 3 or 4 flights to get all of our equipment over there.

How does all of this equipment get arranged? Months before we travel to Antarctica, we fill out a request for support with the US Antarctic Program which runs all US science and technology activities in Antarctica, and in turn is part of the National Science Foundation. With the support requests in, the different departments in McMurdo – and the other stations around Antarctica – can start allocating equipment. There are many science groups in McMurdo every year and it takes a lot of time and effort to assign all the equipment!

University Valley at night, where during the southern summer the Sun never sets. Credit: M. Marinova

By the time we arrive in McMurdo, this equipment is put aside for us in our designated storage area – as if by magic! We still have to double check that we have everything we need, and inevitably there will be new things that we thought of since the request was put in. Before we get to fly out, our more than 4,000 lbs (2,000 kg) of equipment also have to be packed, secured, weighed, and carried to the helicopter terminal.

The day of the flights is always long. Loading all the gear into the helicopter, then unloading it all at our field site, then setting up all the work tents, kitchen area, food, then personal tents – and then still having some energy left over to cook dinner! And this year we seem to be in for a surprise – it’s quite a bit colder than last year!! About 10 degrees Celsius (18 degrees Fahrenheit) colder, to be more precise! That makes the temperature at night about -25°C (-13°F), with highs during the day of about -19°C (-2°F).

As we sit down for dinner (everybody’s starving!), we start our discussion of all the science that needs to get done. We fill in our white board with all the major to-do items – and they barely fit on there. Our first priority is to set up the prototype Mars permafrost drill and get that working: for the first few days all of us will be there to help Kris and Gale whenever needed. Next we have soil sampling and salt analysis for Andrew, and Wayne will be mapping the buried glacier area and doing some more exploration of University and Farnell Valleys. Alfonso is in charge of getting all the core samples for geochemistry and biology. And I’ll help with the biology samples, as well as taking care of all our weather stations and climate instruments. Also, with the help of everyone else, I want to map the depth to ice-cemented ground of University Valley and the 3 valleys around it. We have a general plan of attack, and some idea of when we plan on doing the longer hikes and more difficult sampling. But in reality we just have to take everything one step at the time – based on equipment, weather, and how all the projects are going.

The team and our gear just after being dropped off in University Valley. Credit: Kris Zacny

It’s going to be a busy 2 weeks, but first we have to see how sleeping in -25°C is going to go! I’m ready with my hot water bottle to help keep me warm during the night.

Searching for Perchlorate in Antarctica
By Andrew Jackson

I am here to look for perchlorate and try to understand why it is here, how much is here, and if I am lucky, the composition of its stable isotopes. Perchlorate, if you are wondering, is the anion ClO4- (a chlorine atom connected to four oxygen atoms). It has a number of unique properties, but is best known for its use in solid rockets as an oxidant – similar to the role that oxygen plays in car engines.

My interest is in natural perchlorate, which is perchlorate produced in the atmosphere. I am interested in it as it may have important implications to atmospheric chemistry, the evolution of life, and the potential for life on Mars! I know there is perchlorate in this valley as another scientist previously reported its presence.

Digging for perchlorates. Andrew Jackson sampled soils to measure the concentration of perchlorate at various depths. The texture and composition of the soil, which changes with depth, tells us about the movement of water in the soil. This indicates what layer he should sample to get the largest amount of perchlorates. Credit: M. Marinova

Unfortunately, I cannot measure perchlorate in the field. However, I do know that its occurrence is strongly related to the presence of nitrate (NO3-). Nitrate I can measure with some very handy test strips. Basically I add water to soil, shake, dip the test strip, and the color indicates how much nitrate is present. The more nitrate that is present, the more perchlorate should be present.

I need to find some material with a good bit of perchlorate as I need 10 mg to measure its stable isotopes. Ten mg is not very much (a couple of salt grains) but in general surficial material only has 1-100 micrograms/kg of perchlorate, which means I would need to collect 100-10,000 kg (220-22,000 lbs) of material. Of course this is not very practical given I have to dig up this material by hand and first fly it to McMurdo by helicopter and then ship it to Texas Tech University; thus the nitrate test strips.

I notice that many of the surface rocks have salt accumulations on the side that touches the soil. After much testing it turns out that this is most likely sulfate (SO4-2) and the nitrate is richest in the soil right under the rocks.

Ten days later…

So, I spent the past 10 days picking up rocks and scraping the soil attached to them into a bucket. A few thousand rocks later, I have a bucket half full of salty sand. I tested the material for nitrate content, and eureka! It measures 2 to 5% nitrate, well more than I expected, and hopefully guaranteeing I have more than enough perchlorate. Now all I have to do is to repeat the process for a duplicate sample.


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