NASA Arctic Mars Analog Svalbard Expedition FIeld Report: Introductions – 24 July 2006

Hello

My name is Kirsten and I am quite possibly the luckiest intern ever. I began my current job in the Sample Analysis of Mars (SAM) Lab at the Goddard Space Flight Center thinking that I would be working in the lab for the next few months running samples and calibrating instruments in preparation for an astrobiology expedition to the arctic. Truth be told, running samples and calibrating instruments can be a bit mundane. Analysis and thinking about what it all means is the cool part…. I wasn’t overly excited about my new job, but at least my work would be contributing to a cool expedition: a thought that justified hours of potential dullness on my part. I never believed I would actually get to GO.

It turns out I do get to go. ON A REAL EXPEDITION TO THE ARCTIC!!!!! Yikes. Needless to say, I am extremely excited. On a side note, I was surprised to discover that not everybody wants to go to the arctic. In fact, several of the people in my lab think we’re crazy for going. They say it is too cold. There are also polar bears. Lots of them. Recent estimates indicate a polar bear population of 5,000 in Svalbard, which stands in startling contrast to the mere 3,000 permanent human residents.

A Brief History

So where are we going and what are we doing in the arctic? Three scientists associated with the SAM Lab (Paul Mahaffy, Oliver Botta, and myself) are participating in the Arctic Mars Analog Svalbard Expedition (AMASE) led by Andrew Steele from the Carnegie Institute of Washington. AMASE 2006 is a 16-day expedition to visit several Mars Analog sites in Svalbard, Norway, an archipelago north of the Arctic Circle.

The purpose of this expedition is to study an extreme, Mars-like environment on Earth (Svalbard) using instruments and techniques that are either currently scheduled or hope to be chosen for future planetary missions. In this way, we learn how to more effectively use our instruments, analyze the data they produce and learn about the nature of life on Earth.

AMASE 2006 is comprised of scientists from a variety of fields including biology, chemistry, and geology. Many scientists span these subjects and combine the philosophies and expertise of different disciplines. Such interdisciplinary research is increasingly illuminating the complicated world around us and is generating neat sounding professions such as geomicrobiology.

I figure this interdisciplinary is good for someone like me who could never decide on a major in college –I wanted to study everything. I hope someday I can be a microbioastrochemogeologist. Or something like that.

Who is SAM? What is a GC-MS?

Sample Analysis on Mars (SAM) is a suite of instruments going on the next Mars rover, Mars Science Laboratory (MSL), that launches in 2009. SAM consists of a pyrolysis (baking) chamber, gas-chromatograph, quadrapole mass spectrometer, and tunable laser spectrometer. The gas-chromatograph and mass spectrometer are two different chemical analysis techniques that are commonly combined to provide more powerful analysis and referred to as a GCMS. This GCMS portion of SAM is what we will be using in the arctic.

The GCMS works by taking a very small sample of the material you want to identify and volatilizing it so that individual molecules can be carried by a helium gas flow through a gas-chromatograph column. In our case, we heat small powered rock samples to up to 600 degrees Celsius so that organic molecules, which move to gas phase relatively easily, float up off the sample and get blown by a stream of helium into the GC column. The GC column is actually a very long tube with a very tiny diameter that has a particular chemical coating on the inside. The molecules of the volatilized sample bounce down this tube and get stuck to the walls of the tube for varying lengths of time depending on the chemistry of the molecule and the tube coating. Eventually the molecules make their way all the way out of the column, but different types of molecules come out at different times based on their chemistry. As the helium gas carries the molecules out of the GC, they are swept into the mass spectrometer (MS) where they are ionized by an electron beam from a hot filament and then separated by mass. In the end, the instrument produces a graph called a chromatogram showing the amount of each type of molecule exiting the column. Using software we can look at the mass spectra to identify each group of molecules exiting the GC column. Figuring out what substances the mass spectra indicate can be quite complicated. Chemists have spent years running known substances to generate libraries of mass spectra. At this point, the capabilities of GCMS analysis are exceedingly impressive and libraries with hundreds of thousands of molecules are used to identify chemical species.

We can often identify the molecules we observe in rocks, but occasionally come across something that doesn’t have a good library match. Much of the GCMS analysis is done by chemists looking for manufactured chemicals thus existing libraries are full of substances found in common drugs and industrial products. We don’t currently have any large libraries for “obscure organics in rocks” and we certainly don’t have any for “organics in rocks on Mars”. At this point, we really don’t know what organics are on Mars. We have some educated guesses, partly from studying meteorite compositions, but we won’t know for sure until SAM gets to Mars and can measure the rocks directly. While waiting to get to Mars, we are generating libraries here on Earth from Mars Analog rocks with hope that we can prepare ourselves as well as possible to analyze the GCMS data we get from Mars.

In Svalbard we will be collecting and analyzing many Mars Analogue rock samples to add to our library. We will also be working with scientists using other instruments to combine analysis techniques to gain a deeper understanding of how organics and signs of life are preserved in rocks.

Kirsten Fristad
NASA Goddard Space Flight Center