Building an Astrobiology Tool Kit
Testing instruments for ExoMars and Mars Science Laboratory
How can we be sure that instruments that will be sent on future Martian missions will work properly? How do we know that they will obtain accurate and precise measurements? How will we be able to compare the data to what we have seen on our planet? The answer is easy: by testing, testing and again testing them during field trips on Earth. This has been one of the most important goals of AMASE 2009.
During the AMASE 2009 expedition many different instruments to be sent to Mars have been tested in the course of a series of field deployments. The instruments were used to study specific sedimentary and igneous environments. Several of these instruments have been on AMASE before and the instruments are evolving year by year; they become smaller and more compact, but still remain accurate and are better and better at working under the harsh conditions of the arctic climate. Let's see some of the results that we have achieved this year:
Paul Mahaffy, the principal investigator of SAM, works at the Solar System Exploration Division at NASA Goddard Space Flight Center. This year he has used SAM to study carbonate samples from the Sverrefjell volcano and has focussed on macromolecular carbon (MMC) associated with magnetite in the carbonate globules found in an ice cave formed after the eruption of the volcano into glacial ice. This material is similar to those carbonates in the Martian meteorite ALH84001, but previous AMASE research has shown that the carbonates on Svalbard - although excellent analogues for ALH84001 - have formed abiotically. However, these studies carried out with SAM have been very useful in better understanding the ability and limitations of this in-situ instrument to distinguish biomarkers.
Another not less important analytical technique is X-ray Fluorescence (XRF), the emission of fluorescent X-rays from a sample due to excitation with high-energy X-rays. By using this technique elemental and chemical analysis can be performed, both from minerals or non-crystalline samples.
Both XRD and XRF are necessary to obtain data about the composition of the Martian rocks and soils, as they can give us information about the past habitability of the Martian environment where the rocks were formed. Although conventional XRD and XRF instruments have the size of a couple of washing machines, the fabulous work of David Blake (NASA AMES Research Center) has lead to the development of a combined XRD and XRF instrument (CheMin) that has the size of a small suitcase and that is capable of doing the same tasks at the highest resolution. All samples obtained during AMASE 2009 expedition have been analyzed with CheMin, another state of the art instrument that will fly aboard NASA's Mars Science Laboratory mission.
Complementary to this the HRC has 4 degrees of view (almost eight times higher resolution than the WAC) and three RGB colour filters. It goes without say any PanCam imaging helping observations and initial characterization of any Martian environment is crucial. To be able to obtain multi-spectral geological imaging, colour and stereo panoramic images, water vapour abundance and dust optical depth measurements are just a few of the fantastic capabilities on this instrument. Finally, PanCam will not just be useful for remote observations but will also very crucial for observing and classifying retrieved subsurface samples before they are sent to the analytical suite for future analyses by the rest of the instruments.
This way the electromagnetic waves can be reflected by the discontinuities of the subsurface. Moreover, the information from this instrument will permit an early interpretation of the materials acquired with the drilling system up to 2 metres of depth. All the areas that were visited during AMASE 2009 expedition for sample characterization and instrument testing have been also studied with WISDOM.
This FTIR was operated by Juan Diego Rodriguez-Blanco (School of Earth and Environment, University of Leeds) and it provided crucial chemical information that, combined with other instruments -Raman, Chemin or SAM- showed us a global mineralogical and (bio)chemical picture, including the possible presence of organics.
How will we know where to go, what sample to choose or where are the really interesting materials that can tell us information about present or past habitability on Mars? And how will we manage if we need to obtain the sample 'as soon as possible' (days or weeks)? All these instruments if onboard the MSR mission will provide first guidance for the 'correct' and most appropriate sample as in concert with each other these instruments represent a miniaturized version of a terrestrial laboratory that researchers use for their daily work. Naturally for any MSR selection the scientists on Earth will depend on them to decide what actions to take.
For that reason, the reliability and accuracy of instruments like the PanCam, SAM, CheMin, WISDOM, Raman or FTIR will be decisive for the success of the next missions to the Red Planet.
Searching for Martian life... on Earth. And farewell, Svalbard!
Imagine the following mission scenario: we have been able to send a Mars Sample Return mission to the red planet. A rover has characterized the landing site with many remote and contact instruments and has acquired a sample that has been successfully sent back to Earth. This sample, less than half a kilogram of material, could have potentially harboured life in the past on another planet. How do we study this sample in order to search for life?
During the AMASE 2009 expedition many samples from different areas have been obtained and characterized with different instruments to obtain chemical and mineralogical information, but naturally as we prepare for future "Search for Life' NASA and ESA missions, a crucial goal is also to test 'life' i.e., the biology is also one of our primary tasks. Most of the samples that were collected on AMASE come from a harsh environment where only extremophiles can thrive and yet, sometimes we are not even sure whether life could subsist.
Is it possible to find living organisms in high-pressure blue ice, two meters deep, where little liquid water can be found and the only nutrients are small rock particles and some diluted chemicals in the ice? Is it possible for 'life' to survive inside rocks better under extreme cold, dry and high-UV conditions? And if so how do organisms adapt and survive such conditions? These are the same questions that we will ask ourselves when we send the next generation of rovers to Mars.
To assess the diversity of the microbial community structure in an arctic ecosystem our Bio-group - primarily Verena Starke, Mihaela Glamoclija and Adrienne Kish from the Carnegie Institution of Washington - have worked with different techniques and protocols, which include (1) standard genetic techniques to identify and characterize microbial populations (Polymerase Chain Reaction, PCR), (2) handheld life detection instruments, such as an ATP luminometer - which acts as an assay for overall metabolic activity, and (3) a microchip-based Limulus Amebocyte Lysate (LAL) assay that detects gram negative bacterial cell wall materials (living or dead) and (4) fluorescence microscopy to study stained cells.
By characterizing organisms and their habitats, they were able to pinpoint relevant biosignatures and complement measurements acquired by the other instrument teams. When successful, biosignature correlations strengthen interpretations and may be particularly valuable in the search for life on Mars. For example, we have observed organics that play an important role in the development of life in areas where we would not expect to find them and living organisms (extremophiles) that survive in exceptionally harsh conditions.
At the same time, this sort of research can raise a very basic but critical question: how do we know that we are not contaminating the areas we are studying with our own organics and microorganisms? How will we avoid contaminating Mars with "our own life" when we send a space probe there? The most embarrassing and uncomfortable mission scenario we can imagine is detecting life on Mars that actually survived the trip from Earth to the Red Planet. This task, which is related to "forward planetary protection" is really complicated but crucial and it has been addressed on AMASE since the expeditions began in 2003.
The efforts and multiple tests carried out in the last 3-4 years has been the basis for the development of a field-based cleaning protocol for sampling devices and tools. This work has been recently published in the July 2009 issue of Astrobiology journal. Obviously once this research study was completed and the protocol validated it was crystal clear that all instruments / sampling devices that we use for biological research on AMASE will always be strictly cleaned following this procedure.
Front cover of the Astrobiology journal with AMASE picture: http://homepages.see.leeds.ac.uk/~earlgb/Publications/Astrobiology_cleaning_rover_cover.jpg
AMASE 2009 was not an easy expedition to organize: many scientists working together with different backgrounds who need to transport tons of equipment, keep strict timetables, deal with logistics, schedules, accommodation... However, AMASE 2009 was successful because everybody did their best, both individually and also as a group, but also because there were people that worked really hard to make it happen.
We don't need to specify their names as we all know who they are and they know that we really appreciate their efforts. They used their personal time to put everything together, doing a great job in creating a really good working environment and make people feel comfortable and confident both in the success of their individual research tasks but also with "life" in an unusual environment like the Arctic. And they did well. AMASE 2009 could not have been better: people, science and last but not least impressive and unforgettable landscapes.
Now, more than a month after the expedition is over the science naturally continues. Analysis of the data obtained in Svalbard is on course and further sample characterization in the various labs is going on furiously. The results are slowly but surely being obtained, abstracts are being sent to different scientific conferences and papers are being written.
But our minds and hearts are still in Svalbard, which is not only a link with science, but a so beautiful and impressive landscape that we will never forget. The mountains and glaciers, the cold wind, the midnight Sun, the icebergs, the volcanic areas, the silence, the fog over the glacier valleys, the strangeness of a place that sometimes seems to have been taken from another world... all is magical and 'AMASEing'.
After finishing this great expedition there is no day I don't wonder how the landscape looks like today, how the weather is in Wahlenbergfjorden or in Bockfjorden, how far could we see from the top of Sverrefjellet volcano or how the landscape looks like in the glaciers near Ny-Alesund, now that the days are getting shorter. Svalbard will be in my mind for the rest of my life. I should be grateful. And I am.