Science and technology
Pierre Beck is a planetary geologist at the IPAG-OSUG, (Grenoble Institute of Planetology and Astrophysics). In 2015, he received the bronze medal from CNRS, the National Centre for Scientific Research.

 Question Box

What does the study of meteorites teach us about Mars?

Pierre Beck: The vast majority of the thousands of ordinary meteorites which fall to Earth are ordinary chondrites. However, there is a much rarer family of meteorites – Martian meteorites. This was one of the research topics for my thesis, and one which I have pursued beyond my studies. I used these Martian meteorites to trace the history of the Red Planet. A number of them have taught us about the origin of Mars’ colour in particular.

Infrared spectroscopy is your preferred method of analysis. What does that involve?

P. B.: It’s an optical technique which offers the advantage of remote use by remote sensing. Light can travel vast distances in astronomical units. Using this technique, we can observe objects which are tens of billions of kilometres away from Earth. What my work is focused on is what we call reflectance spectroscopy. Light from the Sun illuminates objects in the solar system, and we look at that light reflected from their surface. Depending on the chemical composition of that surface, depending on what is present on that surface, depending on the mineralogy; if there is water, if there are certain families of minerals, there will be absorption and, to some extent, colours related to that mineralogy. I characterise these lab samples, I measure the spectra in the lab and I compare them to observations made either from Earth or on space missions. It’s one of my main activities.

You take part in space missions. What is your role in Rosetta?

P. B.: I was part of the work on VIRTIS, an instrument which is installed on the orbiter. I compared the spectra measured by VIRTIS to our measurements on meteorites in an effort to understand whether the material on comets was similar to that which makes up meteorites. The answer is no. What’s driving me at the moment – and I hope to work on this in the years to come – is seeking to understand why these objects are so dark. Comets are the darkest objects in the solar system. Only a very small percentage of the light that reaches them is reflected. It’s something that remains quite a mystery today.

You also have a role in the mission which sent the Curiosity rover to Mars…

P. B.: In 2014, I joined the CHEMCAM instrument team studying Martian rocks actually on Mars using a technique called LIBS (Laser-Induced Breakdown Spectroscopy), which gives us an idea of the chemical composition of surrounding rocks. We are also involved with my Grenoble colleagues in SUPERCAM, a more advanced version of CHEMCAM that measures two more things – infrared and Raman spectra. It’s a highly versatile instrument with great potential. This mission is particularly interesting because its aim is to detect biosignatures, i.e. signs of life. The instrument will be installed on the rover used for the Mars 2020 mission.
Publié le May 17, 2016
Mis à jour le February 20, 2017

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