Ten years of the Planetary Fourier Spectrometer (PFS)

Today’s post – part of a series of reports marking the MEX 10th anniversary – was submitted by Marco Giuranna, the Principle Investigator for the PFS instrument. Marco works at the IAPS Istituto di Astrofisica e Planetologia Spaziali (INAF), Rome – Ed.

It’s been ten years since Mars Express was launched on 2 June 2003. Ten years full of exciting moments, challenges, and beautiful memories. I could never forget that moment.

It was 10 January 2004. We were all insidem a small room at the European Space Operations Centre (ESOC), Darmstadt, Germany, in the very early morning hours. It was very cold outside, something like -10°C, or even colder. All the PIs for the various instruments were in that room, together with a couple members of each science team. I was among them, as a member of the Planetary Fourier Spectrometer (PFS) team. We were all waiting for the very first observation of Mars!

At that time, Vittorio Formisano was the PI for PFS. I was only a young student. I was responsible for the calibration of PFS; in other words, I had to transform the raw data sent by the instrument into quantitative measurements of Mars.

The room was silent, with only some whispering here and there. “Will the instrument switch on? Will it work properly?” I bet everyone was wondering the same questions.

All of a sudden: sounds of keyboards everywhere, people running around talking loudly… It took me a few seconds to realize what was going on: the first data were arriving!

We checked our data… everything was OK and PFS was working well. Everyone was so happy!

Everyone, except me.

Well, it’s not that I wasn’t happy. Of course I was, but an additional challenge was awaiting me: calibration.

Will the algorithms developed in the laboratory work also for Mars? I couldn’t answer that question – I was so nervous. But the moment has come. I got the data and loaded them into the software. All I had to do was to press the ‘run’ button… and hope for the best. Click.

“Mars is warmer than the Earth!” I shouted.

Single PFS measurement of Mars acquired during the very first set of observations around the equator, January 2004

Single PFS measurement of Mars acquired during the very first set of observations around the equator, January 2004. The signal around 1300 cm-1 gives a first estimation of the surface temperature: 285K.


Yes! The calibration was successful!

The first PFS observations of the Red Planet passed over the equator, and allowed a first estimation of the temperature of the surface there: around 285 K (~12 °C), much warmer than in Darmstadt!

I was so happy, I took a screenshot of the first calibrated measurements of PFS and sent it by email to all the Co-investigators around the world. I will never forget the expression of Vittorio. After all those years of hard work, his instrument was finally observing Mars!

Since then, PFS has collected almost two million measurements of Mars, allowing analyses of its atmospheric composition, circulation and climatology: ten years of top-quality science and exciting results. Who could imagine that a little feature observed in the PFS measurements would have led to one of the ten most important discoveries of the last years, and of Mars Express: methane on Mars!

First detection of Methane with PFS. Credit: ESA/IANF/IAPS

First detection of methane (CH4) with PFS (adapted from Formisano et al., 2004. Science 306, p1758).

PFS is still operating and will continue to monitor the Martian atmosphere for new, exciting results.

Happy Birthday, Mars Express!

Student of Mars

Today’s post – part of a series of reports marking the MEX 10th anniversary – was submitted by planetary geologist Damien Loizeau, who is on the hunt for water on Mars – Ed.

Damien Loizeau

I got involved in Mars Express when I started my PhD. Mars Express had been in orbit for a bit more than a year, the first results had just been published, and lots of new and exciting data were transmitted every week. Now I am part of two instrument teams for the mission: OMEGA, the imaging spectrometer, and HRSC, the high resolution stereo camera.

I work on the geology of the surface of Mars and these two instruments are perfect to study it. OMEGA helps us to determine the mineralogy of the surface, that is, the composition of the rocks, and we try to understand the age and the formation of the geological units with HRSC.

It was the first time that we had such a large dataset to understand the geology of Mars, and I was starting my scientific career inside this flow of new discoveries.

I could meet many of the leading European and American Mars scientists during the Mars Express instrument team meetings, where the most recent discoveries were presented and discussed. I also had the chance to work directly with the principal investigators of OMEGA and HRSC, in Orsay (France) and Berlin (Germany), respectively.

My first focus was on identifying minerals formed with liquid water. Liquid water is crucial for life on Earth, and it’s of utmost importance to evaluate if Mars was habitable, and if life had a chance to develop there. We mapped clays in different regions of Mars with OMEGA. On Earth, clay minerals mainly form over long periods by the interaction of rocks with liquid water. With the help of the orbiting high resolution cameras like HRSC, we observed that almost all the clay detections corresponded to rocks formed in the very early Martian history. This is a major sign of the drastic climate change that the Red Planet suffered more than 3 billion years ago.

I had the opportunity to make the map below for one of the Mars Express press conferences to illustrate our work, and I have been very happy to see it circulating on the web and in conferences for many years since.

Perspective view of clay-rich rocks (blue) on the old plateaus around the valley of Mawrth Vallis (left) and the crater Oyama (centre), made from a compilation of OMEGA, HRSC and MOLA (NASA Mars Global Surveyor) data. Credits : ESA/OMEGA/HRSC

Lately I had the opportunity to work for two years in one of ESA’s centres – ESTEC – in the Netherlands. I could follow more closely the missions with the scientists in charge of them, and the future projects like ExoMars. It was quite different from the academic world, with lots of new acronyms to remember!

Today, with the help of the instruments of the NASA Mars Reconnaissance Orbiter, we are discovering the diversity of environments were liquid water has been present in the past on Mars, not only at the surface, but also at kilometre depths. But there is still a lot to discover both within the datasets from the spacecraft still in orbit around Mars, and from future missions. Exciting times lie ahead!