The Computer Modelling Sedimentation on Mars (CompSedMars) project, led by SUPSI's Department of Innovative Technologies and the Research Group in Physical Geography at the University of Basel as part of the European Space Agency's ExoMars mission, aims to study the composition of the martian surface using a computational approach.

Who is Federica Trudu and what brought her here?

Ever since I was a young girl, I realised that I had a logical mindset, but I also obtained good results at an experimental level. In order to avoid giving up on either aspect, I started specialising in computational methods, and from a professional point of view I am a computational physicist-chemist, working on writing algorithms to deal with physical or chemical systems under conditions that are difficult to reproduce in the laboratory.

What is your educational background and what do you do at SUPSI?

I graduated from the Physics Department of the University of Cagliari, then spent a year as an assistant at the EPFL and took a PhD at the ETH.
At SUPSI I teach Physics and Numerical Mathematics in the Bachelor courses of Ingegneria gestionale and meccanica. From August 2021 I also obtained a two-year research contract with the Università di Basilea.

How did you get in touch with the CompSedMars project?

I have always been involved in the study of minerals in the earth's crust, I like to observe the distortions and changes of atoms caused by subjecting the mineral to a certain temperature or pressure. But all this cannot be seen directly with an experiment, you need a simulation.

In the heat of this passion and the launch of a few rovers on Mars, I wondered what the characteristics of Martian minerals were and how these systems could be studied.
I therefore went to a conference presenting the first rover of the Agenzia Spaziale Europea, renamed Rosalind Franklin, which will be sent to Mars in search of traces of life as part of the mission ExoMars.

On this occasion, I met Prof. Klaus Kuhn, Head of the Physical Geography Group at the University of Basel and a member of the scientific team responsible for calibrating and testing the high-resolution camera (CLUPI) on board the rover that will be used to analyse the sedimentary material on the surface of Mars.

What was and what is your role within the project?

The research group led by Kuhn deals with planetary geomorphology, the study of the shape of the crust, sediments and certain characteristics of the Martian soil. Their approach is purely experimental, they do not write algorithms, and they needed someone to write computational models to simulate how these sediments were transported to a gravity different from Earth's.

Although I had never done anything like this before, I decided to get involved. I started by writing the software for the project, which, in the first instance, only did data analysis: I took their experimental data and processed it to derive the limits of the existing theory. The first conclusion I came to was that examining the Martian data with terrestrial theory leads to an error.

After that, I decided to focus on treating fluid dynamics to understand how sediments such as pebbles interact with water (an easily studied element that according to theory was also present on Mars), and began writing computational fluid dynamics software.

In all this, what are parabolic flights for and what do they consist of?

There are various methods to achieve a gravity different from that of the earth, one of which involves parabolic flights.

During these flights, the aircraft performs a series of parabolic trajectories: it starts from a stationary state, climbs until it reaches the optimum inclination (45-50°) and then goes into free fall for 20-25 seconds before returning to a stationary state. Reduced or absent gravity is not experienced because there is no gravity, but because you are in free fall with the aircraft and have no constraints. Typically, four to five parabolas are performed in a row, at the end of which the aircraft turns around and performs a series in the opposite direction until the planned number is completed.

Last year I made my first parabolic flight. The sensation of reduced gravity is beautiful: it is like flying in a slowed-down time where everyone is floating in the air. Beyond what you might think, however, it is not like going on a merry-go-round. The body is under a great deal of physical and mental stress and during that time we have to stay focused in order to carry out the experiments; it is a very fast experience in which it is crucial to be able to make instant decisions.

What results were achieved in the two experiences?

Our aim is to see if we can use our software to reproduce images that are useful for interpreting the Martian soil. In particular, we measure the sedimentation speed of the particles and, to do this, we need to put ourselves in the closest possible conditions.  

During the first experiment, we only had a frontal camera to see the sediment descending, measure the speed and compare the data. On that occasion, we completed 13 gravity 0 parabolas, 2 Martian parabolas (in reduced gravity) and 1 lunar parabola. Although we performed more than one experiment, two ‘Martian’ parabolas were few because we did not have enough statistics. During the second flight departing from Florida on 12 December, we tried to close this gap by carrying out 30 parabolas: 10 in 0 gravity, 10 Martian and 10 lunar. With two cameras we were also able to obtain the entire 3D pattern.

What is the role of the research institutes of the Innovative Technologies Department?

In preparing the flight, I also had great support from some colleagues in the Innovative Technologies Department, whom I would like to thank personally.

Together with Alberto Vancheri of the Istituto sistemi informativi e networking (ISIN) we started to write a computational fluid dynamics model based on the Boltzmann equation. In recent months, we have also been joined by Luca Diviani of the Istituto di ingegneria meccanica e tecnologia dei materiali (MEMTi) who, within 3-4 weeks, modified the experimental chamber to be able to carry out more experiments. In particular, I want to mention Andrea Marino, a Bachelor's assistant in Master's training and a former student of mine, who played a decisive role. It is wonderful to see the growth of these guys and the many milestones they have already achieved!

What does it mean to be a woman in science and in this project?

The aim is to make people understand that it can be done, that there are examples to follow.
Think of Samantha Cristoforetti, Rita Levi Montalcini, these are women who have done incredible things. There are so many men who have done so many incredible things but women in science have always lagged behind. The beauty of science subjects, on the other hand, must be shown to girls from an early age: examples must be given regularly, without any kind of barrier, only in this way can important cultural changes be triggered!