Lionel d'Uston, now a retired CNRS research director, is the only Frenchman to have participated in the March Opportunity mission. While NASA announced its stop on Wednesday, February 13, he agreed to return to this adventure for La Croix.
The Cross: How did you experience the termination of the Opportunity mission, after fifteen years and more than 45 kilometers on Mars?
Lionel of Uston: Of course, when John Callas (the mission manager at NASA, Ed) warned me, it hurt me a little bit. The Opportunity robot was powered by solar panels that were covered with dust during a big storm in mid-June. The cloud was so dense that the panels were no longer charging.
However, the temperatures are very low on Mars, and the electronics must not go below – 55 ° C. Lacking power, Opportunity was too cold. Even though the solar panels may be able to capture the energy now, something has dropped in the meantime and the robot is unreachable. And then there was also his old age! Many instruments did not work anymore, or no longer very well.
The mission has far exceeded its expected duration …
L. of U. : Yes, the goal was to hold ninety soils (days on Mars), or about three months (1). After, there was the Martian winter and the atmospheric dust would be deposited on the solar panels. But good surprise: wind swirls regularly go to the surface and raise the dust. After a few months of mission, when indeed the solar panels were getting dirty, we suddenly had a sweep and the energy production was restarted.
Opportunity, fifteen years of loyal services on Mars
The unexpected "Martian housekeeper" allowed us to continue long! This is also why the storm last June did not worry me so much. I thought he had seen worse … But in fact it was the worst.
Solar panels of the robot Opportunity, here already fouled by a storm in 2007. / NASA / JPL-Caltech / Cornell
What did Opportunity teach us?
L. of U. : For me, the main success is transmitted images (2). After multiple rebounds on Mars and a very distressing tension on Earth, Opportunity arrived in a small sandy bowl. There, from the first photo, we saw rocks that indicated an ancient seabed. These strata and sediments were the visible evidence that there had been, in the past and for a long time, water on Mars. It was great !
Subsequently, there was a plethora of analyzes of different types of rock to better know the past of Mars. There was always a pebble that looked a bit odd two meters away and you had to go see!
The last destination of Opportunity in recent years was the huge crater Endeavor, more than 20 kilometers in diameter. It's a nice place to finish your mission.
Many people have expressed their sadness. Why do we tend to attach ourselves to robots sent to Mars?
L. of U. : It is true that we "humanize" a little Opportunity and other robots. For example, we tend to talk about osteoarthritis when the movements are stuck. I think it's because we focus on their adventures as we go, and we enrich them with the ability to analyze their own situation.
Mars, a land of exploration
To design the first missions to Mars, we spoke of "robot-geologist". So we imagined that the device should replace a real geologist on the ground. All their design is based on human behaviors to reproduce. Then when Opportunity got wet for the first time in 2005, he was taught to take a picture every turn. These photos were only used by the robot, he compared them to previous ones, to see if he was moving forward or if he was on the spot and could become bogged down again.
How did you find yourself on this project?
L. of U. : At the time, I collaborated with the German team of Rudi Rieder who was developing the APXS spectrometer, and I also helped another team across Germany on a Mössbauer spectrometer. Both instruments were finally installed at the end of the arm on the robot Opportunity. So I was involved in the preparation meetings and I continued to participate in the operations.
► Other robots on Mars
Curiosity arrived in 2012, is now alone on the red planet. Although the storm has reduced its visibility, the robot derives its energy from a thermoelectric radioisotope generator and thus remains functional despite the dust.
Two other robots are scheduled to join Mars in 2020. The Europeans will launch the second part of the ExoMars program, with rover Rosalind Franklin. The Americans, they will send the "cousin" of Curiosity, for now baptized Mars2020.