Exploring the Red Planet with Perseverance
The Perseverance rover of the Mars 2020 mission, a project involving Bordeaux-based researchers, is scheduled for launch at the end of July. Before take-off and once the rover has landed in February 2021, their work will cover a number of different aspects. An explanation in two parts. Step 2: Exploring Mars
After a seven-month journey, NASA’s Perseverance rover will land on the Red Planet in February 2021, as part of the Mars 2020 mission. It will land on the Jezero crater, which measures 45km in diameter and is the result of a meteorite impact. This crater contains a former river delta, which flowed into a lake 3.5 billion years ago. The mission, which involves scientists from the Centre for Intense Lasers and Applications(CELIA – CNRS, CEA and the University of Bordeaux) and the Bordeaux Astrophysics Laboratory (LAB – CNRS and the University of Bordeaux), chose this site for its promising geological context with the presence of various rocks and minerals, including carbonates. These carbonates may potentially contain traces of fossilized life, which is the primary aim of the mission, with a view to bringing samples back to Earth in early 2030.
Perseverance is equipped with seven devices, including SuperCam, a French-American instrument on which the Bordeaux-based researchers worked. “It will investigate the geology of soils and rocks, and will play a crucial role in the selection of samples for collection”, explains Philippe Caïs, CNRS research engineer at LAB and project head of the French side of SuperCam. “Once the rover has landed, the engineering team I belong to will have 90 days to carry out checks and settings on the instrument for scientific use.”
The exploration of the surface of Mars can then begin. “Martian rocks are composed of the same elements as on Earth”, Philippe Caïs adds. “Equipped with a laser, three spectrometers, a camera and a microphone, SuperCam will enable us to study their chemical and mineralogical composition in detail.”
SuperCam, the “Swiss knife” of Perseverance
“With the LIBS* technique, we will emit an infrared laser beam onto the surface of the rocks, which will create tiny explosions enabling solid matter to be transformed into plasma”, explains Bruno Bousquet, Professor of Physics at the University of Bordeaux and leading his research at CELIA. “The atoms and ions present in the plasma will de-energize by emitting a characteristic light, which will allow us to identify them.”
The scientists will also be using the RAMAN** spectroscopy technique. “This time, we will emit a green beam with the same laser, so we can vibrate the molecular links of target samples”, adds Élise Clavé, doctoral student in physics at CELIA***. When applied to rock analysis, this technique reveals details of the structure of the minerals which compose the rocks. “This is the first time the technique will be implemented on another planet. It also has the advantage of being able to detect the presence of organic matter.”
The scientific team will also work with a third spectroscopy technique, which will analyze, in infrared, the light of the Sun reflected by the rocks. This technique offers an excellent level of complementarity with the two other techniques. A high-resolution color camera will provide information on the geological context. Lastly, the SuperCam microphone will record sounds caused by the impacts of laser shots during the LIBS analyses, providing information on the nature of the rocks (porosity and hardness, etc.).
“SuperCam is a remarkable instrument” says Bruno Bousquet. “With the same laser, we will be able to pool techniques and obtain co-localized data.” More specifically, the role of the duo formed by the physician and Élise Clavé will be to analyze spectrums and propose data analysis strategies to the mission’s geologists, with whom they are working closely to facilitate interpretation.
Nevertheless, working with a rover operating seven instruments at a distance of 78 million km and a team of colleagues based in several time zones is not a simple matter. Bruno Bousquet explains that an operational team has been set up to ensure the scheduling and daily follow-up of SuperCam’s activities. “Requests made by each team will be classified according to priorities in terms of scientific interest, but also with regard to maneuvers and related electrical resources.” A scientific operation center will be set up at the CNES in Toulouse, to enable both on-site and remote work.
Interplanetary remote working
So, what are researchers expecting to find on the surface of Mars? Élise Clavé points out that “a great deal of thought went into choosing the landing site, in order to provide the best possible conditions for the preservation of exo-biological traces, if they exist.” However, she also explains that “the robot mission alone will undoubtedly not allow us to determine their presence, which is why the focus is on the collection of samples presenting the best characteristics, with the aim of bringing them back to Earth on a future mission.”
Beyond the search for forms of previous life, scientists are also very keen to understand the evolution of Mars’ surface over millions of years. “By investigating the formation and development of planets in the solar system, we can find keys to understanding our own planet”, Élise Clavé says.
The initial duration of the Perseverance mission is at least one-and-a half Martian years, i.e. around 1,030 Earth days. However, if all goes well, Perseverance, like its predecessor Curiosity, which has been operating on Mars’ surface since 2012, could explore the Red Planet and provide scientists with data for many years to come.
*LIBS – Laser induced breakdown spectroscopy
**RAMAN - RAMAN spectroscopy is implemented, like LIBS, up to a distance of 7m. The RAMAN signal lasts only a few nanoseconds, for the duration of a laser pulse.
***Élise Clavé’s thesis is funded by the CNES and the Nouvelle-Aquitaine Regional Council.
Mars 2020 mission: ready for take-off!
Summer 2020 will mark a new step in NASA’s Mars 2020 mission with the launch of the Perseverance rover to the Red Planet. Scheduled for take-off between July 30 and August 15, this launch will be carried out with an Atlas V rocket from Cape Canaveral in Florida. Perseverance will be equipped with the French-American SuperCam instrument, which the scientists from the Centre for Intense Lasers and Applications and the Bordeaux Astrophysics Laboratory have been working on for several years. Perseverance is currently at the Kennedy Space Center and is awaiting the green light to begin its long voyage. Owing to the Covid-19 epidemic, the French teams will unfortunately not be able to attend the launch. Landing on Mars is scheduled for February 18, 2021.