The identification of the presence of ozone and carbon dioxide was made using the ExoMars trace gas orbiter (TGO), which has been studying Mars from the orbit of the planet for over two years. The mission aims to understand the mixture of gases that make up the Martian atmosphere, with a special focus on the mystery surrounding the presence of methane, but scientists have now been surprised and intrigued by the new discoveries, which guarantee, however, that they do not invalidate previous results.
The identification of the new gases is reported in two new articles published in Astronomy & Astrophysics, one led by Kevin Olsen, from the University of Oxford, United Kingdom, and the other led by Alexander Trokhimovskiy, from the Space Research Institute of the Russian Academy of Sciences in Moscow in Russia.
They are in the exact wavelength range where we expected to see the strongest methane signals. Before that discovery, the CO2 resource was completely unknown, and the first time that ozone on Mars was identified in this part of the infrared wavelength range, says Kevin Olsen, quoted by ESA.
The articles reveal new secrets about the Martian atmosphere and will allow a more accurate determination of the existence of methane, a gas associated with biological or geological activity, on the planet.
The Martian atmosphere dominated by CO2, which scientists observe to measure temperatures, track stations, explore air circulation and much more. Ozone – which forms a layer in the upper atmosphere on Mars and Earth – helps to keep the chemistry of the atmosphere stable. Both CO2 and ozone have been seen on Mars in previous missions, such as ESA's Mars Express, but the sensitivity of the ACS (Atmospheric Chemistry Suite) instrument in TGO was able to reveal new details about how these gases interact with light.
Scientists had previously mapped how ozonemarciano varies with altitude. So far, however, this has occurred largely through methods that depend on gas signatures in the ultraviolet bands, a technique that only allows measurement at high altitudes (more than 20 km above the surface). The new results from ACS show that it is possible to map Martian ozone also in the infrared, so that its behavior can be investigated at lower altitudes to create a more detailed view of the role of its role in the planet's climate.
"We are actively working on coordinating measures with other missions", clarifies Kevin. "Rather than challenge any previous claim, this discovery is a motivator for all teams to look more closely – the more we know, the deeper and more precisely we can explore the atmosphere of Mars."
The origin of methane on Mars has been studied by other ESA missions, such as Mars Express, from the orbit of the red planet, but also with NASA's Curiosity rover on the surface, and continues to intrigue scientists. Although it is also generated by geological processes, most of the methane on Earth is produced by life, from bacteria to cattle and human activity. Detecting methane on other planets, therefore, "extremely exciting". This is especially true, considering that the gas decomposes in about 400 years, which means that any methane present must have been produced or released in the relatively recent past.
ExoMars was launched in 2016 for Mars in cooperation with the Russian space agency, and takes Portuguese technology on board, following in the footsteps of Mars Express, which has orbited the planet for a decade and has identified variations in the methane in that planet's atmosphere. discovery that set the tone for the launch of ExoMars, which will measure the gases in the atmosphere of the red planet over the next few years.
"These analyzes set new standards for future spectral observations and will help us to draw a more complete picture of the atmospheric properties of Mars – including where and when methane can be found, which remains a key issue in exploring Mars," argues Hkan Svedhem, responsible by ESA's TGO project. "Each piece of information revealed by the ExoMars Trace Gas Orbiter marks progress towards a more accurate understanding of Mars and puts us one step closer to unraveling the remaining mysteries of the planet"
Mars is on the route of major space exploration missions, and after the launch of two probes last week, one from the United Arab Emirates and one from China, this week NASA will launch yet another mission to Mars with the Perseverance rover that joins to other explorers who have been traveling the red planet.