It has been a busy month for Mars missions. Earlier this week, UAE launched the Hope probe, its first mission to the red planet. China’s first Mars mission, Tianwen-1, lifted off on 23 July. But perhaps the biggest of them all is US space agency Nasa’s Perseverance rover mission, which is expected to launch on 30 July, embarking on a seven-month journey to the planet. “In order to send a mission from Earth to Mars, you need to wait for the right moment as the two planets circle around the Sun on their own orbits,” says Prof. Lewis Dartnell from the department of life sciences, University of Westminster, London, on email. “Such a ‘launch window’ only comes every two years or so, so we are seeing a concentration of Mars missions this month,” he adds.
How important is ‘Perseverance’? Perhaps the most sophisticated Mars rover mission so far, it will look for signs of microbial life. Nasa has invested approximately $2.4 billion (around ₹17,880 crore) to build and launch the mission. Prof. Dartnell describes it as a “thoroughly exciting venture” —while earlier missions have helped us learn more about how suitable the ancient Martian environment may have been for the survival of simple, single-cell life forms, he says, Perseverance will go one step further. “Nasa is beginning to focus more on trying to detect signs of past or present Martian life…. The rover is designed to cache the most promising samples—to safely store them for when a subsequent mission can retrieve and return them to Earth for much closer study,” adds Prof. Dartnell.
Aiming for Jezero: The rover is expected to reach Mars by February and land in the Jezero crater, considered to have “high potential” for hints of past microbial life. “It’s like a sink with an ancient delta or riverbed. When Mars had a wetter surface, Jezero would have been a massive water body. Craters are one of the likely locations where you can find layers of sediment. And, inside those sediments, potentially some organic compounds,” says Siddharth Pandey, head of the Centre of Excellence in Astrobiology, Amity University, Mumbai.
Looking for biosignatures: Perseverance is expected to spend one Martian year (about 687 Earth days) exploring Jezero, collecting at least 30 samples. But what kind of biosignatures will it look for? Everything from rock samples to preserved organic molecules. The crater’s ancient lake-delta system offers promising targets of at least five kinds of rock, according to Nasa. Some answers might also lie in “stromatolites”, which have been key in answering questions about Earth’s past. “These are colonies of bacteria that deposit on rocks and feed off them. They are some of the oldest, primitive forms of life. We find these colonies in rocks of all ages. Such rocks can be found in India as well, especially central India,” adds Pandey. “They are very prominent in Australia, Iceland and Greenland too. Down the line, these are the kind of microbial life forms we might find on Mars,” he says. It remains to be seen whether Jezero actually has anything similar to stromatolites.
State-of-the-art technology: While the core mission area is astrobiology, there are seven primary science instruments that will gather data about geology, atmospheric and environmental conditions. Among them is Mastcam-Z, a pair of zoomable cameras to shoot and create high-resolution, 3D panoramas of the landscape. PIXL, which will analyse rock samples, is capable of detecting over 20 chemical elements. Then there is the Ingenuity Mars helicopter, which will be carried in the same spacecraft as the rover: a lightweight, autonomous helicopter that will be used to test powered flight in the planet’s thin atmosphere.
Future manned missions: A key part of this mission is to set the stage for human exploration. For instance, scientific instruments like MOXIE will demonstrate a technology that converts carbon dioxide in the Martian atmosphere into oxygen. In the future, the oxygen created by this technology could be used by astronauts not only for breathing but as rocket propellant. The mission will also study how the atmospheric dust and weather conditions on the planet could affect astronauts and human life-support systems. “Apart from collecting samples for a future mission to retrieve and getting them back to Earth, the Perseverance mission will help identify sites where humans might be sent in the future and have a base on the planet’s surface,” adds Pandey.