NASA’s search for life on Mars: A rocky road for rovers, a long slog for scientists, and a battle of the budget

Is or was there life on Mars? That profound query is so advanced that it’ll not be absolutely answered by the two NASA rovers now exploring it.

However due to the literal groundwork the rovers are performing, scientists are lastly investigating, in-depth and in unprecedented element, the planet’s proof for all times, referred to as its “biosignatures.” This search is remarkably sophisticated, and within the case of Mars, it’s spanning many years.

As a geologist, I’ve had the extraordinary alternative to work on each the Curiosity and Perseverance rover missions. But as a lot as scientists are studying from them, it can take one other robotic mission to determine if Mars has ever hosted life. That mission will convey Martian rocks again to Earth for evaluation. Then—hopefully—we may have a solution.

From liveable to uninhabitable

Whereas a lot stays mysterious about Mars, there may be one factor I’m assured about. Amid the 1000’s of images each rovers are taking, I am fairly certain no alien bears or meerkats will present up in any of them. Most scientists doubt the floor of Mars, or its near-surface, may at present maintain even single-celled organisms, a lot much less advanced types of life.

As an alternative, the rovers are performing as extraterrestrial detectives, attempting to find clues that life might have existed eons in the past. That features proof of long-gone liquid floor water, life-sustaining minerals and organic molecules. To seek out this proof, Curiosity and Perseverance are treading very totally different paths on Mars, greater than 2,000 miles (3,200 kilometers) from one another.

These two rovers will assist scientists reply some massive questions: Did life ever exist on Mars? Might it exist right now, maybe deep beneath the floor? And wouldn’t it be solely microbial life, or is there any chance it is likely to be extra advanced?

The Mars of right now is nothing just like the Mars of several billion years ago. In its infancy, Mars was much more Earth-like, with a thicker environment, rivers, lakes, perhaps even oceans of water, and the important parts wanted for all times. However this era was minimize quick when Mars lost its magnetic field and almost all of its environment—now only one% as dense because the Earth’s.

The change from liveable to uninhabitable took time, maybe a whole lot of thousands and thousands of years; if life ever existed on Mars, it probably died out a couple of billion years in the past. Steadily, Mars turned the chilly and dry desert that it’s right now, with a panorama similar to the dry valleys of Antarctica, with out glaciers and plant or animal life. The common Martian temperature is minus 80 levels Fahrenheit (minus 62 levels Celsius), and its meager environment is almost all carbon dioxide.

Early exploration

Robotic exploration of the Martian floor started within the Seventies, when life-detection experiments on the Viking missions failed to seek out any conclusive proof for all times.

Sojourner, the first rover, landed in 1997 and demonstrated {that a} shifting robotic may carry out experiments. In 2004, Spirit and Opportunity adopted; each discovered proof that liquid water as soon as existed on the Martian floor.

The Curiosity rover landed in 2012 and started ascending Mount Sharp, the 18,000-foot-high mountain situated inside Gale crater. There’s a motive why NASA selected it as an exploration web site: The mountain’s rock layers present a dramatic shift in climate, from one with plentiful liquid water to the dry setting of right now.

To this point, Curiosity has discovered proof in a number of places of previous liquid water, minerals that will present chemical power, and intriguingly, a variety of organic carbon molecules.

Whereas natural carbon is just not itself alive, it’s a constructing block for all life as we know it. Does its presence imply that life as soon as existed on Mars?

Not essentially. Natural carbon might be abiotic—that’s, unrelated to a dwelling organism. For instance, perhaps the natural carbon got here from a meteorite that crashed on Mars. And although the rovers carry splendidly subtle devices, they can not definitively inform us if these natural molecules are associated to previous life on Mars.

However laboratories right here on Earth probably can. By amassing rock and soil samples from the Martian floor, after which returning them to Earth for detailed evaluation with our state-of-the-art devices, scientists might lastly have the reply to an age-old query.

Perseverance

Enter Perseverance, NASA’s newest flagship mission to Mars. For the previous three years—it landed in February 2021—Perseverance has been trying to find indicators of bygone microbial life within the rocks inside Jezero crater, chosen because the touchdown web site as a result of it as soon as contained a big lake.

Perseverance is step one of the Mars Sample Return mission, a global effort to gather Martian rock and soil for return to Earth.

The instrument suite onboard Perseverance will assist the science group select the rocks that appear to vow essentially the most scientific return. This will likely be a cautious course of; in any case, there could be solely 30 seats on the ride back to Earth for these geological samples.

Finances woes

NASA’s unique plan known as for returning these samples to Earth by 2033. However work on the mission—now estimated to value between US$8 billion to $11 billion—has slowed due to budget cuts and layoffs. The cuts are extreme; a request for $949 million to fund the mission for fiscal 2024 was trimmed to $300 million, though efforts are underway to restore at least some of the funding.

The Mars Pattern Return mission is important to higher perceive the potential for all times past Earth. The science and the expertise that may allow it are each novel and costly. But when NASA discovers life as soon as existed on Mars—even when it is by discovering a microbe useless for a billion years—that may inform scientists that life is just not a fluke one-time occasion that solely occurred on Earth, however a extra frequent phenomenon that might happen on many planets.

That data would revolutionize the best way human beings see ourselves and our place within the universe. There may be much more to this endeavor than simply returning some rocks.

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