Roger Wiens is the principal investigator of the ChemCam and SuperCam instruments at the U.S. Department of Energy's Los Alamos National Laboratory. SuperCam is a product of a United States-France partnership, along with support from Spain. Wiens contributed this article to Space.com's Expert Voices: Op-Ed & Insights.
Plenty of sci-fi movies over the decades have shown us fictionalized versions of Mars that include everything from hurricane-force winds (in the critically acclaimed 2015 movie "The Martian") to human-devouring plants (in the universally panned 1959 movie "The Angry Red Planet"). The truth about the Martian surface might not be as dramatic but, I would argue, it is equally as exciting — if not more so, because it's real. And with NASA's Mars 2020 mission set to launch this summer, we're on the cusp of even more discovery.
So far, thanks to a decade of research enabled by NASA's Curiosity rover, we've learned that lakes, rivers, streams and likely oceans appearing over eons are part of the geologic history of Mars. While its epoch of active bodies of water ended over three billion years ago, the significance of their past existence is not lost on those of us who study Mars' geology.
After all, active bodies of fresh water tell us that Mars used to be habitable. This knowledge haunts us. So far, we've seen no clear evidence of life there, not even a virus. But if Mars was once habitable, wouldn't it have harbored life?
NASA is now poised to take the next step to answer this question with the launch of another rover, Perseverance.
The mission of this new rover is several-fold. Its primary and unique purpose is to collect samples that a future spacecraft can return to Earth. Every time a rover goes to Mars, it just stays there, with no way to fly back home. So we have never brought rock or soil samples back from Mars. This mission proposes to change that. According to the current concept, the process will actually take three different spacecraft: Perseverance starts by collecting the samples over a period of several years, a second mission is to land on Mars with a rocket to launch those samples into orbit around Mars, and a third would get the samples out of low Mars orbit, back into interplanetary space, and back home to Earth.
These samples will tell us more about the geologic history of Mars than anything we've currently learned, which is already a lot. Since 2012, the Curiosity rover has traveled more than a dozen miles, making observations along the way with its 10 instruments. One of those, the ChemCam laser instrument, has been zapping rocks, studying their chemical composition and telling us the nature of the large lake that once existed near Mars' equator. That instrument is commanded alternately from Los Alamos in New Mexico and the French Space Agency in Toulouse, as a partnership between Los Alamos National Laboratory and the IRAP research center. Every week, the operations change hands between the two places. Together, the ChemCam team has published nearly 100 scientific papers on its discoveries from more than 750,000 laser zaps. Other instruments study Mars' mineralogy and its weather patterns.
In addition, thanks to data from the Curiosity rover's Sample Analysis at Mars instrument, or SAM, we know that Mars does indeed have organic molecules, defined as molecules containing carbon and hydrogen, and sometimes oxygen, nitrogen, or other elements. This is exciting because organic molecules make up our own bodies — but they can also be made by non-living processes. And so the plot thickens: Do the organics we see on Mars originate from life or not?
So far, the Martian organic materials include long-chain molecules with up to 12 carbon atoms. That's more complex than we expected to find on the radiation-pummeled surface of Mars. And that's precisely why we want to gather the most interesting samples and bring them back to Earth. The robotic instruments that we send to these far-flung destinations have become more advanced over the decades, but they can't match the amazing laboratory instruments that we have at our disposal on Earth. We expect to find out much more about Mars once we get samples back from the Mars 2020 mission.
Early design work has already started on the spacecraft for the sample-return journey from Mars. In the meantime, Perseverance is going to find the samples. Once again, the rover sports a rock-zapping laser instrument, this time called SuperCam (the next-generation ChemCam). In addition to the laser shots that provide chemical compositions of the rocks, two other techniques give complementary information on their mineral content (the way the elements are bound together as molecules). Meanwhile, a microphone will listen to the snap of the laser impacts to tell the Perseverance team how hard the rocks are — another important detail both for rover operations and to interpret the geological setting. Not to mention that the microphone will give us our first-ever recordings of the Martian surface, so we can listen to the wind and any other sounds the environment might offer.
On the arm of the rover, the SHERLOC instrument also claims ChemCam heritage, specifically for its detector and electronics, which hail from Los Alamos. A fine-scale probe looking at just a few microns at a time, SHERLOC will search for organic molecules that might be signs of life.
Perseverance is now in Florida, and the team is preparing the spacecraft for launch. NASA has managed to safely continue these preparations this spring. Earth and Mars are heading toward a meeting of sorts — a close approach of some 39 million miles (63 million kilometers). It is the perfect time to send the next mission to Mars. The launch window (a number of days when the mission can start its journey between the two planets) opens on July 17. I'm not sure if I'll make it to Cape Canaveral, given the circumstances, but one way or another, I'll be anxiously watching the launch. Following that, we eagerly await Feb. 18, 2021 — the landing date. A busy time of exploration and discovery will follow, and you can be sure I'll be on pins and needles, anxiously awaiting results.
- Mars 2020: The Red Planet's next rover
- Meet 'Perseverance': NASA's Mars 2020 rover has a new name
- Photos: Ancient Mars lake could have supported life
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