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Life on Mars? Meet the new rover built to give us the answer

Artist's illustration of NASA's Mars 2020 rover Perseverance exploring the Red Planet. Perseverance's three-week launch window opens on July 17, 2020.
Artist's illustration of NASA's Mars 2020 rover Perseverance exploring the Red Planet. Perseverance's three-week launch window opens on July 17, 2020.
(Image: © NASA/JPL-Caltech)

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.

Related: NASA's Mars 2020 rover Perseverance in pictures

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? 

Related: The search for life on Mars (a photo timeline)

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. 

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  • Geomartian

    Can the new rover strangle somebody?

    It doesn’t have a real microscope and no direct chemical (growth media) tests for life. Houston is not even trying that hard to make sure that life remains only a scientific possibility buried in the ancient past. Life on Mars would be planetary heresy for Houston’s “nothing happening here just move along” planetary geology.

    Science advances with each funeral and the new rover could go berserk in Houston and advance science a great deal.
    Reply
  • Dandere
    Geomartian said:
    Can the new rover strangle somebody?

    It doesn’t have a real microscope and no direct chemical (growth media) tests for life. Houston is not even trying that hard to make sure that life remains only a scientific possibility buried in the ancient past. Life on Mars would be planetary heresy for Houston’s “nothing happening here just move along” planetary geology.

    Science advances with each funeral and the new rover could go berserk in Houston and advance science a great deal.
    I'm all for liquidating academicians who have been in their field too long and are polluting it with outsize influence and opinions they formed in the 1970s, but I have bad news: There's no life on Mars. Absolutely zero evidence there ever was. Normally I wouldn't be against further investigation, even at the cost of the tens of millions of dollars these rover experiments run, but I fear that unfounded claims that the possibility of life on Mars could exist will be used as cause to justify the delay of colonization efforts. Colonization efforts that I intend to join as an planetary geologist.
    Reply
  • Geomartian
    Dandere said:
    I'm all for liquidating academicians who have been in their field too long and are polluting it with outsize influence and opinions they formed in the 1970s, ... Colonization efforts that I intend to join as an planetary geologist.

    Mars’ planetary geology is currently a mess of self contradictory secret geology maintained by Houston’s oil men. The good part (for you) is that the geology of Mars is a lot more active than described in Houston’s fictional narrative. There is some on-going volcanic activity on parts of Mars. You might find lava tubes that are above freezing all the time.

    Radioisotope thermoelectric generator RTG’s are not like teddy bears so a nice warm cave makes life a lot simpler.

    The heat from the planetary core is largely irrelevant as seen by the amount of melt generated by an interstellar asteroid impact on/through Mars’ northern hemisphere less than 200 mya (Martian meteorite dating).

    Mars’ geology might have a lot more ore bodies than current orthodoxy could explain. Ore bodies can be generated on Mars and Earth by interstellar asteroids. Instant volcano (just add interstellar asteroid) can provide the heat for concentrating ore bodies in wet or water saturated Martian strata. Without global tectonics ore bodies on Mars don’t get subducted (but can be buried by sediments). Once they are created Martian ore bodies tend to stick around.

    Four billion years of interstellar asteroid impacts along with the presence of water should have created a lot of ore bodies on Mars.

    On Mars a gravimeter is your best friend when looking for ore bodies.

    An encyclopedic knowledge of explosives that could be manufactured with Martian materials would make you worth your weight in Oreos (Martian medium of exchange).
    Reply
  • dfjchem721
    Dandere said:
    I'm all for liquidating academicians who have been in their field too long and are polluting it with outsize influence and opinions they formed in the 1970s, but I have bad news: There's no life on Mars. Absolutely zero evidence there ever was. Normally I wouldn't be against further investigation, even at the cost of the tens of millions of dollars these rover experiments run, but I fear that unfounded claims that the possibility of life on Mars could exist will be used as cause to justify the delay of colonization efforts. Colonization efforts that I intend to join as an planetary geologist.

    The current absence for evidence of life on Mars provides no proof that it never existed. Indeed, all evidence from surface probes indicates a reasonable probability that it did arise, and current conditions could still allow for sub-surface life forms to persist. Since life clearly arose by abiogensis on earth right next door to Mars, it is reasonable for most real scientists today to assume (which they do) that it could have arisen on Mars in much the same fashion, particularly since the chemistry of the two planets is very similar.

    It is impossible for the well-informed to believe that all those old (and some new) scientists at NASA (and JPL, etc.) are a bunch of idiots to be looking for evidence of life on Mars. Those who think otherwise might use this concept to review their own perspective. Belief in a false premise could be professionally fatal.

    And all the old scientists, many well before the 1970s, provided us with most of the knowledge that we currently work with to discover new things everywhere, on earth, and "out there". They were not a bunch of idiots either. If they were, space exploration would be a long dead concept. It would seem to most rational people that appreciation, rather than contempt, is their due.

    Anyone trying to be a scientist or engineer of some kind would be well advised to remember the ideas, theories and concepts of all those real scientists who came before today. Again, they laid the foundation on which almost all existing science is conducted.

    It is important to point out that in the field of science, there is nothing worse than being wrong. Ignoring the science of the past is a great start to being wrong, and many people are clearly well on their way!
    Reply
  • Wally Mayo
    Firstly - wonderful! - To hopefully finally get some Mars rocks back for analysis!
    Secondly, to date, more than 20 Martian meteorites have been recovered on earth. These Martian rocks were blasted away from the grip of Mars' gravity many years ago as asteroids and comets crashed upon that planet's surface. Of all the Martian rocks ejected into outer space, 7.5 percent eventually find their way to Earth. In 4 billion years about 4 billion tons of Martian material has been deposited on Earth. More interestingly, during the 3.8+ billion-year-history of life on Earth at least a hundred million tons of Earth material has landed on Mars. Attached to these hundred million tons of Earth material are at least several million pounds of Earth-life remains. If NASA searches long and hard enough, it should find evidence for at least some small amount of life remnants on Mars. Such a discovery will grab headlines for sure, but further study will reveal the source of those remains (likely remnants from earth).
    Thirdly, " arisen in a...similar fashion ?" The chemistry is NOT so similar. Mars has 40x more sulphur in its topsoil. (So much for Matt Damon's little happy garden in the movie The Martian).
    Next, despite the excitement, the subterranean “lake” below the surface likely consists of a large volume of liquid water mixed with copious amounts of rock, salt, and perchlorates. Science (July 25, 2018): eaar7268, doi:10.1126/science.aar7268 ] Such chemistry is NOT conducive to life. The math challenge has really gotten pretty severe on even getting life to start on earth, much less such a hostile planet.
    BTW, these are real scientists that I have cited. And, BTW, "in the field of science, nothing is worse than being wrong?" Even Einstein was at times wrong, and admitted it when he knew better. It's how we learn, and eliminate (sometimes slowly) error.
    But, I agree with your scowl on Dandere's lack of interest in the search on Mars. And, concerning easy colonization, he needs to read the excellent assessment here on this site - https://forums.space.com/threads/mars-colonies-are-a-fantasy.29123/ -- first entry.
    Reply
  • dfjchem721
    Actually, perchlorate could stimulate the development and evolution of life on Mars, as it has on earth. Perchlorate reductase and chlorite dismutase are used by over 40 different and diverse microorganisms, all thriving by reduction of perchlorate. The reactions produce chloride anions and O2. Some subterranean bacterial species consume pyrite and emit sulfur as waste. The chemistry of life can be remarkably variable. While temperature and pH must be limiting in an aqueous milieu, the numerous constraints on chemical compositions and conditions are not well established. The presence of perchlorate and sulfur are not good examples for projecting a negative probability for life on Mars.

    Various compounds found on Mars could suggest that life might not form there. However, this assumes they are present in all potential eco-systems, and toxic to abiogenesis and continuation of life, not just toxic to certain forms, as the perchlorate and sulfur examples with life on earth clearly demonstrate. Mars has a rather diverse geology, just like earth. It is impossible to say at this time whether conditions were ever permissible for life to arise and persist on Mars, particularly as such conditions are presently unknown. Grand proclamations based on limited data should be suspect until proven otherwise. Nothing worse than being wrong......
    Reply
  • Wally Mayo
    Water, water. Important, but it's not totally assured that Mars has a "stable" subterranean body of liquid water on Mars. As Jeffrey Plaut, a MARSIS principal investigator at the Jet Propulsion Laboratory who was not an author on the paper, stated in an interview, “I would say the interpretation is plausible, but it’s not quite a slam dunk yet. .

    Part of the MASUS (Mars Advanced Radar for Subsurface and Ionospheric Sounding) team (twenty-two planetary astronomers from research institutions in Italy) who form part of the MARSIS mission, concluded that the likely liquid water layer was located right under a 1.5-kilometer-thickness of ice, which is the thickest part of the south polar ice cap. The pressure from 1.5 kilometers of ice raises the temperature of the likely liquid water layer to -68°Celsius (-90°Fahrenheit). For water to remain liquid at this very low temperature, the water must be saturated with perchlorate salts. This perchlorate saturation rules out any possibility of life surviving in the layer. As geophysicist David Stillman of Southwest Research Institute in Boulder, Colorado, stated in an interview, “If Martian life is like earth life, this is too cold and too salty. " Science, first release (July 25, 2018), doi:10.1126/science.aau8871]
    Yes, there is plenty of types of metabolyses with pretty amazing extremophiles on earth (esp. ocean depths). But, just because we find them today, does not mean it originated that way, especially with extreme thermophiles. So much of their metabolism is spent repairing thermal damage. OOL search seems better looking elsewhere.

    Anyway, the determination that the radar bright subterranean layer must be a saturated perchlorate brine led the team (of 22 planetary astronomers) to draw two different possible conclusions about the nature of the layer. In their work they mentioned, “The brine could be mixed with basal soils to form a sludge or could lie on top of the basal material to form localized brine pools.” Science, Reports, first release (July 25, 2018): 1–9, doi:10.1126/science.aar7268]
    I'm just saying, the MARSIS discovery is not a big freshwater lake, as some internet reports implied. Nor does it seem to me to be a layer that is a particularly possible habitat for life. However, I must add, if indeed the layer is saturated with perchlorate salts, it is highly probable that it is a site with at least a small quantity of stable liquid water. I try not to totally close the door on possibilities, esp. with lots of unknowns.

    I never meant wrong in science is good. But, it may not in the end be the absolute worst, if it reveals something new, and we don't cling to the wrong. I should've have cast it better in the sense of wrongs as failures. As in, Edison's "Now we know another way it doesn't work." I say this to my science students when they get something wrong. I then say, okay what have we learned from this!! "Why were we wrong?" (Yes, a better situation is usually, getting it right the first time).
    Reply
  • Geomartian
    The bright radar reflection would indicate liquid water. Liquid water has a very high dielectric constant, while ice does not. As far as salts are concerned what was the dielectric loss for these measurements? An EM wave like radar creates an evanescent wave on the other side of the ice/water dielectric interface. If that evanescent wave encounters a high loss dielectric the reflection can be greatly reduced. Water which is as salty as they describe is a high loss dielectric producing a reduced to negligible reflection.

    Nasa’s temperature analysis is bogus since Mars is currently experiencing some low level of volcanic activity. Houston’s crocodile tears about the death of Mars billions of years ago covers up heating of the Northern Hemisphere by an interstellar asteroid impact about 200 mya. Thermal diffusion from the impact could have heated the interior of Mars so that liquid water could exist near the surface without it being toxically salty.

    Perchlorates were blamed for the false biological positives of the Viking landers so this could be an example of reinforcing a fiction by endless repetition.

    Nasa has a tendency to send crippled missions (no microscopes and no more biological tests) to Mars after the Vikings.

    I doubt you could drink the Martian water but I also know with certainty that Mars is geologically warmer than Nasa will admit.

    There is bad science and then there is corrupt science. When someone’s economic agenda conflicts with science, science usually loses.
    Reply
  • Wally Mayo
    You've got some reasonable points regarding temperature. Also, lack of sensors in missions. And, especially your last sentence!
    Still, color me skeptical on subterranean life, even on outer planet moons (deep water below the crust, etc.). But, that is another discussion.
    Reply