The Potential for Life and Exploration on Mars
This summer, a group of scientists found groundbreaking evidence of recently flowing liquid water on Mars. Since this was confirmed by NASA, the resulting frenzy over this discovery has many people wondering what exactly the big deal is. To add some perspective, one should keep in mind the unofficial motto of astrobiologists: “Follow the water.” Framed by this motto, the discovery of water on Mars has implications for life and future human exploration.
The confirmation of liquid water on Mars is not suggesting that there are flowing rivers and standing lakes. Rather, the water is present in features called Recurring Slope Lineae (RSL) — long dark markings that appear along the insides of craters and down the sides of mountains during the Martian spring and summer. Inside these RSL, scientists found salts saturated with water. As such, these RSL can be likened to thin layers of damp soil.
The discovery of water on Mars has implications for extant life and future human exploration.
Despite the enormous astrobiological implications of liquid water on Mars, some are questioning whether the RSL are a promising place to look for life. The reason for this doubt is the same reason why the liquid water even exists: it is incredibly salty. Dr. Christopher P. McKay, an astrobiologists at NASA’s Ames Research Center, likens the liquid water on Mars to the famously salty, always-liquid Don Juan pond in Antarctica: “You fly over it, and it looks like a beautiful swimming pool,” Dr. McKay says, “But the water has got nothing.”
Some scientists are more optimistic. Dr. David E. Stillman suggests: “If it was too salty, they would be flowing year round. We might be in that Goldilocks zone.” It is possible that a small niche of life could live in the briny water present on Mars. Microbial life is famous for its ability to survive in extreme environments.
Despite the enormity of the discovery of liquid water in the RSL on Mars, these areas are treated as restricted zones for the current robotic explorers on Mars. The reason for this is simple: they haven’t been sterilized. The rovers sent to Mars don’t get hot enough on the trip to kill all of the microbes possibly living on them. Scientists want to avoid potentially contaminating the Martian environment with organisms from Earth. As John Grunsfield puts it “NASA has to be careful they don’t send a mission to Mars to detect Martian life and instead ‘find’ what is actually the life from Earth they may have transported there themselves.”
The discovery of liquid water on Mars has large implications for future human exploration as well. Doug McCuistion, the former head of NASA’s Mars program describes the finding as “game-changing” for future Mars exploration. One of the biggest obstacles in human space travel is producing enough oxygen and water to sustain the crew. Water on Mars means a significantly lighter load for potential spacecraft. Although manned missions are not expected to be carried out in the near future, NASA’s first science goal for missions to Mars — determining if life ever arose on Mars — is greatly helped by the discovery of liquid water. If all goes well, humankind may step foot on Mars sooner than expected.