12 October 2015

Flowing water on Mars: What that means for ‘The Martian’

Posted by lcooper

Fictional astronaut Mark Watney (Matt Damon), stranded on Mars in the film “The Martian,” fights to stay alive despite the planet’s hostile conditions, until a hoped-for rescue mission can arrive. Credit: Twentieth Century Fox

Fictional astronaut Mark Watney (Matt Damon), stranded on Mars in the film “The Martian,” fights to stay alive despite the planet’s hostile conditions, until a hoped-for rescue mission can arrive.
Credit: Twentieth Century Fox

If the fictional astronaut’s journey were real, could he have taken advantage of the newly discovered flowing water?

By JoAnna Wendel

Faced with a sudden and urgent need for food, Mark Watney did what any astronaut stranded on Mars would do: he filled his living quarters with Martian soil, fertilized it with his own waste, built a contraption to chemically create water, and grew some potatoes.

Watney is the fictional astronaut created in the mind of novelist Andy Weir, whose best-selling book “The Martian” was just adapted into a Ridley Scott science fiction thriller. Botanist-turned-astronaut Watney, stranded after a storm forces the rest of his mission crew to evacuate the planet, is forced to rely on his own wit and expertise to survive a hostile world and seek a way home. He is left with little water and a quickly diminishing supply of food (not to mention that the selections of music left behind by his crewmates aren’t to his taste).

So far, the movie has received resoundingly good reviews, especially from the planetary scientists who study Mars. Even its scientific inaccuracies—the storm at the beginning of the story that sets the entire plot in motion wouldn’t be possible in Mars’s thin atmosphere—doesn’t seem to diminish positive reactions among scientists, according to Discovery News.

The movie “gives me a wonderful opportunity to tell people what Mars is really like,” said Jim Green, Director of the Planetary Sciences Division at NASA. “The more science we do and the more we learn about the planet and its environment, really the easier it is for us to go to the places where we can find life.”

Watery revelations

In a recent Reddit “Ask Me Anything” thread, strangers from all over the world asked Weir their most pressing questions about the book and movie. The author said that if he could, he might go back and add a line or two about the water that NASA’s Curiosity rover found locked within Martian soil.

Shortly after the novel came out in 2014, scientists analyzing data from the Curiosity rover discovered that Martian soil actually held about 2 percent water. While this is still about 10 times less than that of Earth, it could still bode well for future human-piloted Mars missions. According to Space.com, Laurie Leshin, President of Worcester Polytechnic Institute in Worcester, Massachusetts, and lead author on the paper that reported Curiosity’s watery revelations, said at the time that astronauts with the right tools could extract roughly 2 pints (1 liter) of water of out of every cubic foot of Martian dirt.

Last week, NASA scientists announced that they had found evidence for flowing water on Mars’s surface during warm periods. A Mars-orbiting spacecraft that was observing transient streaks on the Martian surface—called reoccurring slope lineae (RSL)—detected chemical signatures of hydrated salts, mostly of the chemical ion perchlorate, which indicated the presence of liquid water near the surface. With that and the higher-than-thought water content of Mars’s soils, perhaps Weir’s wise-cracking hero wouldn’t have had to create so much water from scratch, said Green. Even Ridley Scott, the director of the new movie, told The New York Times that in light of NASA’s most recent discovery about liquid water appearing seasonally on the Red Planet today, he might have changed aspects of the story.

But even if this liquid water had appeared in the novel or the movie, could Mark Watney have accessed it?

Probably not, said Green. The RSL found in Acadalia Planitia, where most of the film’s story plays out, lie a distant 400 kilometers (250 miles) north of Watney’s mission base. Furthermore, these watery features only appear during the late spring and summer on Mars, and Watney and his fellow astronauts landed during the “dead of winter,” said Green. By the time Martian summer rolled around a few hundred Martian-days later, Watney was on his way out of Acadalia Planitia, travelling east towards Schiaparelli crater.

However, Green said that nothing about the movie should change (as of this writing, he’d seen it five times). Even without the newest facts about Mars, “’The Martian’ will endure,” Green continued. “Classic science fiction in its own right is something we always will read and enjoy.”


Even before Curiosity found water in Mars’s soil, NASA’s Phoenix Lander in 2008 found that near its poles, Mars’s soil has a pH resembling that of the average vegetable garden on Earth. The lander also found key nutrients in the soil that would aid any budding potato—magnesium, sodium, potassium and chloride ions. Since then, scientists have even found nitrogen in the soil.We’re finding things in the soils that would significantly increase our ability to grow things,” Green said.

Even with its life-giving nutrients, however, Mars soil also contains substances, like perchlorates and other toxic salts, which make it hostile to living things.

Last year, a team of scientists in the Netherlands set out to investigate if plants could grow in Martian-like soil. They acquired simulated Martian soil manufactured by NASA and planted several crops, including wheat, tomatoes and carrots. Compared with plants grown in Earth soil and simulated Moon soil, the Mars plants did relatively well, in some cases even producing flowers and surviving to the end of the 50-day experiment.

Despite this new hint that Martian soil might have what it takes to help sustain a stranded astronaut, the planet’s thin atmosphere, cold conditions and distance from the Sun would still require Mark Watney-level ingenuity to actually coax plants into setting down roots.

—JoAnna Wendel is a staff writer for EOS.