How Accurate Is The Martian? 9 Things The Movie Got Right And Wrong

Matt Damon stars as Mark Watney in The Martian. 20th Century Fox.

"The Martian" is hitting cinemas right about now, and already it is being heralded as one of the most scientifically accurate sci-fi films of all time. We’ve seen the movie, and we’ve got to say, it’s amazing how far we’ve come since "Armageddon" (shudder). NASA has been so impressed, they've been using the movie as a marketing campaign for their own, actual manned missions to Mars in the 2030s.

Based on the book of the same name by Andy Weir, itself praised for its accuracy, director Ridley Scott asked NASA to check the film and ensure everything in it was correct – or as correct as can be. But just how did they do? Here we pick through the science in the movie, with the help of a few experts, to see if "The Martian" is deserving of its accolades.

Be warned, though, there are some spoilers in this post. So if you haven’t read the book or seen the movie yet, continue at your own peril.

The dust storm

Let’s get the big one out of the way nice and early: The dust storm that sets everything in motion at the start of the movie is not accurate. Although Mars does get dust storms, the atmospheric pressure is so low that the wind is negligible, although the dust itself can be harmful.

This is probably the least scientific part of the movie. But hey, at least it's out of the way nice and early. 20th Century Fox.

“Dust storms certainly do occur on Mars, they get winds in excess of 100 mph (160 km/h),” Dave Lavery, Program Executive for Solar System Exploration at NASA headquarters and a consultant for the film, told IFLScience. “But a 100 mph wind on Mars, because the atmosphere is so thin, has the same inertia and dynamic pressure down at the surface as about an 11 mph (18 km/h) wind on Earth. It’s not going to have the sort of energy to move large objects the way that is portrayed in the book and the film.”

To be fair, Andy Weir readily admits the dust storm was used simply to move the plot along and leave Mark Watney stranded on Mars. But hey, we’re not letting him get off scot-free.

Fact or fiction? Fiction

Orbital dynamics

Perhaps one of the best factual aspects of the film is the accuracy of the travel time between Earth and Mars. While some science fiction films have the characters whizzing from point to point, "The Martian" reveals the brutal reality of spaceflight: It would take about eight months to get to or from Mars with current technology.

“This is not just a story, the author has done real computations,” Rudi Schmidt, ESA Project Manager for Mars Express and also a consultant on the film, told IFLScience.

Fact or fiction? Fact

Future manned Mars missions will use a constantly orbiting spacecraft akin to Hermes (shown). 20th Century Fox.

Martian soil

In the movie, after becoming stranded on the surface, Watney resorts to using a combination of his own excrement, water, and Martian soil to grow potatoes. But would Martian soil actually be of any use? Isn’t it sterile and dead?

“In terms of basic mineral content and chemical content, yes it would be possible to grow plants in Martian soil,” said Lavery. “We actually have experiments going on right now using simulated Mars soil, and it indicates that’s a very realistic idea.”

Fact or fiction? Fact

Mmm, delicious. 20th Century Fox.

Radiation

Spending any prolonged amount of time in space, we’re talking months or years, runs an increased risk of developing a radiation-related sickness, such as cancer. Modern astronauts stay in the safe confines of Earth’s magnetosphere, while the Apollo astronauts spent just a few days at the Moon.

But on Mars, each Ares crew was spending up to a month on the surface in the movie. It’s likely that the habitat as depicted in the film might be a bit different on a real future Mars mission; it might be necessary to partly submerge it in the ground, providing natural protection from radiation.

“The reality is I think people will go underground, to protect against radiation from the Sun,” said Schmidt. “The structures will be on the surface, but machines will be used to protect them with Martian sand.”

And what about Watney, who spends more than a year on the surface, often with nothing more than his spacesuit for protection? Well, although the radiation levels on Mars are less than expected, it’s possible he would have considerably increased his risk of cancer, although he was unlikely to have experienced any immediate effects during his stay. We’ll call this one a tie.

Fact or fiction? Tie

An actual Martian habitat might need to be submerged to keep its occupants safe from radiation. 20th Century Fox.

Taking off from Mars

To leave the Red Planet, each Ares crew uses a Mars Ascent Vehicle (MAV). In the book, it’s explained how this plucks methane out of the Martian atmosphere to create fuel. The rocket then accelerates to an orbital velocity that allows it to rendezvous and dock with the Hermes spacecraft, which then brings the astronauts back to Earth. Feasible?

At the moment, no. NASA readily admits this is one of the biggest obstacles to future Mars missions. They just simply don’t know the logistics of taking off from Mars, and all the unknowns that brings with it. Just think of taking off from Earth; although there are hundreds of launches every year, a few now and then end in failure. Mars has 30% of Earth’s gravity and a sizable atmosphere, so it’s not going to be easy. “Taking off from Mars is one of the biggest problems we’re working on right now,” said Lavery. 

To find out how it might be done, NASA is planning a sample return mission in the 2020s. The tentative plan at the moment is for the currently unnamed 2020 Mars rover to collect samples and leave them on the surface, which will be picked up by a later lander and launched back to Earth. “That would form our basis for the same technology and techniques for a human mission,” said Lavery.

So this one is fiction for now – but only because we don’t know how to do it yet.

Fact or fiction? Fiction

Leaving the surface of Mars is a big unknown at the moment. 20th Century Fox.

Tornadoes on Mars

In the movie, you might be surprised to see giant tornadoes seemingly tearing up from the surface into the sky. If the Martian atmosphere is so thin, can it really form these? Why yes. Yes it can. Sort of.

Mars has tornadoes in the form of dust devils, whirlwinds that whip up debris on the surface. They can be up to half a mile tall, although still relatively wispy, so they might not look quite as dramatic as in the movie. But they are impressive nonetheless, and in 2005 the Spirit rover actually managed to capture one in action on the surface.

Fact or fiction? Fact

Communicating with Earth

When the communications system at Watney’s habitat is destroyed in the (questionable) storm, he has no way to communicate with Earth until he goes to pilfer Pathfinder and Sojourner, the lander and rover that touched down on Mars in 1997. They went silent on the surface after just a few months, but could Watney really have repurposed them to make contact with Earth again?

“Theoretically, it would absolutely be possible,” said Lavery, and he should know, as he worked on the Pathfinder mission. “The spacecraft has been sitting up there since 1997, and it stopped operating because the batteries finally drained and gave out. But if you replaced them and repowered it, everything else should still be functioning.”

Houston, we have a solution.

Fact or fiction? Fact

It's true, Watney would have been able to talk to Earth. 20th Century Fox.

Gravity on Mars

Watney moves in an Earth-like manner on Mars, but in reality the Red Planet has about 30% of the gravity our own planet has, meaning movement would be a little different. NASA envisages that the most efficient way to walk on Mars will be a gait somewhere between a shuffle and a hop. We can appreciate why it wasn’t portrayed this way in the movie, but hey, a win’s a win for fiction.

Fact or fiction? Fiction

The habitat

Pretty accurate. The idea of using an inflatable habitat, which is what is used in "The Martian," is one that is being seriously considered. Indeed, soon an inflatable Bigelow Aerospace module will be attached to the ISS, and a descendent of that could be used on Mars. Whether an inflatable habitat could cope with having a flat floor on Mars is another question, as inflatable things tend to want to form a ball, and in the thin Martian atmosphere, the pressure on a habitat with an Earth-like environment inside might be too much. But it’s possible.

Fact or fiction? Fact

Inflatable technology will be key to the future of manned space exploration. 20th Century Fox.

Conclusion

Overall, we score that at five for fact, three for fiction and one tie. And we’ve only brushed the surface – there were many other things the film got right, including the aesthetics on Mars, the spacesuits, the use of solar panels, the Hermes spacecraft (apart from maybe its rotation speed), the life support systems, and so on. On the other hand, there's not much else it got wrong, aside from maybe the speed at which the astronauts go from the Hermes spacecraft into space without proper preparation.

Sure, we’ve picked out a few grievances, but they are minor quibbles. And compared to other movies (*cough* "Armageddon" *cough*), they are trivial. We'd have to say "The Martian" is deserving of its scientific plaudits.

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