ByJames Buxton, writer at
Professional Nerf Herder. Twitter: @JayDBux
James Buxton


Ridley Scott’s most recent outing finds experienced astronaut Mark Watney stranded on Mars after his crew assumes him to be dead. In order to survive, Watney is forced to use what he can in a do-or-die situation, but how much of what he accomplished was scientifically accurate?

The writer of the script, Drew Goddard, declared the movie to be “a love letter to science,” but to what extent was this true? The novel from which the movie was adapted was written by Andy Weir, who made sure to make his story as scientifically accurate as possible by spending vast amounts of time researching everything from weather conditions on Mars to the subtle details of manned space travel. However, in the transfer to the big screen, many aspects of truth may have been jettisoned in favor of pacing or maintaining the flow of the movie.


As shown in the trailer for the movie, Watney is forced to grow his own food in the Martian soil to avoid starving after his own provisions start to run thin. As far as we know, the soil he would have used is perfectly fine for growing food as long as it was supplied with enough nutrients that he could easily provide from human waste, as shown in the movie. However, while it is possible to live entirely off potatoes for over a year, they wouldn’t be particularly easy to grow.

Unlike the ground on Earth, Martian soil is very alkaline, meaning growing potatoes would be a lot harder than growing other plants such as green beans that thrive in soil with a high pH. Additionally, it’s unlikely the potatoes Watney planted would sprout due to the preservation methods used to keep them fresh for the long journey.

Overall, while it wouldn’t be impossible for someone to grow potatoes on Mars, it wouldn’t end up being nearly as successful as shown in the film. Factoring in the low light conditions would mean the potatoes that did sprout would end up being very small and would not contain much in the way of energy.


In the movie, Mars is portrayed as an eerily peaceful planet until the storms pick up and all hell breaks loose and everything is hidden behind a never-ending wall of dirt and sand. During the peaceful periods, the visuals are incredibly accurate. The landscapes are dotted with huge rocky monoliths and the occasional dust devil (a tall thin whirlwind). The shots of the planet show off the vast, rolling dunes as well as the rocky outcrops sharpened by the weather. As we’ve seen from photographs sent back from the probes sent to Mars over the years, the surface of Mars is far from consistent and Scott definitely managed to capture the planet’s constant state of flux perfectly.

Watney is regularly seen wiping dust off the solar panels. While the amount of dust buildup is slightly exaggerated, it’s been shown that electrically charged dust, commonly found across the Red Planet, is incredibly sticky and would require occasional wiping to keep the panels clear.

However, the numerous storms depicted seem to veer closer to the side of fiction than fact. In the opening scene of the film, the six astronauts are in the process of taking a few more samples before calling it a day. Everything seems to be going well and everyone is having a good time when suddenly, Kate Mara’s character, Beth Johansen, informs the crew that there’s a violent storm inbound. In reality, Martian storms such as this one are a planet-wide event that can have wind speeds of over 150 kilometers per hour. The crew would have had days to prepare for the storm and would have probably remained inside throughout the day to avoid getting caught up in it.

However, with such a thin atmosphere, even winds of that strength are unlikely to topple a rocket or throw a human being into the air. In reality, the wind would probably end up being about as strong as a mere 15 kilometer per hour wind on Earth.


The ship that the crew used to return to Earth, the Hermes, is equipped with a huge gym to keep fit during the long haul journey. The need to keep active in space is very important and is also used today aboard the ISS. Due to the lack of real gravity in space, muscles degrade and weaken very quickly. Even though artificial gravity is maintained aboard certain sections of the ship, it’s unlikely to be enough to keep healthy. According to NASA, all astronauts are expected to spend two hours of every day exercising during long periods in space.

For Mark Watney back on Mars, the need for exercise would be less due to the planet’s gravity. However, spending such a huge length of time in weakened gravity would have serious negative effects once he returned to Earth. He would likely suffer from weakened bones and muscles for several years after returning and living with barely any source of protein for a year and a half certainly won’t help.

Unfortunately for Mark and the rest of the crew, though, the surface of Mars is not an easy place to stay healthy, even within the confines of a specially designed base. Due to Mars’ extremely weak magnetic field, the planet provides little to no protection from solar radiation. A small, overground base like the one seen in the movie would also fail to protect the humans inside, resulting in most if not all of the occupants slowly dying of cancer. One idea to avoid this posed by NASA is to build underground bases on the planet beforehand to shield the astronauts from the radiation upon arrival.

The process would be even worse for the crew of The Hermes, who would be completely unprotected from the cosmic rays during their stint in interplanetary space. Unless NASA can come up with a cheap, light way of protecting humans from radiation in space during the next twenty years, a trip to mars is only going to end in tragedy.

Technology on Mars

The extensive use of solar panels on Mars is likely to be the way we actually keep a base powered when we visit the Red Planet. Virtually all of the probes and rovers currently exploring Mars use solar panels to keep themselves chugging along.

Half way through the film, disaster strikes as an airlock malfunction causes Watney’s home to rip open, killing all his crops and draining the base of oxygen. At the same time, Watney’s spacesuit is pierced and he’s left open to the elements. Acting quickly, Watney manages to solve both issues with duct tape. After patching up his helmet, Watney returns to normal health very quickly, when in reality anything more than a minute exposed to the Martian atmosphere would be enough to kill him. Before the lack of oxygen gets to him, the low pressure of Mars’ atmosphere would be enough to rupture his skin and cause his blood to boil. But before that, he would probably freeze to death. Mars’ average temperature is a brisk -66°F, enough to kill anyone who isn’t suitably protected.

However, his use of duct tape to seal his helmet was not quite as ridiculous as it may sound. Duct tape was originally designed to be a quick airtight seal for air duct terminals, making it the perfect tool for Watney’s situation.

To seal the broken airlock, Watney uses a plastic sheet held in place with tape. While such a material has not yet been perfected, NASA have stated that they are planning on testing a new inflatable module of the ISS sometime in the near future. While it’s likely such a material would be enough to hold the air in, its ability to withstand the bombardment of rocks seen in the movie is still debatable.

Technology in Space

The Hermes is one cool looking ship. Designed for long journeys, it features living quarters fitted with artificial gravity and a powerful ion engine with roots in both science and science fiction.

For starters, the artificial gravity is pretty much spot on. By making certain sections of the ship spin at a fixed rate, centripetal force is generated. What this does is pull everything to the edge, much like those spinning rotor rides at carnivals but on a much larger scale. This gives the impression of gravity in the spinning compartments.

The engine however is slightly less realistic. While ion engines have been tried and tested in the past, the amount of power needed to carry such a large ship such a huge distance would be astronomical. The majority of the ship would have to be taken up by energy storage, reducing the speed due to the excess mass. While technology can only improve in the future, the chances of perfecting ion technology by 2035, the setting of The Martian, are quite slim.

Overall, The Martian manages to stick pretty close to the truth, usually only veering into fiction to supplement the story.

The Martian is in theatres now and stars Matt Damon and Jessica Chastain.

Sources: Business Insider, io9


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