Is The Martian Scientifically Accurate?

In Ridley Scott’s “The Martian,” the crew of the Ares III head to Mars for an expedition. Just as their ascent vehicle lands, a severe dust storm topples it, causing the crew to scramble toward their orbiting vessel. However, one crew member, Mark Watney (Matt Damon) gets hit by debris and is left behind, presumed dead. What ensues is Mark’s tireless attempts to establish communication with NASA, while trying to science the heck out of this situation to stay alive. A smart balance is struck between remaining scientifically authentic and making these high-concept ideas accessible, as Mark’s perseverance only bears fruit because of his knowledge as a botanist and mechanical engineer. But how scientifically accurate is “The Martian?”

To answer this question quickly: it is pretty accurate. NASA’s Jet Propulsion Laboratory (JPL) helped flesh out the scientific details of the story, with real-life Mars exploration data being used to map the onscreen planet’s terrain and design compatible vehicles. The Mars Pathfinder, which Mark uses to survive and communicate, was built and designed by JPL to grant legitimacy to the technical aspects of this survival story. Even some of the devices used here are real, including the RTG (which works like a battery) Mark uses to stay warm, as similar power systems are still used for Mars-related missions.

That said, there are plenty of inaccuracies here and there. This does not necessarily detract from the experience, as the “fiction” part of science-fiction also needs to do some heavy lifting to elevate the most grounded premises. “The Martian” succeeds in doing so, as it re-frames a perseverance story into one that dares to defy expectations. There is humor mixed in with pathos, and undying hope laces Mark’s long, arduous journey back to Earth. On that note, let’s look at what the film gets right and wrong about the science involved from start to finish.

The dust storm is the catalyst for the events of the film, but is it a natural event that can occur on Mars? Well, the red planet’s atmosphere is much thinner than the Earth’s, which means that a strong wind (like one at 100 mph) would feel much less potent (around 10-11 mph). If the strongest gust of wind on Mars is not powerful enough to knock down a human being, it cannot topple a heavy Mars Ascent Vehicle (MAV). However, the dust storm is a great fictional catalyst that triggers Mark’s survival story in space.

Next, Mark synthesizes drinkable water from rocket fuel by dissociating (splitting the molecules to form other states of matter) it into nitrogen and hydrogen. He takes the hydrogen and burns it using the oxygen inside the cabin to make water. This is not inaccurate, as this will work 100%, but a person stranded on Mars has a better, quicker way to synthesize water. You see, water is abundant on Mars in the form of ice and permafrost, so the planet’s soil is a rich reservoir that can be used quickly for this purpose. But of course, dissociating rocket fuel is a pretty cool thing to do (even though one misstep can ruin all the progress).

Now, let’s talk about gravity. Mars has one-third of the gravity we experience on Earth, which makes humans and objects weigh much less than what they do back on Earth. For example, if a rock weighs 100 kilograms on Earth, it will weigh around 33 kilograms (and hence feel much lighter) on Mars. In “The Martian,” this is not factored in at all, as all the astronauts seem to be exhausted after climbing ladders or walking around in their astronaut gear. Although the gear is pretty heavy on Earth, it shouldn’t encumber movement on Mars, as lesser gravity will warrant lesser exertion.

When all efforts to rescue Mark seem borderline impossible, JPL astrodynamicist Rich Purnell (Donald Glover) proposes a risky, ballsy plan. He suggests that the re-supply launcher should rendezvous with the original spacecraft, The Hermes (where Mark’s crew are at that moment), which will then use Earth’s gravity to slingshot back to Mars. Even though several things go horribly wrong, The Hermes crew succeeds in rescuing Mark after he punctures his pressure suit to propel himself toward Commander Lewis (Jessica Chastain). This makes for a thrilling, high-stakes cinematic climax, but is it practically probable at all?

Yes, it is! In fact, this is a real-life method that is used to accelerate the speed of a spacecraft or redirect its path to save propellant or reduce costs. Known as a gravity assist, this maneuver uses relative movement (trajectory of a planet’s orbit around the sun) and planetary gravity to simulate a slingshot effect like the one shown in the film. Although this method was first used during a Soviet probe of Luna 3, Michael Minovitch (who worked as a trajectory analyst at JPL) developed a gravity assist technique in 1961, which helped increase spacecraft velocity down the line. This technology eventually became the foundation for the groundbreaking Voyager space missions.

Smaller details about “The Martian,” like the time taken to travel to Mars — which is close to 8 months — are also accurate. Even the science behind Mark being able to grow potatoes on Martian soil is scientifically sound, as it is possible to nurture vegetation with the planet’s soil, but that also depends on the quality of the chemical and mineral content. Let’s just assume that Mark got lucky in some aspects, but every other survival milestone he achieves is completely to his credit. The rest can simply be chalked up to the enduring power of cinema.