Could you run a marathon on Mars? And also — would you want to?
NASA’s Perseverance rover just completed an off-Earth marathon: It has now traveled more than 26.2 miles (42.2 kilometers) across the Martian landscape after landing in February 2021, according to the mission team. The only other rover to complete a marathon on the Red Planet is Opportunity, which took over 11 years to traverse the distance. But as NASA looks toward potentially landing humans on the Red Planet some day, it makes me wonder: What would it be like to complete a marathon on Mars … on foot?
Here on Earth, I have run a few marathons — in Philadelphia, New Jersey, and Florida, I’ve managed to wheeze, sweat, and drag my feet over the finish line. You’ll never catch me on the leaderboard, but I’ve felt all the unique stings and challenges of the race. From the unexpected charley horses to the mental hurdles you overcome, no marathon is easy. But on Mars? We’re not comparing humans to rovers, and Perseverance has spent these past five-plue years not just traveling but exploring and conducting scientific investigations. But if we imagine a future where we successfully send humans to Mars, let’s explore what it might really be like to travel 26.2 miles on foot across the Red Planet.
Mars is brutal
For starters, Mars is cold. And while completing a marathon is difficult at any temperature, the cold presents unique challenges, like aggravating breathing troubles and causing your joints to stiffen. The freezing temperatures that you’d find on Mars could certainly pose a challenge for joints and muscles, and depending on how cold it is, sweating due to physical exertion in extreme cold could even increase your risk of hypothermia.
Mars’ atmosphere is very thin, so heat from the sun escapes very quickly on the Red Planet. And because Mars is millions of miles farther from the sun than Earth, temperatures on the surface can plummet to as low as minus 225 degrees Fahrenheit (minus 153 degrees Celsius).
That’s not to say it’s always that cold. If you stood exactly on Mars’ equator at noon, you could feel soothing, springtime temperatures of up to 70 degrees F (20 degrees C), according to NASA. But generally speaking, the surface of Mars is quite cold.
A heavy weight
Mars’ air isn’t breathable, either; it’s about 95% carbon dioxide. So you’d have to walk around in a spacesuit, meaning you’d never feel those spring-like temperatures directly anyhow. But you might warm up a bit, carrying the weight of that suit.
While the lower gravity on Mars would help out a bit, current spacesuits and their accompanying life support backpacks weigh well over 200 pounds (90 kilograms), and on Mars they could still weigh close to or over 100 pounds (45 kg), it has been reported. We don’t yet know how future astronaut suits will be built or how much they might weigh, but if we assume they will be at least fairly similar to previous iterations, they will add a considerable amount of weight as you try to maneuver across the Martian surface.
Completing a marathon in athletic clothing and sneakers is a monumental challenge in and of itself. I can only imagine that attempting such a feat (however slowly) in a spacesuit would be incredibly difficult and take an extraordinary amount of energy, strength, stamina and time.
The good(ish) news
There is one thing about traveling 26.2 miles on Mars that would make it easier than on Earth: the gravity. On Mars, a human would experience 62.5% less gravity than they would on Earth, which would certainly make the marathon a little easier on your joints — spacesuit excluded. However, I can only imagine that between the spacesuit and the lower gravity, covering such a long distance on Mars might be a bit awkward.
And while your joints might be glad for the reduced gravity, that doesn’t mean that a Mars trek would be a picnic. Astronauts who complete spacewalks from the International Space Station do so with almost no gravity, but they still report that these excursions are monumentally strenuous and challenging.
“It’s a lot of hard work on your muscles, mostly upper torso and arms and hands,” NASA spokesman Kelly Humphries previously told Space.com. “You’re essentially in an inflated balloon, which creates resistance against your movements. Crew members are notoriously ravenous when they come in from spacewalks.”
Boots on Mars
Exploring how astronauts might travel across the Martian surface isn’t just a thought experiment. As crewed missions journey to the moon for the first time in over 50 years with NASA’s Artemis program, we are once again reminded of the incredible time and hard work that it takes the teams across the agency and its partners to accomplish these missions.
Nevertheless, the space agency is pushing toward not just landing humans back on the lunar surface with Artemis 4, but with grander long-term plans of moon bases and longer residencies on the lunar surface. These efforts are part of an even longer-term plan by the agency, with support from commercial space companies, to one day send humans to Mars.
However soon a crewed flight to Mars may happen, one thing is for sure: it won’t be easy.
If some future Mars traveler dares to attempt a marathon, whether walking or even running on the Red Planet, they have their work cut out for them.