How long would it take to run to space?

Space travel usually involves rockets and millions of dollars, but what if you could simply run there? While physically impossible, breaking down the numbers offers a fascinating look at the sheer scale of space travel and how long it would take even the most dedicated athlete to reach key milestones in space—on foot.

The first hurdle: the Earth’s atmosphere

The edge of space isn’t as far away as it might seem. The commonly accepted boundary, the Kármán Line, sits at 100 km above Earth’s surface, though NASA considers space to begin at 80 km. As reported on YouTube by tech explainer Cleo Abram, if you could maintain a steady running speed of 10 km/h you would reach:

48 minutes—The point where oxygen levels become too low to breathe (that 10K training might help, but good luck with the altitude adjustment).

One hour—The altitude where commercial planes cruise at ~12 km (more airborne traffic than your usual race start—and mind the turbulence).

Eight hours—NASA’s official boundary for space at 80K (time to swap your hydration vest for an oxygen tank—and your super shoes won’t help you up here).

10 hours—The Kármán Line (100K), widely recognized as the edge of the atmosphere (an ultrarunner’s dream milestone—just don’t expect a finisher’s medal).

Stranded astronaut was first to run a space marathon

Beyond the atmosphere: reaching satellites and the ISS

After crossing into space, you’d still have a long way to go before reaching anything significant. The lowest satellites orbit at 160 km, which would take about 16 hours of non-stop running at 10km/hr. The International Space Station (ISS), where astronauts live and work, orbits at 400 km—a 40-hour run at 10 km/hr, with no stops to refuel your hydration vest or consult with your crew.

Running to the moon: the ultimate ultra

Reaching the moon, sitting 384,400 km away, would take 1,600 days—or more than four years—of non-stop running at 10 km/h. Of course, no human could realistically sustain that pace indefinitely. Even elite ultrarunners struggle to hold a steady speed for more than a day.

For context, Aleksandr Sorokin, the Lithuanian multi-day racing phenom, holds the world record, at 319.7 km, for the farthest distance run in 24 hours, maintaining a blistering pace (over the distance) of 13.7 km/h. And he’s the fastest person in history at that duration. Now imagine keeping even a much slower pace, not just for a day, but for months or years. The sheer physical and mental endurance required would make this the ultimate test of human limits.

If you aimed for a more realistic approach—say, running a marathon per day—it would take nearly 36 years to reach the moon. That’s nearly half a lifetime of running, all for a one-way ticket to lunar solitude. If you’d rather aim for a planet, Mars, at 225 million km away, would take 2,564 years to reach at a speed of 10 km/h.

A more realistic challenge

While running to space isn’t an option, imagining the effort helps put its scale into perspective. Space tourism is becoming a reality, but for now, runners will have to plan their adventure races in a more earthly setting. Maybe start with a vertical kilometre before setting your sights on the stars.