Astronaut Tim Peake ran the London Marathon from space

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Today (Apr. 24),  as almost 40,000 runners laced up their sneakers and made their way to the start line of the London Marathon, British astronaut Tim Peake wished his fellow runners good luck before beginning the race himself, 249 miles above the Earth.

Peake, who is with the European Space Agency, completed 26.2 miles strapped into a harness attached to a treadmill aboard the International Space Station in 3:35:21. In 1999, he completed the same race on the ground in 3:18:50.

As if running a marathon on the ground is hard enough, running one from space poses its own unique challenges because of the lack of gravity. On the one hand, no gravity means that the treadmill can’t have an incline; there’s no up or down in space. But on the other, it means Peake relied on a harness attached to a treadmill in order to feel his own weight. Although the bungie cords he was attached to only gave him a sense of 70% to 90% of his weight, Peake carried that weight on his shoulders. “It will be like running with a 10 to 20 kilogram (22 to 44 pound) backpack on his back, Patrick Jaekel, Peake’s trainer from the ESA, said in an interview.

There’s also no cooling breeze outside of the Earth’s atmosphere. Peake had fans to help keep him cool and evaporate some of the sweat his body produces, which can’t drip down without gravity’s help.

Despite being far away from the crowds in London, he could see course and hear the crowd cheer courtesy of the RunSocial app, which showed Peake a first-person view of the course as well as live coverage of the race. Jaekel even said that the speed of the treadmill matched the speed at which he sees the path ahead of him. His fellow crew team members were  at the ready to give him water, food, and a fresh shirt while he runs.

Peake is also not the first person to complete a marathon in space. In 2007, the NASA astronaut Sunita Williams completed the Boston Marathon from space in just under four and a half hours.

This post has been updated to include Peake’s finishing time.