British astronaut Tim Peake finished the 26.2 mile course at the International Space Station with an approximate time of 3:35.21, the European Space Agency tweeted.

In a video message played at the starting line, Peake told his fellow competitors, "I'm really excited to be able to join the runners on earth from right here on board the Space Station. Good luck to everybody running, and I hope to see you all at the finish line."

Running in space has serious challenges. Peake told reporters earlier this week that it was challenging to get comfortable with the harness system, which he says can be compared to running with a "clumsy rucksack on."

As The Guardian states, "weightlessness is not kind to astronauts. The perceived lack of gravity deconditions the body in a number of ways."

But according to Peake, the microgravity conditions are actually a "perfect environment" for post-race recovery, "The moment you stop running and the moment you get off that bungee system, your muscles are in a completely relaxed state. And I do think we recover faster up here from any kind of aches or sprains."

When Peake talked to reporters, he hadn't yet decided what to eat for a pre-race breakfast. He was thinking about baked beans, sausage and eggs, but added that food in microgravity doesn't "settle very well."

Peake is the second astronaut to participate in a marathon from the International Space Station. Sunita Williams ran the Boston Marathon while in orbit in 2007.