A British astronaut will attempt to become the first man to run a marathon in space, sort of. Tim Peake will run a digital version of next year's London Marathon on a treadmill as the International Space Station orbits the Earth, at the same time as more than 37,000 people run in the race on the ground. To combat weightlessness, Peake will wear a harness that tethers him to the treadmill as he runs, and he will watch a video of the London course on a big screen in front of him. He'll be the first man but not the first astronaut: NASA's Sunita Williams, a woman, ran on a treadmill in 1997 at the same time as the Boston Marathon. The London Marathon is on April 24.
Peake ran the London Marathon in 1999 in 3 hours, 18 minutes, 50 seconds. He said he is not expecting to beat that time next year because his medical team will be monitoring his preparations and run carefully to ensure he is at optimum fitness for his return from space eight weeks later. He hopes to finish in under 4 hours. (Read more marathon stories.)