European Space Agency astronaut Tim Peake has insisted he won’t be short on sources of motivation when he aims to become the first man to run a marathon in space on Sunday ©London Marathon

European Space Agency (ESA) astronaut Tim Peake has insisted he won’t be short on sources of motivation when he aims to become the first man to run a marathon in space on Sunday (April 24).

The Briton will attempt the 26.2-mile challenge on the same day that 37,000-plus runners take on the world-famous London Marathon course.

But unlike those on Earth, the 43-year-old will be tethered to a treadmill onboard the International Space Station (ISS), 400 kilometres above.

Peake, who completed the 1999 London Marathon in 3 hours 18min 50sec, will be monitored by the European Astronaut Centre in the German city Cologne to ensure he will maintain peak fitness for his return to Earth on June 5.

He will be able to take part due to the development of the Digital Virgin Money London Marathon, an interactive virtual-reality video, which was created by London Marathon Events in partnership with the digital fitness technology company RunSocial.

"One of the main memories I have of 1999 when I ran the London Marathon before was the atmosphere and the crowd and the other competitors taking part and that spirit really lifted me the entire way through the race," Peake said via a video link here today.

"So in order to try and get some of that up here on board the space station, I’ve got a couple of things.

"Firstly, I’ve got the RunSocial app so I’ll actually be looking at the route that I’m running and I’ll be running alongside everybody else who is running the digital version of the London Marathon.

"And hopefully, I’ll also get a television sent up to the space station so at times I’ll be able to actually see what’s going on with the real race down in London.

"It will be a huge boost for me to be able to know that I’m running alongside everyone down there."

Libby Jackson (left) and Jonathan Scott (right) will attempt to break the respective male and female Guinness World Records for completing the marathon race in space suits
Libby Jackson (left) and Jonathan Scott (right) will attempt to break the respective male and female Guinness World Records for completing the marathon race in space suits ©London Marathon

A team of sports scientists on Earth will determine how much harness force Peake will use during his run.

If they opted for a modest force - just enough to keep him from floating off the treadmill - he could likely run the marathon in near world-record time, but Peake is determined that his effort should be just as challenging as running the race on Earth.

"I don’t think I’ll be setting any personal bests," he admits.

"I’ve set myself a goal of anywhere between 3 ½  to 4 hours."

Like thousands of goal-setting runners on Earth, Peake will run the marathon distance for charity.

The former Army Air Corps test pilot will raise awareness for The Prince’s Trust, which will have a team running on Earth - Team Astronaut - while he’s running on the ISS.

Peake became an ambassador for The Prince’s Trust last year.

Today saw the opening of the London Marathon Expo at London Docklands' ExCeL Exhibition Centre, where thousands of runners are expected to register for the 36th edition of the race over the following four days.

It was opened by Dr Jonathan Scott, who leads the Medical Projects and Technology Team in the ESA's Space Medicine Office, and Libby Jackson, the Astronaut Flight Education Programme Manager at the UK Space Agency.

Scott and Jackson worked closely with Peake on Earth to prepare him for his mission, but will compete against their colleague on Sunday as they attempt to break the respective male and female Guinness World Records for completing the marathon race in space suits.