NAIROBI, Aug. 15 (Xinhua) -- Olympic marathon champion Eliud Kipchoge has likened running a marathon in under two hours to man landing on the moon.

The world marathon record holder says he has no doubts he will make history at the INEOS 1:59 Challenge in Vienna, Austria in October.

"Some people believe it is impossible. But my team believe it is possible. We will prove the critics wrong," Kipchoge said on Thursday.

The window set aside for the race is October 12 to 20, with the exact date of the challenge to be decided nearer the time when an accurate weather forecast is available.

At his first attempt in 2017 in Monza, Italy, Kipchoge missed out on the milestone by just 26 seconds, though he says that experience has given him the confidence to try again.

"I was like a boxer who goes in the ring and doesn't know what will happen," he said of his 2017 attempt. "But this time I am prepared, and I know what will happen."

The 34-year-old has won Olympic and World Championship gold medals and his eight major marathon successes include four victories in London.

He also holds the world record over the 26.2-mile distance: 2:01:39, set in Berlin in 2018. However, for Kipchoge, completing the INEOS 1:59 Challenge would mean much more to him than any of his previous glories.

"It's more important," he said. "This is about history and making a mark in sport. It's like being the first man to go to the moon, I will be the first man to run under two hours. I'm really excited and looking forward to this historic day."

Kipchoge was speaking from his training base in Kaptagat, Kenya where he has been preparing for the INEOS 1:59 Challenge in much the same as for any other marathon.

"Nothing much has changed, the training is the same," Kipchoge said. "What has changed is the mental preparation, I have a free mind and am ready to go. I'm really enjoying the experience.

"My training is simple. I trust in my coaching system, I trust in my team and that is what makes my mind strong. I can't lie to myself if I am going to be successful."

Kipchoge believes he has learned lessons from his first attempt at a sub two-hour marathon in Monza and says the Vienna course will give him every chance of breaking the two-hour barrier.

"Monza was a big, big successful event and I enjoyed the experience. Vienna is a very flat and low course and that makes a difference. Being a straight course can help me run at a comfortable pace in a comfortable time," he said.

The London champion, however, says he has no idea if he is at his peak.

"After doing it in Vienna, many athletes will believe for themselves that it is possible," he said.

"I don't know what time is the limit, I don't have any limits. But my target is 1:59. I don't know if I am at my peak now, but I am at the right age to make history," he added.