Oliver Daemen is to become the youngest person to fly to space when he joins Jeff Bezos on the first human flight by his space company on July 20.

The 18-year-old will fly in place of an anonymous $28 million winning bidder of a public auction.

The winner of the auction could not fly on the mission “due to scheduling conflicts”, Jeff Bezos’ space venture Blue Origin said.

Oliver Daemen is the son of Somerset Capital Partners CEO Joes Daemen.

Joes Daemen had secured a seat on the second flight but was moved up to the first when the winning bidder pulled out, Blue Origin said. He then chose to instead fly his son, who is a physics student.

He will join 82-year-old Wally Funk, who will become the oldest ever person in space. Jeff Bezos and his brother Mark will make up the rest of the passengers on the New Shepard rocket.

The previous winner of the auction has remained anonymous, even as the launch edged closer, and the nature of the “conflicts” which led to their withdrawal have not been disclosed.

Blue Origin has not said how much Oliver Daeman’s ticket cost.

It said the flight will fulfill a lifelong dream for the teenager, “who has been fascinated by space, the Moon and rockets since he was four”.

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Blue Origin plans to launch its passengers more than 62 miles above the Earth’s surface, allowing them to experience microgravity.

The capsule will then return to Earth using parachutes on a trip expected to last about 10 minutes.

Jeff Bezos is one of the world’s richest people.

He created Blue Origin in 2000 and announced last month that he and his brother would embark on the flight – describing it as something he had wanted to do “all my life”.

The flight comes after billionaire Richard Branson successfully reached the edge of space on board his Virgin Galactic rocket plane last week.