A Channel 4 reality show is aiming to trick contestants into thinking they have been launched into space.
Johnny Vaughan will present the show from a secret location
Space Cadets, which will air next month, will tell nine people they are to visit space thanks to a Russian tourism agency.
They will be told they are being taken to a Russian training base - but it will, in fact, be a secret UK location.
Channel 4 executives have admitted the joke could be on them if the participants cotton on to the stunt.
The channel has lined up a stand-in schedule just in case the 10-day series beginning on 7 December does not go to plan.
The show, presented by Johnny Vaughan, has been created by Endemol, the firm behind Big Brother.
The contestants will be told four of them have been to be selected to go on a "space flight" after training.
Among the winners will be one of three actors in the group.
Their shuttle will be a Hollywood creation, made originally for the Clint Eastwood film Space Cowboys, with sounds created by a special effects specialist.
A custom-built screen just outside the shuttle will attempt to provide the illusion of a view of Earth.
But producers will not have to recreate weightlessness because the contestants are to be told their orbit will take them to Near Space, not Deep Space, where they could experience the sensation.
"We've taken a big risk with Space Cadets, and we don't know who will have the last laugh," said Channel 4's factual entertainment commissioning editor Angela Jain.
"But we're hoping it's going to be a really entertaining and unique event."
The participants, who answered an advert for "thrill-seeking" members of the public, will be "trained" for space in a disused airbase.
They were selected because they showed a trait of "suggestibility" during psychological testing, said Channel 4.
About one fifth of what they learn in preparation will be fiction but the remainder will be based on genuine training techniques.