It was the first time for the two to assemble the suits in zero-gravity as it is impossible to create a real zero-gravity condition on Earth.

Two guinea pigs then tested them in real zero-gravity conditions. The results were videotaped but are considered so sensitive that even Nasa was only given a censored version.

Unfortunately, the standard definition of a second relies on what the atom does at a temperature of absolute zero. Real clocks need to run at room temperature, where the shell of electrons puffs up.