A team of French doctors are planning to carry out the first operation on a human being under weightless conditions in a specially adapted aircraft.
It is hoped the trial will be a first step to performing surgery in space.
The doctors will be removing a benign tumour from the arm of a volunteer as the plane makes a series of manoeuvres to create weightlessness.
The surgeons will be working strapped to the sides of the plane while the patient is held inside a plastic tent.
Specially designed instruments have been fitted with magnets to attach them to the metal operating table.
During the three-hour flight above south-west France, the specially designed Airbus A300 Zero-G will be making parabolic swoops to create zero gravity.
The operation will be carried out in a series of 20-second periods of weightlessness.
I just hope nobody throws up in the middle of the operation