A parachutist hopes to become the first man to break the sound barrier by jumping from a balloon 25 miles high.
Michel Fournier, 63, a retired Army officer, will plunge at up to 1,000mph, breaking the record for the highest balloon jump into the bargain.
He will defy temperatures of -100C, solar radiation and oxygen deprivation, reports the Daily Mirror.
A modified space suit will protect him from the sonic boom.
He said: "It really is a leap into the unknown. Nobody knows much about the effect on the human body of passing the sound barrier."
Fournier, a former para who served in Algeria, was one of three candidates who took part in a French Army plan to jump 125,000 feet in the 80s.
This guy is mad 