Austrian daredevil Felix Baumgartner today jumped from the edge of space, freefalling for several minutes before opening his parachute, descending and landing safely back on Earth.
It was not immediately clear if the 43-year-old succeeded in breaking the sound barrier with the fastest freefall ever as he plummeted from an altitude of more than 39 kilometres and fell for over five minutes.
Television pictures showed him opening his parachute at about 5,000 feet and guiding himself back toward ground.
Baumgartner had taken more than two hours to get up to the jump altitude. He had already broken one record, before he even leapt: the previous highest altitude for a manned balloon flight was 113,740 feet, set in 1961.
A minor problem developed as the capsule ascended: a heater failed on Baumgartner's helmet faceplate, meaning it was becoming fogged up when he exhaled. But after considering options they decided to go ahead with the jump.
He had been due to jump from 120,000 feet, but the balloon went higher than expected, to 128,000 feet.
The Red Bull Stratos mission was the second attempt for the skydiver, following an initial bid last week that was aborted at the last minute due to winds.
The biggest risk Baumgartner faced was spinning out of control, which could have exerted G forces causing him lose consciousness. A controlled dive from the capsule was essential, putting him in a head-down position to increase speed.
More gruesomely, the skydiver's blood could have boiled if there were the slightest tear or crack in his pressurised spacesuit-like outfit, due to instant depressurisation at the extreme altitude.
Temperatures of 90 degrees below zero Fahrenheit (minus 68 Celsius) could also have unpredictable consequences if his suit somehow fails.