Extreme athlete and skydiver Felix Baumgartner has cancelled his planned death-defying 23-mile free fall into the New Mexico desert because of high winds.
The 43-year-old former military parachutist from Austria had hoped to become the first skydiver to break the sound barrier and shatter three other world records.
But the weather forced his team to cancel his planned ascent in a 55-storey, ultra-thin helium balloon that was to take him to the stratosphere. Because the balloon is so delicate, it could only take flight if winds were 2mph or below.
Those plans were in question before sunrise, when winds at 700 feet above ground - the top of the balloon - were 20mph, far above the 3mph maximum for a safe launch, mission meteorologist Don Day said.
With winds calming, they began the launch process, with Baumgartner suiting up and entering the capsule. During the inflation, a live online feed showed winds whipping the balloon around.
The balloon had been scheduled to launch about 7am local time from a field near the airport in a flat dusty town that until now has been best known for a rumoured 1947 UFO landing.
Baumgartner was to make a nearly three-hour ascent to 120,000 feet, then take a bunny-style hop from a pressurised capsule into a near-vacuum where there is barely any oxygen to begin what is expected to be the fastest, farthest free-fall from the highest-ever manned balloon.
Among the risks: Any contact with the capsule on his exit could have torn the pressurised suit. A rip could have exposed him to a lack of oxygen and temperatures as low as 70 degrees below zero. It could have caused potentially lethal bubbles to form in his bodily fluids, a condition known as "boiling blood". He could also have spun out of control, causing other risky problems.
While Baumgartner hopes to set four new world records when he jumps, his free-fall is more than just a stunt. His dive from the stratosphere should provide scientists with valuable information for next-generation spacesuits and techniques that could help astronauts survive accidents.
Jumping from more than three times the height of the average cruising altitude for jetliners, Baumgartner expects to hit a speed of 690 mph or more before he activates his parachute at 9,500 feet above sea level, or about 5,000 feet above the ground in south-eastern New Mexico. The total jump should take about 10 minutes.