Extreme athlete Felix Baumgartner has cancelled this morning's attempt to break the sound barrier in a 37km freefall from the edge of space.
He had hoped to become the first skydiver to break the sound barrier, however persistent high winds caused his team to pull the plug on the attempt shortly before 7am (NZT).
While the high wind had dogged the attempt from early morning, the 43-year-old former military parachutist from Austria entered his capsule shortly before 11am MDT (6am NZT).
Crews began the hour-long process of inflating the 55-storey, ultra-thin and easy-to-tear helium balloon that was to take him into the stratosphere for the jump.
Those plans were in question before sunrise, when winds at 212m above ground - the top of the balloon - were 33kmh, far above the 5kmh maximum for a safe launch, said mission meteorologist Don Day.
After sunrise, Day said there were indications the upper level winds might calm, so the team pushed the launch window from 10am to noon (7am NZT) at the latest.
The balloon had been scheduled to launch about 7am (2am NZT) from a field near the airport in a flat dusty town that until now has been best known for a rumored 1947 UFO landing.
Baumgartner was to make a nearly three-hour ascent to 120,000 feet (36,576m), then take a bunny-style hop from his pressurised capsule into a near-vacuum where there is barely any oxygen to begin what was expected to be the fastest, furthest freefall from the highest-ever manned balloon.
Among the risks of the mission: Any contact with the capsule on his exit could tear the pressurised suit. A rip could expose him to a lack of oxygen and temperatures as low as 70 degrees below zero. It could cause potentially lethal bubbles to form in his bodily fluids, a condition known as "boiling blood."
He could also spin out of control, causing other risky problems.
The event, if it is rescheduled, would be covered by nearly 30 cameras on the capsule, the ground and a helicopter. But organisers said there would be a 20-second delay in their broadcast of footage in case of a tragic accident.
Baumgartner has made two practice jumps, one from 24km in March and another from 29km in July.
"With these big moments, you get a kind of sense that the energy changes," he said. "It really is just kind of a heightened energy. It keeps you on your toes. It's not nervousness, it's excitement."
During the ascent, Walshe said, the team would have views from a number of cameras, including one focused directly on Baumgartner's face. Additionally, they would have data from life support and other systems that showed things like whether he was getting enough oxygen.
While Baumgartner hoped to set four new world records, his freefall was 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 expected to hit a speed of 1110kmh or more before he activated his parachute at 2895m above sea level, or about 1524m above the ground in southeastern New Mexico. The total jump should take about 10 minutes.
His medical director was Dr Jonathan Clark, a NASA space shuttle crew surgeon who lost his wife, Laurel Clark, in the 2003 Columbia accident. No one knew what happened to a body when it broke the sound barrier, Clark said.
"That is really the scientific essence of this mission," said Clark, who is dedicated to improving astronauts' chances of survival in a high-altitude disaster.
Clark told reporters he expected Baumgartner's pressurised spacesuit to protect him from the shock waves of breaking the sound barrier.
Following a successful jump, NASA could certify a new generation of spacesuits for protecting astronauts and provide an escape option from spacecraft at 36,576m, he said.
Currently, spacesuits were certified to protect astronauts to 30,480m, the level Kittinger reached in 1960. Kittinger's speed of 988kmh was just shy of breaking the sound barrier at that altitude.