Felix Baumgartner's space capsule at the launch site as the sun rose in Roswell, N.M. on Sunday.
ROSWELL, N.M. — As the winds calmed Sunday morning, Felix Baumgartner’s team made the critical decision to begin inflating an enormous helium balloon designed to carry him to the stratosphere, where he hoped to make the highest jump in history and become the first sky diver to break the speed of sound.
Once inflation began, the balloon could not be reused, and this was Mr. Baumgartner’s only remaining balloon. The other one had been inflated on Tuesday, his first attempt, but a gust of wind twisted it and forced the launch to be canceled. Obtaining a new balloon would take five weeks, and his team said that it would arrive too late for another attempt this year because it would be too windy in November.
The inflation began at 10:45 a.m. Eastern Standard Time, with launch planned for noon.
Launching the balloon is one of the most difficult and dangerous parts of the mission. To reach the thin air at 120,000 feet — 22 miles above the New Mexico dessert — requires the largest balloon ever used for a manned flight. Made of 40 acres of ultrathin plastic, it has been described as an inflated dry-cleaning bag that would fill the Los Angeles Coliseum.
When inflated and attached to the Mr. Baumgartner’s pressurized capsule, the balloon towers 750 feet above the ground. The winds at that level and at the ground must be less than three miles an hour for it to be launched safely, so that there is no chance of the balloon lurching and smashing the capsule into the ground. Once the balloon rises above 4,000 feet, Mr. Baumgartner can parachute to safety, but below that altitude there is not enough time for him to get out safely, which is why engineers call it the Dead Zone.
Mr. Baumgartner, wearing a pressurized suit to survive in the near vacuum at the edge of space, planned to step off the capsule above 120,000 feet and quickly break the sound barrier, reaching a speed of more than 700 miles an hour. He expected to free fall for five and a half minutes before deploying his parachute a mile above the ground.
Mr. Baumgartner, a professional daredevil, was backed by a NASA-style mission control operation at an airfield in Roswell that involved 300 people, including more than 70 engineers, scientists and physicians who have been working for five years on the project, called Red Bull Stratos, after the drink company that has financed it.
While building the customized suit and capsule, the team of aerospace veterans had to contend with one crucial uncertainty: What happens to the human body when it breaks the sound barrier? There was also one major unexpected problem for Mr. Baumgartner, 43, an Austrian daredevil and former paratrooper known to his fans as Fearless Felix.
Although he had no trouble jumping off buildings and bridges, and across the English Channel in a carbon-fiber wing, he found himself suffering panic attacks when forced to spend hours inside the pressurized suit and helmet. At one point in 2010, rather than take an endurance test in it, he went to the airport and fled the United States. With the help of a sports psychologist and other specialists, he learned techniques for dealing with the claustrophobia.
Besides being his most complex challenge, the stratospheric jump is also the one most likely to be made into a buddy movie, thanks to the friendship that he developed with Joe Kittinger, the retired Air Force colonel who for more than a half century held the records for the highest jump, longest free-fall and fastest speed. Mr. Kittinger, now 84, helped train Mr. Baumgartner to break his own record, and he was the voice guiding Mr. Baumgartner during the long ascent as they went through the pre-jump checklist.
Mr. Kittinger, a former test pilot, set his records in a 1960 trip to the stratosphere. Early during that ascent, also over New Mexico, in an Air Force balloon, one of his pressurized gloves leaked, but he was so determined to keep going that he did not report the problem even after his hand swelled to twice its normal size.
Ignoring the pain, he rode the balloon up to 102,800 feet and said a short prayer — “Lord, take care of me now” — before stepping off. He reached a speed of 614 miles an hour and spent 4 minutes, 36 seconds in free fall. Those records were repeatedly challenged during the ensuing half century, sometimes with fatal consequences.
Besides aiming at records, the engineers and scientists on the Red Bull Stratos team are gathering and publishing reams of data intended to help pilots, astronauts and perhaps space tourists survive if they have to bail out.
“We’re testing new spacesuits, escape concepts, and treatment protocols for pressure loss at extreme altitudes,” said the Red Bull Stratos medical director, Dr. Jonathan Clark, who formerly oversaw the health of space shuttle crews at NASA. “There are so many things that could go wrong here that we’re pushing the technical envelope.”
The original stratospheric jump by Mr. Kittinger was part of an Air Force program studying ways to help pilots survive high-altitude bailouts. It experimented with a small parachute, called a drogue, to prevent the jumper’s body from going into a flat spin — a hazard that almost killed Mr. Kittinger in a preliminary jump in 1959. When his drogue chute became entangled around his neck, his body spun at 120 revolutions a minute, causing him to blackout until his emergency parachute automatically deployed. An improved version of that drogue chute is now used by military pilots who have to bail out in the ejection-seats used by pilots.
Mr. Baumgartner was equipped with his own customized high-tech drogue chute, but it was there as a precaution — to be activated only if he began spinning out of control. Otherwise, he planned to avoid using it because the drogue chute would have slowed him down just enough to prevent him from going supersonic.
To avoid spinning out of control, Mr. Baumgartner practiced doing a bunny hop out of the capsule and controlling his body so that it rotated into headfirst position for the supersonic descent.
“We try to anticipate as much as we can about supersonic speed,” Dr. Clark said before the jump, “but we don’t really know, because nobody has done this before.”
