Photograph courtesy Joerg Mitter, Red Bull Content Pool

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During pre-jump prep, pilot Felix Baumgartner sits in the capsule meant to take him to the edge of space.

Photograph courtesy Joerg Mitter, Red Bull Content Pool

Supersonic Skydive at a Standstill: Winds Ground Felix Baumgartner

Red Bull mission at mercy of Mother Nature—and gargantuan, gossamer balloon.

Between ill winds and uncooperative electronics, Felix Baumgartner just couldn't catch a break Tuesday. After recovering from a communications malfunction within his capsule, the sky diver's supersonic-skydive launch was canceled at 11:42, mountain time, when gusting winds above a Roswell, New Mexico, runway threatened his thin-skinned helium balloon.

The Red Bull Stratos team hopes to begin anew on Sunday. For now, they're watching the winds—and waiting. "It takes patience to get just the right weather conditions," team meteorologist Don Day told National Geographic News late last week.

"Takeoff will not be authorized if winds exceed about 2 mph [3.2 kph] from ground level through 800 feet [244 meters] in altitude," Day said.

Gusts like today's—which were focused at about 700 feet [213 meters], near the crest of the balloon—could possibly tear Baumgartner's 0.0008-inch-thick (0.02-millimeter-thick) plastic balloon or overturn the stabilizing crane that prevents the pressurized capsule from ascending too soon.

Either would have meant trouble for the Austrian pilot and parachutist.

"There are hazards all through the flight," Red Bull Stratos Medical Director Jon Clark said. "On the ascent, it starts with the potential for balloon failure in the first few thousand feet, when there wouldn't be enough time for the capsule parachute to deploy or for Felix to bail out."

Baumgartner to Break Records

If all goes to plan Sunday, Baumgartner will climb to around 23 miles (37 kilometers) in a pressurized capsule attached to history's largest helium balloon—55 stories tall and as wide as a football field. When the high-altitude weather is right and all systems are go, he'll exit the capsule in a pressurized suit and free-fall to Earth.

Seven years in the making, the jump is expected to break records for the highest, fastest, and longest-duration skydive. Baumgartner's team estimates he will reach Mach 1.2—roughly 690 miles (1,110 kilometers) an hour—and free-fall for five and a half minutes before opening a parachute at 5,000 feet (1,524 meters).

But first, Baumgartner will have to run a gauntlet of potentially deadly risks.

Should his pressurized suit tear, for starters, the lack of atmospheric pressure at extreme altitudes could cause Baumgartner's blood to boil. And if his body goes into a so-called flat spin—rotating perhaps hundreds of times a minute—he could suffer extreme eye and brain injury.

What's more, the dangers of exceeding the speed of sound without the propulsion, or protection, of a vehicle are unknown.

"We try to anticipate as much as we can about supersonic speed, but we really don't know, because nobody has done this before," Clark said.

"Our analysis of the aerodynamic loads indicate the dynamic pressure at 120,000 feet [36,600 meters] will not be excessive, so we don't think he will encounter shock-shock interaction"—damage due to shock waves generated when the sound barrier is broken. "But we don't know for certain."

Passing the Torch

If Baumgartner does become the first human to achieve supersonic speed with just his body—and without breaking his body—he will break new scientific ground, in addition to a raft of records.

The current free fall record is held by Joseph Kittinger, a retired U.S. Air Force colonel and current Red Bull Stratos team member, who plummeted 19.5 miles (31.3 kilometers) on August 16, 1960. (See classic pictures of Kittinger's skydive.)

More than one man has died trying to break the 52-year-old record, but Kittinger has faith in Baumgartner, whom he calls dedicated and sincere. And, as he says in the National Geographic Channel documentary Space Dive, "The only way to ensure safety is to stay on the ground."

More Supersonic-Skydive Coverage

In November, get the story behind Baumgartner's jump in Space Dive, airing on the National Geographic Channel (Date TBD). (The Channel is part-owned by the National Geographic Society, which owns National Geographic News.)