Supersonic Jump, From 23 Miles Up

Although not strictly 'Aviation', I thought this would be of interest on this forum, and the discussion might be more thoughtful than in P&R...... Experienced jumpers and ex-military types (Taz?) may have some interesting viewpoints, especially on the issues of the body going trans- then supersonic......comments?

A Supersonic Jump, From 23 Miles in the Air

Ordinarily, Felix Baumgartner would not need a lot of practice in the science of falling.
He has jumped off two of the tallest buildings in the world, as well as the statue of Christ in Rio de Janeiro (a 95-foot leap for which he claimed a low-altitude record for parachuting). He has sky-dived across the English Channel. He once plunged into the black void of a 623-foot-deep cave, which he formerly considered the most difficult jump of his career.

But now Fearless Felix, as his fans call him, has something more difficult on the agenda: jumping from a helium balloon in the stratosphere at least 120,000 feet above Earth. Within about half a minute, he figures, he would be going 690 miles per hour and become the first skydiver to break the speed of sound. After a free fall lasting five and a half minutes, his parachute would open and land him about 23 miles below the balloon.

At least, that’s the plan, although no one really knows what the shock wave will do to his body as it exceeds the speed of sound. The jump, expected sometime this year, would break one of the most venerable aerospace records. For half a century, no one has surpassed (one person died trying) the altitude record set by Joe Kittinger as part of an Air Force program called Project Excelsior.

In 1960, Mr. Kittinger, then a 32-year-old Air Force pilot, jumped from a balloon 102,800 feet above the New Mexico desert. Today, at 81, Mr. Kittinger is a retired colonel and part of the Red Bull Stratos team working on Mr. Baumgartner’s jump, which is being financed by the energy-drink company.

“For 50 years,” Mr. Kittinger said, “I’ve gotten phone calls from all over the world, people wanting to break my record — one a month, sometimes two a month. But I stayed away from them because they didn’t have any idea what the challenge was. What attracted me to Red Bull was their methodological approach to safety and to providing scientific benefits.”

More than three dozen veterans of NASA, the Air Force and the aerospace industry have been working for three years to plan the jump, build a balloon and pressurized capsule, and customize an astronaut’s suit for Mr. Baumgartner. Besides aiming at records, they’re doing physiological research and developing procedures for future astronauts to survive a loss of cabin pressure or an emergency bailout in the stratosphere.

One of the chief concerns has been to avoid the problem that almost killed Mr. Kittinger during Project Excelsior. He was supposed to be stabilized during his fall by a small drogue parachute, but on one training jump in 1959 it did not open because the cord got tangled around his neck.

As a result, Mr. Kittinger’s body went into a spin that reached 120 revolutions per minute as he plummeted more than 60,000 feet. He blacked out and regained consciousness only after his reserve parachute opened automatically about a mile above the ground. When he came to, he later wrote, he first assumed he must have died, but then he spotted the parachute’s canopy above him and made a sudden realization: “I am impossibly, wonderfully alive.”

Mr. Baumgartner hopes to remain stable and conscious throughout his longer fall without relying on a drogue parachute. He plans to avoid spinning by adjusting the angle of his body and keeping his arms at his side.

This stabilizing technique would ordinarily be fairly easy for an expert like Mr. Baumgartner, 41, a former paratrooper in the Austrian Special Forces and a veteran of more than 2,500 jumps from planes, cliffs and assorted landmarks. But to survive the stratosphere’s near vacuum and frigid temperatures, he will need a sealed helmet and a pressurized suit.

Would he be able to do midair maneuvers in such a bulky contraption? To find out, Mr. Baumgartner and his team recently went to a wind tunnel in Perris, Calif., near Los Angeles, and put the suit through its paces.

Team members suited up Mr. Baumgartner, turned on the oxygen in his helmet and attached a pack to his chest containing equipment to record his vital signs, track his position using GPS satellites and heat his helmet’s visor to keep it from fogging.

By the time the suit was inflated to its full pressure of three pounds per square inch, he looked like a robotic version of the Incredible Hulk. As he walked stiffly into the wind tunnel, it was easy to see why astronauts lack a certain grace.

But once Mr. Baumgartner was inside, held aloft by air blowing upward at 130 miles per hour, he looked comfortable enough, much to the relief of the engineers. By adjusting his arms and legs, he could shoot up in the tunnel or bring himself down. Most important, with his body angled at 45 degrees to the ground, he could maintain the desired arrowlike stance: head first, arms and legs pointing backward in a V shape called the delta position.

“It was difficult, but it worked,” Mr. Baumgartner said after emerging from the tunnel. “Now I’m confident I can handle the suit in regular free fall as long as we’re not breaking the speed of sound. But as soon as it goes from subsonic to transonic to supersonic, we don’t know what to expect.”

Plenty of planes have broken the sound barrier, but transonic humans are a mystery, said Art Thompson, the technical project director for the Red Bull Stratos mission, and a former Northrop engineer who worked on the B-2 stealth bomber.

“You can run a lot of models, but with the human body you’re not dealing with a hard surface or a ballistic shape,” Mr. Thompson said. “You’ve got this rounded bulbous helmet, and the shoulders and the feet sticking out, and everything starts to happen at different times. Parts of your body may be going supersonic while others aren’t, causing flutter waves pulling back and forth among the surfaces.”

Could such waves harm the body? Could they create disastrous turbulence?

“We just don’t know what will happen to Felix and the suit when he goes supersonic,” said another Stratos engineer, Mike Todd, who worked on high-altitude suits for the Air Force’s spy-plane pilots with the renowned Skunk Works research division of Lockheed. “Felix could slip right through it, but if half the suit’s supersonic and the other half isn’t, there could be turbulence that knocks him out of control.”

Such risks are one reason why Mr. Kittinger’s record has stood for half a century. Air Force and NASA officials have become understandably reluctant to explain potential mishaps to Congressional committees. (To debate the risks and benefits of this project, go to nytimes.com/tierneylab.)

But private adventurers have more freedom to take their own risks. The Stratos medical director, Dr. Jonathan Clark, who formerly oversaw the health of space shuttle crews at NASA, says that the spirit of this project reminds him of stories from the first days of the space age.

“This is really risky stuff, putting someone up there in that extreme environment and breaking the sound barrier,” Dr. Clark said. “It’s going to be a major technical feat. It’s like early NASA, this heady feeling that we don’t know what we’re up against but we’re going to do everything we can to overcome it.”

JOHN TIERNEY
March 15, 2010

 

What about attitude control vis a vis turbulence during his speed changes from subsonic to transonic to supersonic and back transonic to subsonic? Seems like a big risk of getting out of shape and spinning/tumbling? that could hurt......any control measures beyond luck?