Six-time space shuttle crew surgeon Dr. Jon Clark...

Six-time space shuttle crew surgeon Dr. Jon Clark was the head of the medical team designed to keep “space diver” Felix Baumgartner safe as he jumped from 128,100 feet this Sunday, becoming the first man to break the speed of sound.

At TEDxUSC this April, he gave a talk detailing his role in Red Bull Stratos, and explained some of the dangers inherent in this sort of mission, dangers that he is dedicated to keeping astronauts from having to face. “This Stratos mission is a very personal journey for me,” he said in his talk. “My wife was on the Columbia mission, and she perished with the rest of her crew. And I dedicated my life after this to improving crew escape and survival in spacecraft.”

From his talk:

The atmosphere—that bounds the earth, that gives us life—is like four sheets of paper on a basketball. And the lowest sheet—the bottom of the lowest sheet—is where we live and what we can survive in. Above that layer and we go into the death zone: the stratosphere.

…[T]he extreme low pressures of the vacuum of space…can lead to hypoxia and inadequate oxygen; it can also lead to decompression sickness or the bends…The worst problem that you can face is in the vacuum of space—above 63,000 feet—is that the water that makes up 70% of our body can turn spontaneously from a liquid state to a gaseous state…this is the phenomenon called ebullism, where your blood boils. And this is actually survivable if you can get back to Earth within a minute or so. People that have survived this say the thing that they remembered is their tongue boiling.”

“A big part of our test program is to learn everything we can from this program,” he said. “The lessons learned from this will be applied to future spacecraft…My team—made up of physicians and physiologists and rescue specialists,” he said, “are all volunteers…dedicated to one thing: bringing [Felix] home safely.”

And this past Sunday we learned that Dr. Clark and his team were successful, guiding Felix to space and home again.

(Photo credits: © Red Bull Stratos/Red Bull Content Pool and © Jay Nemeth/Red Bull Content Pool)

Watch Jon’s talk at TEDxUSC here.