Credit: Courtesy Red Bull

On October 14, 24 miles above Roswell, New Mexico, Mission Control radioed 43-year-old Austrian skydiver Felix Baumgartner the go-ahead. He unhooked his seat belt, stepped from the doorway of his pressurized capsule, and jumped. His mission: to hurtle from the upper portion of Earth's atmosphere to the ground – and survive. "I was standing there," says Baumgartner, "and I thought, 'There's not a lot of people who've stood at this height.'"

Just seconds into his descent, Baumgartner fell into a potentially fatal spin. "There's only one way the blood can get out during a spin," he says. "Through your eyeballs." He countered the spin by sticking one of his arms and legs out and using the resistance to slow the motion and stabilize his position.

For four and a half minutes, Baumgartner bulleted down, becoming the first man to break the speed of sound without a vessel, topping out at an earsplitting 833 miles per hour. At 5,300 feet, his parachute released, and he began to float to the ground.

Prior to Baumgartner's record-breaking jump, his biggest achievement was leaping off the world's highest bridge and building. Born in Austria, he started skydiving at the age of 16 and was part of his country's military demonstration team (similar to the U.S. Army parachute team), and then became a professional skydiver and BASE jumper. Because this wasn't a NASA project – funding came from Red Bull, which hired former NASA engineers and astronauts (including Joe Kittinger, who was the man to set the space-diving record in 1960) – Baumgartner's background proved an obstacle in the planning stage, particularly when trying to buy government technology, such as his suit.

"Everyone was saying, 'Felix isn't an astronaut – what the hell does he know?'" Baumgartner says. He certainly trained like one, with hundreds of hours spent in a wind tunnel, one-on-one sessions with Kittinger, and a tough physical regimen that included shadow boxing, kettlebell lifts, and repeated jumps – from 35,000 and 90,000 feet – in the suit. And in the end, he proved that he can land like an astronaut.What was it like when you were falling?
The sky was totally black, and I saw the curvature of the Earth. When you first step out, you have no sensation of speed. No sound. No clouds. I saw the capsule a couple of times when I was rotating. Then I could just see the sky, and then the ground.

What was the scariest part?
When I was spinning, I felt a lot of pressure in my brain and head. I had this button in my hand. If I push that button, it fires the chute and pulls me out of the spin. At the same time, if you fire up that chute, it's all over and you can't break the speed of sound. I had this constant conflict in my mind of "Should I push it and save my life – or am I able to control this?" We all knew I was going to spin. There's no way not to spin. But you control it. You're traveling over 800 miles an hour, so if you stick out your arm too fast, it might become more violent, like a car that's going so fast that you can't use the steering wheel.

What was the most difficult moment for you?
After four hours in the capsule, you're very worn out. You don't have any energy left, but you still have to perform. The whole world is looking at you. Nobody knows what will happen, and you don't know what will happen.

The balloon was 0.0008 inches thick, about the same as a plastic grocery bag. Did you trust it?
In a balloon that big with a human inside, you have to trust the team launching it. If they fuck up, you're dead. ATA Aerospace [which worked on the project] launches a lot of balloons for NASA. It's not difficult in the perfect conditions, but nothing is ever perfect. It might be windy, or conditions can shift unexpectedly – and then the pressure's on.

Did your years as a BASE jumper help prepare you for this?
Yes. For example, difficult BASE jumps require a lot of proper planning. For many of them, you get to the top of a building, but then the wind isn't right and you have to call it off. That's the hardest part. You're right there and you're so close and then you have to turn around. The part I had to train for was the exit from the capsule. At 120,000 feet, the air molecules are so small you have to make the perfect step-off, or you go into a deadly spin. I had to learn the right way to jump out – a bunny-hop that I practiced from a platform on a bungee rope.

During your training, you began to suffer bouts of extreme anxiety.
At a certain point, I found out I couldn't stay in that suit for very long. After an hour I was about to freak out. It was just embarrassing. We had a big test scheduled, and the goal was to stay in the suit for six hours in the capsule, and I knew I couldn't do it. Everyone lost faith in me. I had to fight my fear and make sure my team still believed in me.

What did you do?
I talked to a psychiatrist, and that helped a lot. I had to find a way to overcome my negative thoughts. You can't do this sort of thing thinking negatively. I never really liked the suit. I still don't. You're locked in. You only hear the sound of your breathing. But now I can handle it.

Why did you do this?
I want to inspire the next generation. I would love if four years from now, some young guy calls me up and says, "Mr. Baumgartner, I want to do that."