And, yes, he could break his neck while jumping from a mind-boggling altitude of 23 miles (37 kilometers).
But the risk of a gruesome death has never stopped "Fearless Felix" Baumgartner in all his years of skydiving and skyscraper leaping, and it's not about to now.
Next Monday over New Mexico, he will attempt the highest, fastest free fall in history and try to become the first skydiver to break the sound barrier.
"So many unknowns," Baumgartner says, "but we have solutions to survive."
The 43-year-old former military parachutist from Austria is hoping to reach 690 mph (1,110 kph), or Mach 1, after leaping from his balloon-hoisted capsule over the desert near Roswell.
