Austrian daredevil Felix Baumgartner said he was nervous about leaping from a balloon Tuesday nearly 23 miles above Roswell, N.M., but said that\'s a good thing. \"Having been involved in extreme endeavors for so long, I\'ve learned to use my fear to my advantage,\" Baumgartner, a 43-year-old former military parachutist, said in a statement. \"Fear has become a friend of mine,\" he said. \"It\'s what prevents me from stepping too far over the line.\" Baumgartner, who will attempt to break the world record for highest-ever skydive, was expected to lift off in a 55-story helium-filled balloon at 6:57 a.m. MDT, weather permitting. Winds must not exceed 2 mph at liftoff to ensure the balloon -- whose material is 10 times thinner than a plastic sandwich bag -- isn\'t damaged, officials of the Red Bull Stratos mission said. The ascent to 120,000 feet could take up to 3 hours, officials said. The plan is that when he reaches the right altitude, he will jump from a capsule suspended from the balloon and plummet to Earth in a harrowing free fall that will see him become the first skydiver to break the sound barrier. If he does, he would also break a record set in 1960 by Joe Kittinger, who jumped from an open gondola 19.5 miles up but came just shy of breaking the sound barrier. Kittinger -- who is now 84 but was a 32-year-old U.S. Air Force captain at the time -- reached a speed of 614 mph, The (Oklahoma City) Oklahoman reported. Kittinger now serves as a Red Bull Stratos adviser, Space.com said. The mission will be streamed at redbullstratos.com, with a 20-second video delay of the jump in case of a tragic accident. Baumgartner\'s jump is not just for thrills, officials said. Among the mission\'s advisers is Dr. Jonathan Clark, a former NASA flight surgeon whose wife, astronaut Laurel Clark, died in the 2003 space shuttle Columbia disaster. Clark is dedicated to improving astronauts\' chances of survival in a high-altitude disaster, The Oklahoman said. \"Red Bull Stratos is an opportunity to gather information that could contribute to the development of life-saving measures for astronauts and pilots -- and maybe for the space tourists of tomorrow,\" Baumgartner said in his statement. \"Proving that a human can break the speed of sound in the stratosphere and return to Earth would be a step toward creating near-space bailout procedures that currently don\'t exist.\"