ROSWELL, N.M. — A well-known computer scientist parachuted from a balloon near the top of the stratosphere on Friday, falling faster than the speed of sound and breaking the world altitude record set just two years ago.
The jump was made by Alan Eustace, 57, a senior vice president of Google. At dawn he was lifted from an abandoned runway at the airport here by a balloon filled with 35,000 cubic feet of helium.
For a little over two hours, the balloon ascended at speeds up to 1,600 feet per minute to an altitude of more than 25 miles. Mr. Eustace dangled underneath in a specially designed spacesuit with an elaborate life-support system. He returned to earth just 15 minutes after starting his fall.
“It was amazing,” he said. “It was beautiful. You could see the darkness of space and you could see the layers of atmosphere, which I had never seen before.”
Mr. Eustace cut himself loose from the balloon with the aid of a small explosive device and plummeted toward the earth at speeds that peaked at 822 miles per hour, setting off a small sonic boom heard by observers on the ground.
“It was a wild, wild ride,” he said. “I hugged on to the equipment module and tucked my legs and I held my heading.”
He did not feel or hear the boom as he passed the speed of sound, he said. He performed two slow backflips before a small parachute righted him.
His technical team had designed a carbon-fiber attachment that kept him from becoming entangled in the main parachute before it opened. About four-and-a-half minutes into his flight, he opened the main parachute and glided to a landing 70 miles from the launch site.
“To break an aviation record is incredibly significant,” said Mark Kelly, the former astronaut, who viewed Mr. Eustace’s ascent. “There is an incredible amount of risk. To do it safely is a testament to the people involved.”
Mr. Eustace’s maximum altitude was initially reported as 135,908 feet. Based on information from two data loggers, the final number being submitted to the World Air Sports Federation is 135,890 feet.
The previous altitude record was set by Austrian daredevil Felix Baumgartner, who jumped from 128,100 feet on Oct. 14, 2012.
Mr. Eustace was carried aloft without the aid of the sophisticated capsule used by Mr. Baumgartner or millions of dollars in sponsorship money. Instead, Mr. Eustace planned his jump in secrecy, working for almost three years with a small group of technologists skilled in spacesuit design, life-support systems, and parachute and balloon technology.
He carried modest GoPro cameras aloft, connected to his ground-control center by an off-the-shelf radio.
Although Mr. Baumgartner was widely known for death-defying feats, Mr. Eustace describes himself as an engineer first with a deep commitment to teamwork. He pilots his own Cessna twin-engine jet and has a reputation in Silicon Valley for thrill-seeking.
“Alan is a risk-taker with a passion for details,” said Brian Reid, a computer network specialist who has worked with Mr. Eustace.
After he decided to pursue the project in 2011, Mr. Eustace was introduced to Taber MacCallum, one of the founding members of the Biosphere 2 project, an artificial closed ecosystem built to explore concepts such as space colonization. Mr. Eustace had decided to pursue a simpler approach than Mr. Baumgartner’s.
He asked Mr. MacCallum’s company, Paragon Space Development Corporation, to create a life-support system to make it possible for him to breathe pure oxygen in a pressure suit during his ascent and fall.
Mr. Eustace said Google had been willing to help with the project, but he declined company support, worried that his jump would become a marketing event.
James Hayhurst, director of competition at the United States Parachute Association, who verified the record, described the venture as “legitimate science.”
“I think they’re putting a little lookout tower at the edge of space that the common man can share,” he said.
Mr. Eustace said he gained a love of space and spaceflight while growing up in Orlando, Fla., during the 1960s and 1970s. His family crowded into a station wagon to watch every launch from Cape Canaveral (known as Cape Kennedy during some of that time). A veteran aircraft pilot and parachutist, he worked as a computer hardware designer at Digital Equipment Corporation for 15 years before moving to Google in 2002.
Mr. Eustace said that his technical team designed and redesigned many of the components of his parachute and life-support system during the three-year development phase. Many of the redesigns were the result of technical surprises.
For example, he discovered that in order to control his suit, he was required to make movements that were exactly the opposite of the control motions made by a conventional parachutist. Left movements must be made for rightward motion, for instance, and upward movements for downward motion.
The stratosphere becomes warmer at higher elevations, and the suit designers had to figure out how to keep Mr. Eustace sufficiently cool at the top of the stratosphere, because there is no atmosphere to remove the heat. His suit did not have a cooling system, so it was necessary to make elaborate design modifications to keep dry air in his helmet so that his face plate did not fog.
In order to keep from overheating, Mr. Eustace kept his motions to a minimum during his ascent, including avoiding moving his arm to toggle a radio microphone. Instead, he responded to ground controllers watching him from a camera rigged above his suit by slightly moving one leg to acknowledge their communications.