Orlando, Fla. - When Robert White shot through the sky in a rocket-powered X-15 airplane nearly 50 years ago, he earned a place in the development of America's space program that those in the field still talk about.

First to break Mach 4 - four times the speed of sound. First to break Mach 5. First to break Mach 6 - more than 4,000 miles per hour. All in a few short months in 1961.

Then in 1962 the young test pilot with Hollywood good looks nosed his airplane 59 miles above the earth to be the first to take a winged craft into space.

"He is an icon," said Jim Young, chief historian at Edwards Air Force Base in California. "He accomplished some things that were major milestones in the history of flight."

White, of Orlando, who retired from the Air Force in 1981 as a major general, died in his sleep Wednesday after several months of declining health. He was 85. Greg White, his son, remarked that it was ironic that a man who lived his life on the edge of danger for decades died so peacefully.

Father and son appeared on the cover of Life magazine in 1962 under the title "What a Ride!" after White's landmark journey into space. It was the apex of his career as a test pilot, the nation was enthralled, and kids across America were busy gluing together gray plastic models of his plane.

While first American astronauts Alan Shepard, Virgil Grissom and John Glenn all had been nose-coned into space at the time, White's feat was a forerunner of the space shuttle program to follow years later.

White was a member of a select group of test pilots at Edwards in the 1950s and early 1960s who pushed the limits of developmental aircraft. After the rocket-powered X-15 came on line, he was designated as its chief test pilot.

Born and raised in New York City, he entered the military in 1942 as an aviation cadet and was commissioned as a pilot in 1944 in the thick of World War II. His P-51 aircraft was shot down over Germany in early 1945, and he spent a couple of months in a prisoner of war camp before being liberated.

After the war, White left the service and went to college at New York University and earned a degree in electrical engineering. He was called back into the service during the Korean War and had stints at bases in New York state and Japan.

In 1954, White was transferred to Edwards, where the testing toward space flight was getting under way. He was part of the pioneering group detailed in writer Tom Wolfe's novel and subsequent movie "The Right Stuff" about the early development of the space program.

After his speed and space feats in the early '60s, White also served in Germany and in the Vietnam War, where he completed 70 combat missions in an F-105. He later had several stateside assignments before retiring. He was inducted into the National Aviation Hall of Fame in 2006.

"Clearly, his contributions are incredibly significant in the development of the Air Force," said Andrew Bourland, spokesman for the Air Force. "He really helped set the standard for the level of technology that we were able to incorporate in future aircraft."

Although the test pilots were sometimes described as "cowboys," White was anything but a daredevil, those who knew or studied him say.

In "The Right Stuff," Wolfe describes White as "slender, black haired, handsome, intelligent - even cultivated, if the truth were known. And he was not a beer-call fighter jock. He didn't drink. He exercised like a college athlete in training. He was religious."

White achieved because he was highly disciplined, precise and incredibly organized, his son said. Being a devout Catholic added to his father's strength, he said.

"He was an American hero," he said.

In addition to son Greg of Orlando, White also is survived by son Dennis White of Sarasota, Fla., and daughters Pam White and Maureen McFillen of Birmingham, Ala., and four grandchildren.