Astronaut Gordon "Gordo" Cooper, a veteran of NASA's Mercury and Gemini programs that paved the way for the Apollo moon landings, died today at his home in Ventura, Calif. He was 77 and his death came 47 years to the day after the space age began with the launch of the Russian Sputnik satellite.

Gordon "Gordo" Cooper was one of NASA's original astronauts. Photo: NASA

"As one of the original seven Mercury astronauts, Gordon Cooper was one of the faces of America's fledgling space program," NASA Administrator Sean O'Keefe said in a statement. "He truly portrayed the right stuff, and he helped gain the backing and enthusiasm of the American public, so critical for the spirit of exploration. My thoughts and prayers are with Gordon's family during this difficult time."

Former U.S. Senator John Glenn said, "Gordo's final launch came as a shock, because the last time Annie and I were with him, his health seemed to have improved. There are thousands of memories from our early space days. Gordo was one of the most straightforward people I have ever known. What you saw was what you got. Pride in doing a great job, whatever his assignment, was his hallmark. You could always depend on Gordo. It's hard to believe that he will no longer be with us in person. I know he'll be with us in spirit. Our thoughts and prayers are with his wife Suzie and his family."

Known as a natural "stick and rudder man," Cooper was the youngest of the Mercury Seven, selected along with Alan Shepard, John Glenn, Donald "Deke" Slayton, Scott Carpenter, Gus Grissom and Walter Schirra as America's first set of astronauts.

"We seven were bonded like brothers, maybe even closer if that's possible," Walter "Wally" Schirra said today. "Gordon backed me up on my Mercury flight which went very well. In turn, I backed him on his flight, which went equally as well. He now has joined Gemini crewmate, the late Pete Conrad, in orbit."

"This is truly the passing of a beloved member of a unique fraternity. We'll all miss him," Scott Carpenter said.

Cooper blasted off in his Faith 7 capsule atop an Atlas rocket on May 15, 1963, completing 22 orbits and becoming the first American to sleep in orbit before returning to Earth the next day.

"Cooper's efforts and those of his fellow Mercury astronauts, Alan Shepard, Gus Grissom, John Glenn, Scott Carpenter, Wally Schirra and Deke Slayton, serve as reminders of what drives us to explore," O'Keefe said. "They also remind us that to succeed any vision for exploration needs the support of the American people."

Of the original Mercury 7, Grissom was killed in an Apollo launch pad fire in January 1967. Slayton and Shepard, like Cooper, died earlier of natural causes.

Cooper joined Charles Conrad Jr. for his second space flight, an eight-day mission aboard a two-man Gemini capsule in August 1965 that was designed to confirm astronauts could survive in space long enough to reach and return from the moon.

Gordon's Gemini capsule launches aboard a Titan 2 rocket. Credit: NASA

Despite numerous technical glitches, the two astronauts completed a 191-hour, 122-orbit mission that included a make-believe rendezvous to test the techniques that would be needed during the Apollo program.

Cooper's efforts and those of his fellow Mercury astronauts ... serve as reminders of what drives us to explore," O'Keefe said. "They also remind us that to succeed any vision for exploration needs the support of the American people."

Leroy Gordon Cooper Jr. was born March 6, 1927, in Shawnee, Ok. He earned a bachelor of science degree in Aeronautical engineering from the Air Force Institute of Technology in 1956 and later received an honorary doctorate of science degree from Oklahoma City University in 1967.

Cooper received an Army commission after three years at the University of Hawaii, but he transferred his commission to the Air Force and began flight training in 1949. He flew F-84 and F-86 jets while stationed in Germany.

After earning his degree, he was selected for training at the Air Force test pilot school at Edwards Air Force Base, Calif. The sprawling base is just a few miles from the Mojave Airport where pilot Brian Binnie became the second private-sector astronaut earlier today with a flight that mirrored, in some ways, the early Mercury missions.

He was selected as a Mercury astronaut in April 1959, becoming an instant celebrity in the space race with the former Soviet Union. Along with his two space flights, Cooper served as backup commander for Gemini 12 and the Apollo 10 mission that preceded the first landing on the moon in 1969. He retired from the Air Force and NASA in 1970.

That same year, he founded Gordon Cooper and Associates, a consulting firm specializing in a wide variety of commercial enterprises. In 1975, he joined Walter E. Disney Enterprises Inc. as vice president of research and development.

He held a variety of other positions in the private sector and served as an on-air consultant for CBS News during Glenn's launch aboard the space shuttle Discovery in October 1998.

Cooper listed his hobbies as treasure hunting, archeology, racing, flying and outdoor sports. He was a member of the Society of Experimental Test Pilots, the American Institute of Aeronautics and Astronautics, the American Astronautical Society and many others. His honors and awards include the Air Force Legion of Merit, the Air Force Distinguished Flying Cross, the Air Force Distinguished Flying Cross Cluster and the NASA Exceptional Service Medal.

He also held the Ivan E. Kincheloe Trophy, the Collier Trophy and a variety of other aerospace honors.