WASHINGTON: Former U.S. astronaut Walter Cunningham, who flew to space aboard Apollo 7 in 1968 on the inaugural crewed Apollo mission that paved the way for the first human moon landing nine months later, died on Tuesday at age 90, NASA said.

Cunningham joined crewmates Walter Schirra and Donn Eisele for the 11-day mission, which was conducted in low-Earth orbit. It was the first human test flight of the new Apollo spacecraft, which would ultimately land a dozen astronauts on the lunar surface from 1969 and 1972.

He was the last surviving member of the Apollo 7 crew, following the deaths of mission commander Schirra, one of the original "Mercury Seven" astronauts, and command module pilot Eisele, in 2007 and 1987, respectively.

Cunningham was the flight's designated lunar module pilot, even though Apollo 7 did not carry the moon landing craft, and he was responsible for all spacecraft systems except launch and navigation.

Blasting off on Oct. 11, 1968, Apollo 7 marked the resumption of NASA's lunar spaceflight program 21 months after the fire that killed all three members of the Apollo 1 crew - Gus Grissom, Ed White and Roger Chaffee - during a ground-based launch rehearsal in late January 1967.

Prior to his assignment to Apollo 7, Cunningham had been the backup lunar module pilot for the ill-fated Apollo 1 mission, and was on the prime crew for Apollo 2 until it was canceled.

Apollo 7 also was notable for providing the first live television transmission of onboard crew activities, as well as for testy exchanges between ground control and the astronauts, who developed head colds during the flight and openly voiced annoyance with mission directors at times.

Due in part to those tensions, none of the three astronauts went to space again, though Schirra, who by then had flown two previous NASA missions, had already announced plans to retire.

Still, the mission was considered a technical success for proving the capabilities and integrity of systems that would carry Apollo 11 to the lunar surface in July 1969 for the historic first moon walks by astronauts Neil Armstrong and Edwin "Buzz" Aldrin.

Cunningham, who served in the U.S. Navy and Marine Corps, flying 54 missions as a fighter pilot before retiring with the rank of colonel, was selected as an astronaut in 1963 as part of NASA's third astronaut class, the space agency said.

Between his military service and NASA tenure, Cunningham spent three years as a Rand Corp. scientist, working on classified defense studies and problems related to the Earth's magnetic field.

"Walt Cunningham was a fighter pilot, physicist and an entrepreneur – but, above all, he was an explorer," NASA Administrator Bill Nelson said in a statement announcing his death.

Following Apollo 7, Cunningham was assigned to lead the Skylab branch - an early space station program - under NASA's flight crew directorate, and he retired from the space agency in 1971.

He went on to a post-NASA career as an investor and executive in several business ventures, becoming a frequent keynote speaker and radio talk show host.