[Source: CNN]

Walter Cunningham, a retired NASA astronaut and pilot of the first crewed flight in the space agency’s famed Apollo program, died early Tuesday morning at the age of 90, NASA said.

Cunningham was one of the earliest members of NASA’s human spaceflight program as a member of its third astronaut class, joining the space agency in 1963. He was selected to pilot Apollo 7, the first crewed mission of the NASA program that went on to land humans on the moon for the first time.

“We would like to express our immense pride in the life that he lived, and our deep gratitude for the man that he was — a patriot, an explorer, pilot, astronaut, husband, brother, and father,” the Cunningham family noted in a statement shared by NASA. “The world has lost another true hero, and we will miss him dearly.”

The Apollo 7 mission launched in 1968 and lasted roughly 11 days, sending the crew on a journey into orbit that amounted to a test flight that could demonstrate the Apollo capsule’s ability to rendezvous with another spacecraft in orbit and pave the way for future exploration deeper into space. It was also notable for featuring in the first live TV broadcast of Americans from space, according to NASA.

Cunningham was the last surviving member of the Apollo 7 crew, which also included astronauts Wally Schirra and Donn Eisele.

Born in Creston, Iowa, and a recipient of an honors bachelor’s degree in physics and a masters with distinction in physics from the University of California at Los Angeles, Cunningham was 36 years old when the Apollo 7 mission launched. During an interview with NASA’s Oral History Office in 1999, he reflected on his career path and motivations.

“I’m one of those people that never really looked back. I only recall that when someone asked me after I became an astronaut,” Cunningham said. “All I remember is just kind of keeping my nose to the grindstone and wanting to do the best I could as — I didn’t realize at the time, but that was because I always wanted to be better prepared for the next step. I’ve always been looking to the future. I don’t live in the past.”

Though he ventured into outer space only once, Cunningham went on to become a leader in NASA’s Skylab program, the United States’ first space station that orbited Earth from 1973 to 1979.

Before joining NASA, Cunningham enlisted in the US Navy and began training as a pilot in 1952, according to his official NASA biography, and he served as a fighter pilot with the US Marine Corps on 54 missions in Korea.

“The only thing I can ever recall doing specifically to become an astronaut, because I looked at it that I had become one of, if not the best, fighter pilot in the world,” Cunningham said in the interview with NASA’s Oral History Office.

Cunningham also completed a doctorate in physics at UCLA without completing a thesis, and later, in 1974, he completed an advanced management program at the Harvard Graduate School of Business, according to NASA.

He worked as a physicist for the Rand Corporation, a nonprofit military think tank, prior to joining the astronaut corps.

After leaving the space agency, Cunningham wore many hats, taking on various roles in the private sector. According to his NASA biography, he served in a number of executive roles at development companies, worked as a consultant for startups, became an entrepreneur and investor, and, eventually, became a radio talk show host.

In later years, Cunningham also became an outspoken critic of prevailing notions about humanity’s impact climate change.