Walter Cunningham, Who Helped Pave the Way to the Moon, Dies at 90

NASA upgraded the Apollo 7 astronauts’ medals to the Distinguished Service citation at an October 2008 ceremony, citing the mission’s success, notwithstanding the arguments with flight controllers. But Mr. Cunningham was the only crewman alive by then. Major Eisele, who died in 1987, was represented by his widow, Susan Eisele-Black; Captain Schirra, who died in 2007, by the astronaut Bill Anders.

Mr. Kraft struck a conciliatory stance. “We gave you a hard time once, but you certainly survived that and have done extremely well since,” he told Mr. Cunningham in a recorded message. “You’ve done well by yourself, you’ve done well for NASA, and I am frankly very proud to call you a friend.”

Ronnie Walter Cunningham was born on March 16, 1932, in Creston, Iowa, the eldest of five children. His father, Walter, had a small construction business. When he was young, his family moved to Venice, Calif.

He entered the Navy in 1951 and flew Marine Corps jets. After leaving active service in 1956, he received a bachelor’s degree and a master’s in physics from the University of California, Los Angeles. While at the RAND Institute in October 1963, pursuing doctorate-level studies, he was named to NASA’s third group of astronauts.

Soon after Apollo 7, Mr. Cunningham was named director of what became known as the Skylab program, which developed America’s first space station. The astronaut Pete Conrad succeeded him in 1970. Mr. Cunningham resigned from NASA the next year after failing to get an assignment to fly in Skylab’s forthcoming missions.

Mr. Cunningham later became a senior executive at financial and real estate companies. In 2012, he joined with a group of former astronauts and NASA employees who sent a letter to the agency criticizing what they felt were its unproven assertions that man-made carbon dioxide was a major factor in global warming.