One of the first astronauts to orbit the Moon said on Wednesday that it's "stupid" to plan human missions to Mars.
Bill Anders, who was the lunar module pilot for NASA's Apollo 8 mission, told BBC Radio 5 Live that sending crews to the Red Planet would be "almost ridiculous."
The U.S. space agency's goals include sending humans to Mars for exploration and scientific study.
"What's the imperative? What's pushing us to go to Mars?" Anders, 85, said, adding: "I don't think the public is that interested."
Still, the retired astronaut did explain that he's a big supporter of NASA's unmanned programs to Mars — "mainly because they're much cheaper."
In a statement, NASA told the BBC that it was "leading a sustainable return to the Moon, which will help prepare us to send astronauts to Mars."
"That also includes commercial and international partners to expand human presence in space and bring back new knowledge and opportunities," the statement said.
Although Anders was part of the December 1968 crew that was the first manned spacecraft to leave low Earth orbit, get to the Moon and return, he has some scathing words for what NASA has become in the decades since that historic voyage.
"NASA couldn't get to the Moon today," Anders told BBC Radio 5 Live. "They're so ossified... NASA has turned into a jobs program... many of the centers are mainly interested in keeping busy and you don't see the public support other than they get the workers their pay and their congressmen get re-elected."
Anders former crewmate, Frank Borman, was also interviewed about the space agency.
"I'm not as critical of NASA as Bill is," Borman told 5 Live. "I firmly believe that we need robust exploration of our Solar System and I think man is part of that."
Still, when Borman was asked about the plans of SpaceX founder Elon Musk and Blue Origins founder Jeff Bezos, he said that talk of putting colonies on Mars is "nonsense."
Anders and Borman spoke to BBC Radio 5 Live as part of a special documentary on the 50th anniversary of the historic lunar mission.