The anniversary of the mission was marked Sunday evening at Washington DC's National Air and Space Museum with a lecture and an official ceremony.
At a rare public reunion of the Apollo 11 crew, Buzz Aldrin and Michael Collins said Mars instead of the Moon should be the focus of exploration.
Neil Armstrong, the first man on the Moon, said the race to get to the Moon had been the ultimate peaceful contest.
"It was the ultimate peaceful competition: USA vs USSR. I willll not assert that it was a diversion which prevented a war, nevertheless it was a diversion. Eventually, it provided a mechanism for engendering cooperation between former adversaries. In that sense, among others, it was an exceptional national investment for both sides," Armstrong said.
NASA"s currently stated goal is to return astronauts to the Moon by 2020. But that vision is under review, along with the space vehicles that would get them there.
MSNBS reported, citing anonymous sources, that President Barack Obama will host the Apollo 11 crew on Monday.