"I think that all of us recall the moment in which mankind finally was untethered from this planet and was able to explore the stars; the moment in which we had one of our own step on the moon and leave that imprint that is there to this day," said Mr. Obama, standing beside the three men.
He also struck a personal note.
"I grew up in Hawaii, as many of you know, and I still recall sitting on my grandfather's shoulders when those capsules would land in the middle of the Pacific and they'd get brought back and we'd go out and we'd pretend like they could see us as we were waving at folks coming home," he said. "And I remember waving American flags and my grandfather telling me that the Apollo mission was an example of how Americans can do anything they put their minds to."
pushing hard for the U.S. to send astronauts to Mars, a concept supported by a slim majority of Americans. The president did not touch on a journey to Mars, which his predecessor George W. Bush called for, in his remarks.
Instead, Mr. Obama hailed the potential of the space program to inspire young Americans "who are looking up at the sky and are going to be the next Armstrong, Collins, and Aldrins."
"I think it's very important for us to constantly remember that NASA was not only about feeding our curiosity, that sense of wonder, but also had extraordinary practical applications," he said. "And one of the things that I've committed to doing as president is making sure that math and science are cool again, and that we once again keep the goal by 2020 of having the highest college graduation rates of any country on Earth, especially in the maths and science fields."
The president also said he is "confident" that NASA administrator in Charles Bolden and the deputy administrator Lori Garver "are going to be doing everything that they can in the decade to come to continue the inspirational mission of NASA."
Mr. Obama met privately with Bolden and the Apollo 11 astronauts prior to the appearance.
Complete Coverage: 40th Anniversary of the Moon Landing