The second man to set foot on the moon wants to see NASA send people further into space than he ever traveled. Buzz Aldrin trashed NASA's plan to bring an asteroid into lunar orbit in a speech, advocating for a Mars colony.

Aldrin, who recently published the book "Mission to Mars: My Vision for Space Exploration," said at the Washington, D.C., Humans to Mars summit Wednesday that President Barack Obama's asteroid mining plan is merely a distraction.

"Bringing an asteroid back to Earth? What's that have to do with space exploration?" he asked. "If we were moving outward from there and an asteroid is a good stopping point, then fine. But now it's turned into a whole planetary defense exercise at the cost of our outward exploration."

The Apollo-era astronaut, now 83, has devised a plan to "cycle" spacecraft to Mars, continually launching humans to the red planet to expand on its colony. Aldrin advocates using Phobos, a moon of Mars, as a sort of home base for landing on the planet.

"Going to Mars means permanence, we'd become a two planet species. In Mars, we've been given a wonderful set of moons … where we can send continuous numbers of people," he said. The trips would be one-way.

"Their ultimate destination will be six feet under Mars," he said.

At the same summit, NASA administrator Charles Bolden defended the asteroid deflection mission, saying it was a step toward Mars, which he called "the ultimate destination in our solar system, and a priority for NASA."

That plan calls for NASA to send a robotic mission to a still undetermined asteroid, capture it and return it to lunar orbit. From there, a team of astronauts would be sent to sample the asteroid, sometime in the early 2020s.

"The asteroid and Mars are not either-ors," Bolden said. "The experience of exploring an asteroid will be critical for future Mars journeys."

Aldrin disagrees, saying that the asteroid mission excites no one and is a waste of time.

"It's been 44 years since we stepped on the lunar surface, and I think the progress since then is a little slow. I've always felt that Mars should be the next destination following our landings on the moon," he said. "I want the next generation to feel as we did back when I was privileged enough to be a part of Apollo program."