Answering a question in a Twitter town hall meeting today, President Obama suggested spaceflight is stuck in the Apollo-era mode and said NASA needs a technological breakthrough to allow faster, longer spaceflight with a goal of getting astronauts to Mars.

"Frankly I have been pushing NASA to revamp its vision," Obama said. "The shuttle did some extraordinary work in low orbit: experiments, the International Space Station, moving cargo. It was an extraordinary accomplishment and we're very proud of the work that it did. But now what we need is that next technological breakthrough. [Video: See Obama's Full Comments]

"We’re still using the same models for space travel that we used with the Apollo program, 30, 40 years ago. And so what we've said is: Rather than keep on doing the same thing, let's invest in basic research around new technologies that can get us places faster, allow human spaceflight to last longer. And what you're seeing now is NASA, I think, redefining its mission.

"We've set a goal: Let's ultimately get to Mars," the president said while fielding questions from Twitter users about the economy and other subjects. "A good pit stop is an asteroid." He joked that a specific asteroid has not been chosen.

Obama was clear in alluding to what some critics have said: NASA's human spaceflight program has been stuck flying circles around Earth for decades. [What Obama and Congress Should Do for Spaceflight and Exploration]

"Let's start stretching the boundaries so we’re not doing the same thing over and over again," he said. "Rather, let’s start thinking about what’s the next horizon? What’s the next frontier out there? But in order to do that, we’re actually going to need some technological breakthroughs that we don't have yet."

The president did not dismiss low-Earth orbit efforts, but put that responsibility on the shoulders of private enterprise. Let the private sector handle routine tasks of sending vehicles into Earth orbit, he said.

And he mentioned how that could, in time, lead to space tourism:

"We may be able to achieve a point in time where — those of you who are just dying to go into space — you can buy a ticket and a private carrier can potentially take you up there while the government focuses on the big breakthroughs that require much more larger investments and involve much greater risk."

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