NASA says it's going places, that its plan to develop a new space capsule and rocket will take human astronauts places they've never been before - asteroids and eventually Mars. But many former NASA officials are deeply skeptical about the plan espoused by the space agency, at the direction of the Obama administration. Among the critics is the legendary Chris Kraft, NASA's first manned spaceflight director, for whom Mission Control at Johnson Space Center is named. Kraft spoke recently with science writer Eric Berger about NASA's plans. The following are edited excerpts:

Q: I know you've been frustrated with the current direction of NASA. What's the problem with the space agency's plan to build the Space Launch System, a so-called heavy-lift rocket?

A: The problem with the SLS is that it's so big that makes it very expensive. It's very expensive to design, it's very expensive to develop. When they actually begin to develop it, the budget is going to go haywire. They're going to have all kinds of technical and development issues crop up, which will drive the development costs up. Then there are the operating costs of that beast, which will eat NASA alive if they get there. They're not going to be able to fly it more than once a year, if that, because they don't have the budget to do it. So what you've got is a beast of a rocket, that would give you all of this capability, which you can't build because you don't have the money to build it in the first place, and you can't operate it if you had it.

Q: What do you see as the alternative?

A: In the private sector we've got an Atlas and a Delta rocket, and the Europeans have a rocket called the Ariane. The Russians have lots of rockets, which are very reliable, and they get reliable by using them. And that's something the SLS will never have. Never. Because you can't afford to launch it that many times.

Q: So you're saying that NASA should launch its vehicles on existing rockets that can carry less mass into space?

A: What's so magic about this being able to lift 120 tons? Why can't you use what you've got and put your vehicles into space in pieces, like you did with the space station? That's the right way to do it. Eventually you'll get to the point where, even with a really big rocket, you can't put everything on there you need to go where you want to go. Whether you want to go to the moon or Mars, you're going to have to do something in Earth orbit, or maybe lunar orbit, with an assembly capability, a fuel depot capability and the capability to have people operating there sort of as a Cape Canaveral in the sky.

Q: Like a lot of people in Congress, you don't like NASA's plan to attempt landing astronauts on an asteroid before maybe trying to go to Mars in the 2030s. Why?

A: Most in Congress want to see NASA go back to the moon. So do nearly all of the scientific and technical organizations in the world. China said last week they're going to go to the moon. They aren't going just because it's there, it's because it's a place where you want to be from all kinds of points of view, from science, from a resource point of view. There's no reason why you couldn't set up a factory on the moon to build solar panels. You could provide enough electrical power on the moon from solar cells, and eventually you could supply enough power for half the people on Earth with a solar cell farm on the moon. I just think the world is going to use the moon for practical purposes.

Q: A lot of veteran astronauts and engineers are leaving NASA. Why do you think this is?

A: Astronauts want to do something that has some excitement to it. The engineers that come to Johnson Space Center want to do something. You go talk to the guys who were doing Constellation (NASA's now-scuttled plan to return to the moon), and the reason they came to NASA was to go back to the moon. They're all leaving now. The leaders are leaving for a lot of other reasons also, but they're leaving because there's no future that they want to be involved in. And that's unfortunate. You've got to have a reason for people to give you their lives, which is what I did. I gave NASA my life not because they asked me to, but because I wanted to. I had a reason. But I just don't think that's there now.