The following is a transcript from "FOX News Sunday With Chris Wallace" on July 31, 2005.

CHRIS WALLACE, HOST: Well, it's been quite a ride for NASA and the shuttle this week: first the successful return to space; then those pictures of pieces of foam breaking off the external fuel tank, the same problem that doomed the Shuttle Columbia and that NASA spent the last two and a half years trying to fix.

For an update on the Discovery mission (search), we turn 220 miles into space, where mission commander Eileen Collins and mission specialists Andy Thomas and Charlie Camarda are on board the space shuttle.

Good morning to all of you, and thanks for taking the time to talk with us.

Colonel Collins, how did you first hear that some of the foam from the external fuel tank had fallen off?

SPACE SHUTTLE COMMANDER EILEEN COLLINS: Well, Houston Mission Control (search) called us. They said they were uplinking a message. We have a printer up here. They can send a command. We got the printer.

We were told in the same message that a three-foot piece of foam had fallen off an area of the external tank -- that, by the way, had not been fixed. They told us at the same time that the foam did not hit us. It fell off at a point higher up in the (inaudible) where we think it could have caused damage.

So we never had any fear that there was any problem with our Orbiter Discovery, but we were just surprised that this had happened because we really didn't expect it.

WALLACE: Now, you say that you knew that that part of it had not been fixed. Why not?

COLLINS: Well, I do want to say that I have been following the fixes to the external tank as they went along, and the power ramp was an area that had been sprayed on at a certain way. And as far as we knew, foam could only fall -- the last time foam had fallen off that area of a tank was the second shuttle flight back in 1982. I don't know all the technical rationale, but what I did know, it appeared to me at the time that we were OK not fixing it.

So I am surprised, and I do blame myself for not -- I'm part of this team too, so I want to say that I think the shuttle program made the best decision that they had with the information that they had. But we're learning. We made a mistake in not fixing the power ramp (ph). I'm not going to say we can continue flying this way because we know now that it's something that needs to be fixed.

SPACE SHUTTLE MISSION SPECIALIST CHARLIE CAMARDA: Also, this is the first time we have had so many assets looking at the vehicle, at the launch, in order to understand what is actually coming off the vehicle. So we may not have known other instances where this happened.

This is a very simple structure. It's easy to look at with MDB (ph). And from what we've seen, what the folks on the ground have seen, they did not see any voids (ph). And so we thought that there was a very small chance of this ever happening.

WALLACE: Dr. Camarda, now that you have checked out the shuttle in detail, how confident are you that Discovery is safe to fly back home?

CAMARDA: Well, Andy, Vegas (ph) and myself spent two days looking at the vehicle, inspecting it, both the underbelly of the vehicle and all the orbiter tiles. We looked at the photography. And folks on the ground are analyzing that data.

And from what we have seen, there appears to be very little damage in the tiles. Some small indications that we might have some small, minor hits along the leading edges, which we looked at very carefully with several different laser systems and TV cameras.

And from all indications, it looks like it's a clean vehicle, and we're good to go to return home.

WALLACE: Dr. Thomas, some people here on Earth are saying maybe NASA should have waited until you guys got back home before they announced that they were grounding the shuttle fleet. Did that freak out all of you on the crew at all?

SPACE SHUTTLE MISSION SPECIALIST ANDY THOMAS: No, not at all. In fact, once we got news of the debris coming up the tank and we'd also had some pictures turned up that showed it to us, we were of a single mind up here, I think, that it was necessary to stop flying in order to repair this problem.

That's the correct course of action. That's what you do when you have an incident like this. You look at what is done and take steps to mitigate it and fix it. And if you have to stop flying to do that, that's the right decision. And they told us that, and we agreed with it.

WALLACE: Finally, a question for all of you. There's a lot of talk now here on earth that perhaps they should ground the shuttle fleet permanently and wait to build the next generation of spacecraft.

Beginning with you, Dr. Thomas, do you worry that people here on earth are going to give up on the space shuttle?

THOMAS: Yes, I do worry about that, because the decision to retire a vehicle such as this is based on many factors. And one of the factors you have to consider is what are your commitments, what are you trying to do and (inaudible) exploration.

And if you look at it in that big-picture sense, I think you would agree that it's not yet time to retire the shuttle. It's time to fix it and continue flying and then reassess after the completion of the space station and after the next steps are taken in the development of a subsequent vehicle, the clear (ph) exploration vehicle.

But to do it right now, based on this, would be premature.

CARMARDA: Well, Chris, just to answer that question also, I agree with Andy. We do need return the shuttle back to flying. We will return the shuttle back to flying.

We took a three-pronged approach, and one of those prongs is fixing the tank. And we're doing our best to do that. Debris is coming off the tank, and we're going to minimize that as best we can.

And we'll go back and we'll analyze all the data. Remember, this is an experimental flight. We've collected a lot of data. And now we're going to use that data to compare with our analytical models, our experimental tests and see how those models correlate, and fix the tank.

The other prong of that approach is to basically look at repairing the vehicle if we do have damage. In the unlikely incident we have damage, we've evaluated and the EVAs (ph) yesterday, so we can try several different techniques of repairing tile and also RCC and then making headway in techniques that could potentially repair both the tiles and the RCC.

COLLINS: I'd like to add that there is 2 1/2 million other parts on the space shuttle that are working perfectly right now, and we have confidence in that and we know the shuttle is going to get us home.

I think the shuttle is a fantastic flying machine, and it's done a great job in its lifetime. Eventually it'll be time to retire it though, and we have a plan for that.

WALLACE: I think I speak for everyone when I say that we wish you all the very best of luck. Godspeed, and safe travels back to Earth.

COLLINS: Thank you very much. And thanks for coming on board Space Shuttle Discovery. And thanks for your interest in the space program.

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