GWEN IFILL: Joining me now with an update on the shuttle investigation is David Sanger of the New York Times, he's been covering the "Columbia" disaster. And Jeff Hoffman, a professor of aeronautics and astronautics at the Massachusetts Institute of Technology. He is also a former astronaut, with five space shuttle flights under his belt, including two on the "Columbia." David, we gather today that the independent board that was appointed to oversee the investigation arrived on-site and immediately heard not only Ron Dittemore, the shuttle director but also the Shawn O'Keefe, head of NASA suggesting they were going to reach fewer conclusions like yesterday's about the phone panel and leave that to the board what was going on there?
DAVID SANGER: We're still trying figure out what was gone on but here's what it sounded like. Yesterday you heard Mr. Dittemore, who's been very forthright and out front with us as far as we can tell, All but discount the theory that the foam had hit and damaged the tiles to severely to cause the again the. I think this set off alarm bells within NASA because it had echoes of what happened 17 years ago during the challenger accident which I've also covered and at that time for two weeks NASA basically discounted any of the theories about the O rings, that which of course we later learned caused the accident. And I think they were just concerned it sound as if the team that had done the assessment that said it was safe for the shuttle to come down, was now ratifying their own decision taking something out of the run in this case. Mr. Dittemore came back today and said he didn't mean to do that and of course that theory would be pursued.
GWEN IFILL: David, let's run through some of the outstanding questions still unanswered the question what caused wind drag, air drag over the left wing, what caused temperature spike in the left wheel well, was there any light shed on any of those questions today?
DAVID SANGER: There was not, but we're beginning to see little bits and pieces of evidence that may turn out to be important. These photographs that we're seeing from the West if they turn out to be correct and that's a big if, may show something falling off of the shuttle -- perhaps tiles -- these insulating tiles which have been known to come loose before. And if that's the case, it's possible that thee could fly, that the instruments would not detect any particular drag until the shuttle came down into a heavier part of the atmosphere and then of course trouble began. So it's very possible that things were going wrong that were never detected until that eight minutes before the disaster.
GWEN IFILL: Professor Hoffman you're a member of the very small and exclusive club of men and women who have actually flown on the shuttles. From what you have seen and read so far in the investigation what are the questions which are most nagging at you?
JEFFREY HOFFMAN: Why did it happen? The questions are what everybody is asking. You know, the space shuttle has had successful entries 111 times. When we first launched the "Columbia" back in 1981, there were people had their hearts in their throats until we saw "Columbia" come into the skies over California. But I think people had good confidence and believed that the protection system and reentry works. And it does work -- except in this case. Something was different and we need to find out what. That's what I want to know.
GWEN IFILL: We just heard David compare this investigation to the investigation involving the "Challenger," which you also watched not very close-up but closer than most of us. How do the twin investigations seem to compare at this early stage?
DAVID SANGER: First of all...
GWEN IFILL: I'm really directing the we do professor Hoffman?
DAVID SANGER: I'm sorry.
JEFFREY HOFFMAN: I think that the impression that I have had and the public in general has responded to is that NASA is being very open with the information that's being released to the public and I think thatthat's very appropriate. It's important not only that we find the answers and therefore, are able to fix the problem, but that this be done in an open way that the whole country can have confidence in.
GWEN IFILL: Also, professor, there are 32 missing seconds on the tape which seven searching for a way to figure out what happened in the that portion of the tape they can't quite translate, how important is that?
JEFFREY HOFFMAN: Well, i don't know, because we don't know what's in those 32 seconds. We need to get all of the clues possible. We need to take the "Columbia" as far into its breakup as possible. And at the earth end we want to get as much as information as early as possible in the reentry. And you never know when those critical clues are going to come that will solve the mystery. That's why we need all of the data.
GWEN IFILL: Back to you David on that comparison with the "Challenger" investigation.
DAVID SANGER: I think one of the big differences Gwen in the "Challenger" case weighed lot of evidence early on because it took place after the liftoff segment it exploded only 73 seconds into launch; that's a moment which there are a tremendous number of tracking cameras on the vehicle, a lot of sensor data coming down. In this case, in the "Columbia" case, the breakup occurred when it was at least 40 miles up and very few cameras on it. And for that critical piece of information we're looking at about the liftoff which is whether the foam could have hurt the tiles we heard today from Mr. Dittemore that unfortunately one of the tracking cameras -- the most important one -- was out of focus and, therefore, may not give us good data. So what it tells us is that gathering evidence in this case may be a lot harder than it was in the "Challenger" case.
GWEN IFILL: And David, in your article in the Times today you also suggested they are investigating whether there was an occurrence of space junk which hit the left wing or small meteorite?
DAVID SANGER: There are all kinds of alternative theories out as there were in the "Challenger" case at this stage. Certainly there have been cases of small debris hitting the shuttles in the past during past flights. None of them have ever done any significant damage. But all of those have to be examined, particularly because if we don't believe that the foam was the cause of the damage, then that turns the question of what was. Now, of course today it seems like the foam theory is at least still in the running.
GWEN IFILL: And, David, you have described and so have the folks at NASA something called a fault tree analysis, what is that, assembling all of the information in this investigation?
DAVID SANGER: The fault tree is basically starting with an assumption of all of the possible things that could go wrong and trying to eliminate them one by one system by system and the tree has branches and underneath each system there are many possibilities. Now, this is somewhat controversial -- only because some investigators believe that there are certainly events much higher probability to cause a disaster than others, losing tiles would be one of them. So some people think you should start there and prove certain things didn't happen before you move on to more extraneous theories but it's two different ways of going about it.
GWEN IFILL: Professor Hoffman, as someone who has actually experienced reentry in a shuttle was there any that the astronauts on board would have noticed the irregularity and all of things going on preparing for reentry at a time like that, is there any way to know that?
JEFFREY HOFFMAN: What we found out from the preliminary data, yes, there may have been increased drag on the left side of the shuttle. But the aerodynamic surfaces and the reaction control jets were doing their best to keep the shuttle on its flight path, and so from the point of view of the crew in the cockpit they were gradually feeling gravity return when they came over California they were feeling about four tenths of their normal weight, and by the time they were over Texas they were up to a full one G, of course you feel a lot heavier because he have been in weightlessness before. But it appears in terms of the attitude, the orientation of the shuttle, that it was doing what it was supposed to do but it was apparently working, it had to work a lot harder to do that than it should have been.
GWEN IFILL: Jeff Hoffman and David Sanger, thank you very much for joining us.