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Gehman: NASA is meeting intent of Columbia board
Posted: February 10, 2005

The chairman of the Columbia Accident Investigation Board believes NASA has made a credible attempt to meet the spirit and intent of the board's return-to-flight recommendations, even though the agency will not have certified tile or wing leading edge repair techniques in place before Discovery blasts off in May.

The Columbia Accident Investigation Board was led by Harold Gehman, a retired admiral. Photo: NASA TV
NASA managers, engineers and astronauts at the Johnson Space Center in Houston, meanwhile, are meeting today to discuss what, if any, repair techniques to actually test during Discovery's mission. Sources familiar with the ongoing debate say additional time is needed to perfect more ambitious repair procedures and that Discovery's crew may be limited to testing relatively simple techniques for fixing relatively minor damage.

Even so, Harold Gehman, the retired admiral who chaired the independent panel that investigated the Columbia disaster, said he has no objections to NASA's plan to resume shuttle flights in May while testing and analyses continue. But Gehman said that does not mean NASA can ever give up trying to perfect repair techniques, or worse, stop listening to the concerns of the agency's engineering community when problems arise.

In a telephone interview Wednesday with CBS Space Consultant William Harwood, Gehman discussed his impressions of NASA's recovery from the 2003 Columbia disaster and the intentions behind the CAIB's recommendations.

Q: Have you been following NASA return to flight efforts? And do you think NASA is meeting the intent of your recommendations?

Gehman: One of the things the CAIB said when we released our report, and we've said it consistently since, we were not going to be sitting on the sidelines doing what we called 'grading NASA's papers.' So we have been following, and I have been following, loosely and from a distance, the return to flight efforts and the function of the return to flight task group, the Stafford-Covey group.

[The Return to Flight Task Group, chaired by former Apollo astronaut Thomas Stafford and veteran shuttle commander Richard Covey, is providing an independent assessment of NASA's implementation of the CAIB's recommendations.]

Gehman: So I've been following this business, but not in great detail because our policy was that unless they just gaff us off, we weren't going to critique them. And they certainly are not gaffing off our recommendations. They certainly are making a try.

Our intent was, and I think that we said this in the report and I could quote you the page, what we wanted to do was break what we considered a very rigid, or tightly coupled, chain of events that starts with debris and ends with losing astronauts. It's a chain of events and what you need to do to ensure, or maximize the safety of the astronauts, is to do everything you can to strengthen every link in the chain. Or, if you look at it the other way around, if it's a chain of events that leads to an untoward incident, then break the chain and break it in as many places as possible.

All you've got to do is break the chain of tightly coupled events, which leads to the loss of an astronaut. Where you break it in the chain doesn't make any difference. So what we said was, you've got to do essentially four things in order to break this closely coupled chain of events.

First of all, you've got to understand foam creation and the creation of the hazard in the first place and you've got to do everything you can to prevent the creation of foam (debris) in the second place. The second thing you've got to do is, you've got to have much better pictures on launch and ascent to know whether or not there's been a foam event, or a debris event. You've got to know that. The third thing you've got to do is, you've got to essentially re-certify the orbiter to be ready to come back into the Earth's atmosphere. That translates into some kind of an inspection in orbit. And we didn't specify what kind of an inspection, (just that) you've got to be able to inspect it to see if there's anything wrong with it.

[In an aside, Gehman said the board was "quite struck by the first law of thermodynamics. I mean all the energy that goes into putting this thing into orbit, every single BTU of energy has got to come back out of it again. It's much more dramatic taking off than it is coming back to Earth, but that's only because we're standing there listening to the thunder and watching the light. But the coming back is just as exciting. So they go to all (this trouble) to certify the thing to take off and then they kind of gaff off the coming back in part. We were kind of struck by that."]

Gehman: And then, if you do have something wrong with the orbiter, you have to have some minimal, practical kind of capability to do some kind or orbital repair, the best practicable kind of a repair. Knowing full well, depending on the size of the damage or what the nature of the damage was, there are some repairs that are beyond your capability to do in space. And it has been our unwritten policy (that) you must attack all four of these things.

Now, you can do some better than others. If you really think you've done a fabulous job of preventing the creation of debris in the first place, you've got some really good ways to take pictures to make sure your orbiter hasn't been struck or anything like that and you're really sure that it's in good condition, then you can do some of the other stuff to a lesser degree. But you do have to make an attempt at all four areas. Now, within those four areas, there are sometimes one, two, three or four things that you've got to do. But that was what our intent was.

Q: NASA managers clearly believe they have reduced foam shedding to a minimal, reasonable level. They believe nothing much larger than 0.03 pounds can come off a section of the tank high enough up the stack to possibly hit a wing leading edge or any other critical structure. Are you comfortable with that?

Gehman: Not only have they minimized the foam but as I said, there are two or three sub bullets under each one of those things. One is, at least the people we talked to (during the investigation), they didn't have an understanding of the true strength of RCC. So they've been testing RCC to see how strong it really is, how big a piece of debris is dangerous and all that kind of stuff. And of course, the big picture, the big problem with the debris assessment team in the case of Columbia, was they had these crummy photographs and couldn't tell whether or not the thing was really a hazard or not. Well, we want them to be able to judge whether they've got a hazard or not. So, they really have taken us to heart on all those things.

[NASA will use high-definition television cameras attached to large telescopes to augment high-speed film and movie cameras to fully document launch and the initial climb toward orbit. Cameras on the external tank, the solid-fuel boosters and in the belly of the shuttle itself will look for signs of foam shedding, as will two camera-equipped WB-57 jets flying offshore. Impact sensors behind the wing leading edge panels will record - and pinpoint - any real debris strikes. In addition, the astronauts will photograph the tank after it separates from Discovery and use cameras and laser sensors on the end of a long boom to inspect both wing leading edges and the shuttle's carbon composite nose cap on the second day of the mission. Finally, the crew of the international space station will photograph the belly of the shuttle during the ship's final approach on flight day three to look for signs of tile damage. Additional inspections are planned later in the flight.]

Q: With improved imagery and wing leading edge sensors, engineers believe they will know if there's any sort of impact damage. They've minimized foam shedding and in a worst-case scenario, the crew could use the station as a safe haven while awaiting rescue. The real issue comes down to whether that's enough and whether it's safe to go fly without a certified repair technique. They will not have one by the time they fly.

Gehman: We understand that and it is our judgment that they're efforts have passed the criteria that we set up for them.

Q: So you think it's a reasonable thing to go fly without a certified repair technique given everything else they've done.

Gehman: That's correct. But that doesn't mean they're allowed to give up on the repair. In our view, they have to keep working at it. And of course, we're talking about our 15 return-to-flight things (recommendations). Remember, there are 14 other recommendations, all of which they've got to work on. And they are. They are. Now that's not to say that some NASA engineer who's working on some subsystem deep down inside may feel that his box is not checked. There probably are some engineers who say, 'wait a minute, we're still working on this camera thing or the boom thing and it's not ready.' And he's probably right. So don't take my words as necessarily being construed that NASA engineers with subsystem problems don't need to be listened to.

Q: The perception seems to be that the CAIB told NASA to develop repair techniques and that, if NASA doesn't have them, the agency is not meeting the intent of the CAIB.

Gehman: Right. And we had no idea we were being prescient when we did this, but we worded that recommendation as broadly and as loosely as we possibly could, just to make sure that we did not box either ourselves or NASA in.

Q: Are you surprised it's taken this long to develop repair procedures and return to flight?

Gehman: "Yeah. Some of it is our fault in that something as simple as putting a camera on the belly (of the shuttle), when you really go through certifying it for spaceflight it turns out to be a pretty large step. It's not just a matter of buying a camera, getting some rivets and screwing it on. Turns out, the steps that they go through to make sure everything is done right - and now, of course, they're being really scrupulous about it - it does take longer. We probably underestimated it. But we didn't think each of our recommendations by themselves, except for maybe on-orbit repair, actually were not very difficult. We did say in our press conference, though, that when you add them all up it might be a pretty tall hill. So yes, I must admit I thought this would get done in a year. But that's just my layman's voice speaking.

Q: In a hearing after the CAIB report was released, you were asked about coming back and taking a look at NASA's progress. Has anyone asked you to actually do that?

Gehman: Let me make sure you and I are on the same page here. The question was culture. How do you know if the culture has really changed? It wasn't a question about certification for flight, return to flight or anything like that. The question was, how would you know the culture has really changed? And I foolishly replied that we would know, we could tell in a week or two because we know exactly where to go and exactly what questions to ask. And they said well, would you be interested in coming back in a year to see whether or not the culture has changed? Culture was the issue. As a matter of fact - I had already cleared this with the board - I said 'if directed, we will serve.' In other words, we aren't volunteering. But so far, the Congress has not asked.

Q: Does the difficulty of coming up with a repair imply anything about the overall worthiness or safety of the shuttle? Recent impact tests show even coating damage to a reinforced carbon carbon (RCC) wing leading edge panel can be entry critical.

Gehman: I'll tell you what it says to me. It says to me that the organizational changes that we prescribed are more needed than ever. In other words, this kind of testing and this kind of awareness should have been known 15 years ago, or 20 years ago. When we probed into what is RCC, how strong is it, what are the specs and all that kind of stuff, they did not demonstrate a lot of detailed knowledge and they had not been testing or examining. ... So what it indicates to me is that the independence of the engineering department, independently funded, to be able to continuously test and continuously examine the specifications and requirements to see that they're right and that they're adhered to is just very important.

I understand what their testing has found and things like that, but you've got to remember that shuttles have returned safely with small delaminations and things like that. So you know, I'm pleased that they're learning more about RCC and I'm pleased that they're more nervous about it. But it doesn't strike me as changing the air worthiness of the vehicle. That's not the way I take it.

Q: So to reiterate, given your knowledge of all this, you think it's reasonable to go fly in May?

Gehman: Yes. As far as the CAIB is concerned, we think they have fulfilled their requirements and that they are diligently working on all the things we asked them to, to the degree that once it passes their internal return to flight certification, we think that they've done their job.

Q: Do you and the other board members still keep in touch?

Gehman: Yes, all the time. We're very active emailers to each other, it became a very close group. We speak at each other's seminars and things like that, see each other on a regular basis.

Q: Do you think your report will stand the test of time?

Gehman: So far, I've been invited on speaking tours at many universities and colleges and places like the nuclear power industry and other risky kinds of things, and they all say 'you're report is textbook, that's what we use for teaching and risk assessment.'

Q: One final question. Can the culture change the CAIB kicked off be too much of a good thing? Giving everyone a voice means it takes a long time to reach a consensus.

Gehman: Right. I know. They're going to have to sort they're way through that. As we indicated in our report, we went around and looked for best practices in other enterprises which are highly risky, like the Navy submarine program. And they have the same issue and they've learned mechanisms for how to deal with that. What NASA needs to do is they need to learn how to deal with those things. But suppressing the engineers isn't one of them.

Q: Are you coming to Discovery's launch in May?

Gehman: If I get invited.