NASA Bans Future Shuttle Flights

NASA: No Flights Until Foam Issue Fixed

Only days after the launch of the space shuttle Discovery, NASA has grounded all of its shuttle flights until a problem with foam debris is addressed. During liftoff, a thick chunk of foam broke away from the fuel tank. And although there is no apparent damage to the shuttle, it was a similar issue with debris that led to the Columbia disaster. What does this mean for the Discovery's current mission and for future NASA shuttle flights?

Dr. Roger Launius , chair of the Division of Space History at the Smithsonian's National Air and Space Museum, was online Thursday, July 28, at 11 a.m. ET to discuss NASA's grounding of its shuttle fleet.

Read the story:

NASA to Ground Shuttles Again (Post, July 28)

A transcript follows.

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Roger Launius: Hello everybody. It's a pleasure to be with you in this online chat and I look forward to speaking with you about the questions you have.

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Rochester, N.Y.: What's the likelihood that this might end the Shuttle program early since it's already supposed to end in only 5 years?

Roger Launius: Obviously there are new questions about whether we should continue to fly the shuttle because of the external tank and the foam insulation that was falling off it. Some people say we should probably retire the fleet now and then use the funding for shuttle build the Crew Exploration Vehicle (CEV). There are others who believe it is critical to fulfill our international commitments with our partners on the international space station. The only way to do that is to continue to fly the shuttle until the station is completed.

What may actually end up happening out of this, obviously, remains to be seen. There is room for a serious policy debate with well-meaning people from each side disagreeing on whether to retire the shuttle or not. With the foam insulation problem that has not been resolved despite 30 months of work, those who suggest that we move on to the CEV may have the upper hand in the debate.

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Wuhan, China: Are you sure the Discovery space shuttle will come back to the Earth?How can you ensure the crew's safety?

Roger Launius: Nothing is 100 percent guaranteed. And we don't know yet the extent of any damage that might have taken place with the orbiter. The preliminary analysis suggests that there was almost no damage to the vehicle. There will be additional pictures and video and those will be analyzed in detail and only then will we have any sense of whether or not Discovery will be able to come home safely.

I'm quite optimistic that this crew will return safely.

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Washington, D.C.: Hi Dr. Launius, Do you think it's prudent to pay so much attention to launch debris? The shuttle program has gone on for decades with little trouble attributed to this one type of problem. Aren't there other problems that could now "sneak up" on NASA because everyone is paying so much attention to handling debris?

Roger Launius: Clearly there are many, many possibilities for failures of the shuttle. Everyone is heavily focused on the external tank foam debris because of its centrality to the loss of Columbia. The question in my mind is are we seeing something with the numerous debris coming off of the external tank that has always taken place but now we actually have cameras to view it? Or are we seeing something unique?

If this is something that we are simply documenting ion detail for the first time and its something that's been taking place throughout the history of the program it's important but it might be less significant than some other issues that we're missing because we're so focused on this one.

If it is a unique experience that's happened of late doing in Columbia and now having these anomalies, the question we should ask is what has changed to lead to all of this debris and how do we go about correcting it. There are serious concerns about this problem and it not being fixed despite 30 months of work on it. That is the reason that there's such a focus on it at this point in time. But no question, there are many other components of the technology that have to be watched as well.

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Washington, D.C.: Politically speaking, do you think that it was a terrible idea to go ahead with the flight with all of the talk of the fuel gauge problems? I realize that NASA states that this wasn't a huge issue in terms of the safety of the shuttle launch, but in political terms it seems to be a bad move as NASA's public support has waned so much over the years.

Roger Launius: There are all kinds of reasons that any engineer can find in any piece of technology as complex as the space shuttle that would put a mission at risk. If an engineer had always stopped flying every time they had a doubt about one of the components they would never fly. So from an engineering perspective they have to balance that risk against all of the other parameters of the program, be they technical or political. In this particular case, the NASA administrator made the decision to launch accepting the risk of the sensors. He had good reason to believe there would not be a problem, but not 100 percent certainty.

Politically, NASA will have to deal with the fallout from the sensor problem and the two-week delay but even more so the external tank debris issue where they had spent an enormous amount of effort and did not resolve the problem yet chose to fly anyway.

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Manchester, Tenn.: What was done differently with the insulation on the Discovery's tank to avoid a recurrence of falling insulation like what caused the Columbia disaster?

Roger Launius: There were a series of efforts undertaken to resolve the external tank foam insulation problem. First and foremost, they changed the method of adhering it to the external tank. Second, they removed foam from the bipod ramp which is the point where the foam had come off and struck the Columbia on launch. They also re-engineered certain parts of the placement of the foam on the external tank in the hopes of making it more aerodynamic and structurally sound.

Finally, the procedures for building the external tank were reviewed and changed to ensure the best possible tank emerged from the production facility. Unfortunately it appears that none of these fully resolved the problem.

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Arlington, Va.: Maybe this is an urban legend but I heard that NASA replaced the protectant foam several missions before the Columbia with more environmentally friendly foam that is now causing the problems. Is this true?

Roger Launius: There have been several changes to the chemical ingredients of the foam over the years. There's no particular reason that the latest of those changes in any way caused or contributed to the insulation debris problem. Over the years whenever they've changed the formula for the foam they have sought to make it less toxic, more environmentally friendly, easier to handle, easier to apply, more resilient and more effective in terms of insulating the spacecraft.

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Merritt Island, Fla.: If the shuttle cannot fly and provide logistical support to the International Space Station, should it be turned over to another space faring country?

Roger Launius: Well, that's a really interesting question.

It begs a whole series of questions that follow from that. The first is, would the U.S. be willing as a nation to donate the shuttle to another entity? Would another nation be interested in taking on this responsibility? Would the private sector have a role in any of this?

To my knowledge, this issue has not been considered by anyone in political circles.

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Denver, Colo.: The space shuttle was originally promoted as a means to make space travel routine in comparison with Apollo. In these terms, it was sold primarily on economic, not technical benefits. From the standpoint of technical performance (upmass, mission duration, and orbital repair for example), the Shuttle has met its objectives. From a reliability, risk and cost standpoint it can be seen only as an economic failure.

Do you think the design of the next manned space system (CEV) would benefit more from better engineers or better economists?

Roger Launius: No question, the shuttle was oversold as a space truck that would make access to space routine and affordable. NASA failed to understand in the 1970's and only really learned the lesson in the aftermath of Challenger that the vehicle is experimental, that it obviously had some important capabilities that did not exist previously, but that its promise of low-cost, safe, routine space access would not be achieved. Failure to achieve that rests with several communities of people. First it rests with the engineers who believe that they could satisfy the requirement. At some level a certain hubris reigned. After all, these were the engineers who put America on the moon. They truly believed that they could do this.

It also rests with the economist who crunched the numbers that said that if you flew the shuttle 50 times a year it would pay for itself through amortization. Imagine a shuttle being launched every week which is what their mission model suggested in the early 1970's. It never really was probably achievable.

But most important, the shuttle was a political compromise. It was intended to be a fully reusable vehicle. It is not. It was intended by NASA to cost initially about 10 billion in early 1970's dollars. The political leadership of the U.S. was unwilling to spend that kind of money and cut the program back to $5.15 billion in early 1970's dollars. That forced NASA to compromise much of the technology.

So in answer to your question, I want the best possible engineers I can find. I also want the best economists I can find. But mostly I want politicians who will say we're either going to do this right and we'll expend the resources necessary to achieve it or we're not going to do it at all.

Max Faget, the legendary designer of the Mercury spacecraft and who had a hand in all of the other vehicles, said it best: "If we are unwilling to make the investment to build a space vehicle that is safe and reliable, we ought to be ashamed of ourselves."

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Columbia, Md.: I have a hard time grasping how foam can damage tiles designed to withstand extreme temperatures and speed in flight. How heavy is this foam, and at what kind of speed is it hitting the shuttle during lift-off?

Roger Launius: The foam in itself is not particularly heavy but the piece that hit Columbia in 2003 and broke a hole in the reinforced-carbon/carbon leading edge did so at more than 500 miles per hour. Even a small piece of debris at that speed will do damage.

The other thing to remember about the shuttle tiles is that they are a form of ceramic. They're quite tough and certainly they're heat resistant but if you struck one with a hammer you could break it.

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Falls Church, Va.: Why is it so important to use the reuseable shuttle. Why doesn't NASA go back to single use rockets? Aren't rockets cheaper and just as effective?

Roger Launius: There's been a huge debate over whether or not you should use reusable launch vehicles (RLV) or expendable launch vehicles (ELV). The shuttle, of course, is the only reusable launcher in the world. When NASA envisioned building the shuttle in the 1060's, it had in mind airline-like operations. And it used the analogy, if an airline flew from New York to Chicago and you threw the airplane away at the end of every flight, you would not be in business very long.

So it made sense from their perspective to build a reusable vehicle. Those who advocate ELV's believe that you can reduce the cost of constructing one of those on an assembly line so that its systems only have to work once and can therefore achieve an economical launch capability using that approach.

There are pluses and minuses on each side of that argument. The next vehicle that NASA has on the drawing board is the crew exploration vehicle (CEV). It could conceivably be reusable but it also may be expendable. And the launcher for it, the rocket, per se, will probably be an expendable rocket.

NASA is still in the definition phase of CEV, so we don't know yet what the system will consist of, so stay tuned.

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Washington, D.C.: Stuff has always fallen off the shuttles during launches, including a very serious foam peel in 1997. Shouldn't NASA scrap the program, which is due for phase-out in 2010 anyway, and build the next generation of space ships that will carry us to Mars and beyond?

Roger Launius: There is a possibility that they will choose to end the shuttle program earlier than 2010 and at this point the principal reason for returning the shuttle to flight is to deliver modules that have already been built and are awaiting launch to the International Space Station (ISS).

Without that requirement it is quite likely that the shuttle would have been retired in 2003. There are plans underway to develop the next generation CEV that will have the capability to go not only into earth orbit but with some modification to the moon.

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Roger Launius: It's possible that there may be some additional modifications to the CEV that would enable it to go on to Mars but it's more likely that there will be a total reengineering of a Mars exploration vehicle sometime in the future.

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Los Angeles, Calif.: Why would NASA make this announcement about grounding future flights while these astronauts are still in space? It seems incredibly insensitive. How frantic does this make the astronauts' families, wondering if something horrific will happen upon re-entry? Couldn't NASA have waited till the astronauts returned to Earth? Or, does NASA think something could go wrong and they are bracing us for the worst?

Roger Launius: I actually think that many people saw with the new cameras debris fly off of the external tank during the launch on Tuesday and that questions began to be asked at that point by media so they didn't have the option of not talking about it. With that as the case, it's best to be very open and upfront about what the situation is. The crew understands that and so do the folks at NASA.

I should add that despite the debris that came off of the external tank, data thus far does not suggest that there was any serious damage to the Orbiter, so there is every reason to believe that they will be able to return safely from space.

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Roger Launius: Thanks very much for joining me on this online chat. These were some terrific questions. I hope I've been able to offer some insight and of course we all look forward to the successful completion of the current shuttle mission.

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