Discovery's flight was the first shuttle mission for NASA since the February 2003 Columbia disaster. This mission had its own challenges — foam insulation loss at launch, a torn thermal blanket underneath one of the cockpit windows. Discovery's safe return to Earth Tuesday was a boon for NASA, but it also raises questions about the future of the shuttle program and the challenges it still faces. Space historian and Morning Edition commentator Andrew Chaikin addresses some of those issues:
After Columbia, much was made of the need for changes in NASA's culture. Has any evidence of that kind of change become apparent during the Discovery mission?
I think so. The most important change that had to be made was to correct the mindset NASA had fallen into about safety, before the Columbia shuttle accident. Simply stated, that mindset was "You have to prove something is unsafe; otherwise, we'll conclude that it's OK to fly" — instead of "Prove to me that everything really is safe. Otherwise, we won't go ahead." That's the fundamental thing that had to change, and from what we've seen during this flight, it does appear to be changing.
Pre-launch problems with a fuel valve; foam losses during launch; protruding gap fillers in the shuttles underbelly — NASA has taken every safety issue as it's come up and made very, very careful decisions about what to do.
Now, as to what is going on at all levels of NASA — whether people are communicating openly about problems and whether they are really listening to one another — that's difficult for us to know from the outside. But we'll have to see how things go from here on.
Why, after two-and-a-half years and vast resources spent on fixing the shuttle, did NASA still experience problems with the fuel tank?
There are two reasons, I think. One is that the problem of keeping foam from falling off the external tank during launch is apparently a very difficult technical problem. The foam must adhere well enough to the metal skin of the fuel tank, which is very cold because of the propellants inside it. And it has to withstand all the vibration and aerodynamic forces it experiences during launch.
Second, even with all the testing NASA did before flight, there was still no way to fully predict how well the foam would hold up without actually going ahead and doing a launch. One of the purposes of this flight — which NASA officials have said all along was a test flight — was to show whether they really had solved the problem. And it turned out they hadn't; there's more work to do. Having said that, we really need to acknowledge that Discovery had much less damage than most shuttle flights in the past, and all that preflight effort did result in a tremendous improvement.
Is NASA likely to adopt spacewalks as a standard repair procedure?
I would think so. Keep in mind, though, that the "repair" that was done on this flight was pretty minor, compared to what might have to be done in the future. Steve Robinson had to be extremely careful when he pulled out the two gap fillers, to avoid causing damage to the bottom of the orbiter.
But when you talk about actually repairing tiles in space, that's getting pretty "sporty," as one of the Apollo astronauts used to say. Shuttle managers are still trying to work out the techniques for doing that — in fact, they tested those methods during Discovery's flight. It's unclear whether those techniques would actually work well enough to protect the orbiter during re-entry. But spacewalks are part of the arsenal, so to speak, that is available to solve problems on shuttle flights. And if that were the only way to handle a problem, I'm sure NASA would try to use it.
What does this mission suggest about the challenges still facing the shuttle program?
Mostly, it confirms the fact that, at some level, every shuttle flight is going to be a test flight. That's why you saw NASA managers resisting the media's use of the word "grounded," as if the decision to postpone future flights until they fix the foam problem is some kind of catastrophe. The way to look at this is that every mission is potentially going to turn up problems that must be solved before the next mission can fly. And that attitude on NASA's part is another sign that its safety culture has changed for the better.
What does NASA have planned for the next generation of space vehicles?
NASA is considering creating one vehicle to carry people to and from Earth orbit, and a different vehicle, more powerful but unmanned, to carry cargo. I think that's definitely the right way to go. Make the manned vehicle as safe and uncomplicated as humanly possible. Give the astronauts a means of escape during launch if there's a problem with the rocket. Protect the heat shield so nothing can damage it during launch. NASA is considering concepts that address all those issues.
However, it's going to take time, money and expertise to create those new vehicles. That's going to be even tougher to do while NASA is still spending money and resources to keep the shuttle flying. With the White House mandate to stop flying the shuttle in 2010, NASA can't take an indefinite amount of time.
What happens with the international space station in the near term?
In the near term, the goal is just to get as much of the station assembled as possible. That, of course, will depend on how many shuttle flights can take place. Mike Griffin, the NASA administrator, has already said that the number of flights left — I believe it's no more than 15 — might not be enough to completely finish the station. That's the reality everyone is going to have to live with. What's most important is to get the station to the point where it can support more than two or three astronauts, so you have enough people up there to do some significant research, as well as just keeping the station operating.
But there are still questions about how NASA is going to use the station, and how it should use it. Up to now, many people have been pushing to use the station to solve the medical problems of a Mars voyage — how to protect people from the effects of weightlessness, space radiation and so on.
But it may be that some of those medical problems aren't as bad as people have thought, and others could be solved with research on Earth. For example, loss of bone minerals in zero gravity has been a big worry in the past, but some of the astronauts who've spent six months on the station have come home without any real bone loss because of new exercise routines.
And the best approach to space radiation might come from experiments being done on Earth, in places like Brookhaven National Laboratory. I agree with the people who say that the station would be an ideal place to test new technologies for manned space exploration, things like closed-loop life support systems that would be essential on a voyage to Mars. I'm not sure NASA has figured out what it is going to do in that regard.
If shuttles don't fly for an extended period of time, how will the space station get supplies? Russia is the only partner with a spacecraft that can go up there. (And the U.S. can't actually pay the Russians to do the job for them, right?)
That's right; the Russian Soyuz is currently the only means of getting to and from the station as long as the shuttle is grounded. The Russians have done a super job of handling that need. But U.S. law currently bans NASA from paying for that service. [A provision of the Iran Nonproliferation Act of 2000 bans U.S. payments to Russia in connection with the space station, unless the president determines Russia is taking steps to prevent nuclear proliferation. The measure was designed to try to get Russia to cooperate in efforts to stop the transfer of nuclear weapons technology to Iran.]
Moreover, many people are uncomfortable, understandably so, with the idea of a foreign country providing the only access to space for our astronauts. So that's another reason to push ahead with the development of new vehicles.
How does the suspension of shuttle flights affect plans for the manned mission to the moon and then to Mars that President Bush has called for?
If it turns out that the shuttle must be grounded for a long period of time — either now or in the next few years — I think the biggest problem is going to be maintaining a workforce that knows how to tackle the difficulties of human spaceflight. You have an incredibly talented, dedicated cadre of people who have been seasoned and honed by the shuttle flights, and it would be very, very bad to lose that expertise because of an extended hiatus.
Where do plans for that mission stand?
Plans seem to be moving ahead, although NASA has had its hands full with getting the shuttle flying again. People are certainly working on designs for the new space vehicle and on plans for these missions, which are going to be very demanding, very challenging.
The real challenge right now is developing an infrastructure in space. We need flexibility and reliability and safety, all at the same time — and we need to achieve those things without breaking the bank. It almost sounds like an impossible goal. But it's important, and not only because we want to get back in the business of exploration with both astronauts and robots. We really need to overcome the basic hurdles of access to space, which the shuttle didn't solve. I can't think of a more important task for all that talent and brain power at NASA.
Andrew Chaikin is the author of A Man on the Moon: The Triumphant Story of the Apollo Space Program.