Shuttle disaster: You asked the experts

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Investigators have begun the task of determining what caused the space shuttle Columbia to disintegrate on re-entry to the Earth's atmosphere on Saturday, killing all seven astronauts on board.

US space agency officials have vowed to establish what ended Columbia's 28th flight in such dramatic and tragic circumstances.

But accusations are already being levelled at Nasa chiefs that they ignored a series of safety warnings.

The disaster has also raised questions about the future of the 16-nation International Space Station (ISS).

Tim Boundy from the National Space Centre in Leicester and space expert Heather Couper answered your questions.

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Transcript:

Newshost:
Welcome to this BBC News Online Interactive forum. NASA investigators are getting closer to discovering what caused the space shuttle, Columbia, to disintegrate as it re-entered the Earth's atmosphere, killing all 7 crew members.

They say there was unusual rise in temperature on the left wing, the left-hand side of the aircraft, just before it broke up.

President Bush has now promised an increase in NASA's budget but what will all this mean for the future of America's space programme?

Joining me to answer your many e-mails and questions from the UK and abroad are Tim Boundy, from the National Space Centre here and also Dr Heather Couper, broadcaster and space expert. Welcome to you both.

There is this thing about this damage to the wing - that a bit of foam came off one of tanks. The first question is from John Hughes in Oslo who asks: When NASA were aware of a possible problem during and after launch, was it not possible to inspect the damage, by space walk during the mission, given the dangers of re-entry and the loss of space tiles?

Tim Boundy:
I'm not sure myself - maybe Heather can help me out here - I'm not sure if the astronauts were actually equipped to do a spacewalk on this particular mission.

Heather Couper:
I'll help you Tim. Actually, they weren't - that was the basic thing - they didn't have the suits to do it, they didn't actually have the infrastructure to do it. So it wasn't a spacewalk mission.

This was a purely scientific mission - they had 80 experiments on board. They weren't even going to the international space station. So it was a very focused mission. There was no way of actually checking out if there was any damage.

I gather what happened is that the fragments that hit the space shuttle actually came under the left wing. There were no TV cameras on board there because when you re-enter the atmosphere, you don't want to have extraneous TV cameras sticking out and not helping with the dissent. So there is no way they could have known.

Newshost:
If they had been aware of the severity of the problem, would it have been possible to do something like dock with the space station and organise something for a spacewalk to occur?

Heather Couper:
That's a very interesting point. I was talking my colleague, Francisco Diego yesterday and he was saying that would be an incredibly useful thing to do. That if you think there is going to be a problem, you could dock with a space station and then inspect the damage.

But the irony of the whole situation is that in October - and Tim I was at your fantastic national space centre in Leicester just a couple of weeks ago, talking to the crew who went up to the space station in October on the shuttle, led by our very own astronaut, Piers Sellers - who actually said to me, Heather, you've got to go into space, it's the coolest thing you can ever do. So I'm going to do it, I really am. But they actually had exactly the same problem. They had debris coming off the external fuel tank and that actually impacted onto the solid rocket boosters. But of course those are jettisoned only two minutes into the ascent.

Newshost:
So to be clear Heather, you're saying that this problem of foam coming off has happened before on a previous mission, very recently?

Heather Couper:
Precisely. And again I haven't heard any more up-to-date information that this. But I do remember a very amusing e-mail I got over the summer, saying that the reason why this foam actually goes off the external tank is because it's chipped off by woodpeckers from the local nature reserve.

Tim Boundy:
I've heard that too Heather - I think that's true. They were planning painting the external tank white so that the woodpeckers didn't think it was a large tree anymore.

Newshost:
Tell me a little bit more about that Tim. It should sounds absurd but it could actually be incredibly important as we know.

Tim Boundy:
I'm not sure how important it is. But I've heard stories too that the woodpeckers do actually chip away at the foam. I think they think it's a large tree - obviously they don't find anything interesting underneath it. But I'm sure the external tanks are inspected quite a lot before launch, so if the woodpeckers had done any serious damage, I'm sure they wouldn't have let the shuttle launch.

Newshost:
Heather, we've heard a lot about this issue of burning up the heat. Can you explain to people the physics of re-entry. This is a question from Colin Berry, Antibes, France: Can you please explain the physics of re-entry? Why does it have to be done at such high speeds? Why does it generate so much heat?

Heather Couper:
Basically you have to go in at that sort of angle. You have to go into the atmosphere, just cruising down. This is, if you like, the safest angle to go in. It's not a very, very deep entry - it's not a very acute angle to go in - it's the safest one you could in on.

You've got to remember that what you have to do with the shuttle - let's do in miles per hour to be simple, so that everybody over 50 years old can understand this one. You're travelling at 25,000 miles an hour through space and you have to actually get that speed down to about 200 miles an hour to land and this is the simplest way to do it. There's no way you could actually do multi re-entries and this is the compromise. When the shuttle burnt up it was going at 12,500 miles an hour and believe me there's no slower speed it could go at.

Newshost:
Another e-mail coming in now from Martin Bikiker, which asks: Does the shuttle Columbia have a black box?

Does it have anything on board to record or is it all relayed in real time to land?

Tim Boundy:
I'm afraid our shuttles don't have a black box like you might find on an aeroplane. They don't have some crash-hardened device.

All of the information from the centres is relayed directly to mission control. Mission control don't analyse it all there and then, but it is recorded which is one of the reasons why NASA control shut down directly after the disaster to preserve all the information that they had collected in the computers. But unfortunately shuttles don't have a black box like you might find on an aeroplane.

Newshost:
This brings us onto the question about age and people have mentioned that the shuttle is more than 20 years old. Do you think that age could be related to its weakness on disintegration?

Tim Boundy:
I doubt it. Columbia did have a full refit in 1999. I'm sure they looked at every part of the shuttle and made sure it was easily worthy for space flight.

I know that after every mission, they scrutinise every part of the shuttle and make sure it's ready for the next mission. I doubt age was a factor in it.

Newshost:
Heather, there's been a lot of discussion about how this is 1980s or 1970s technology on board the shuttle. Is that actually true? Or have they pretty much been gutted and had their brains and everything replaced?

Heather Couper:
I've been on board a shuttle - not on board to fly - but I actually made a TV programme about them - and it really is very, very ancient technology. It has been to some extent upgraded. But they have had brain transplants and things like that. But I have to say that it's a slightly unholy compromise between having really up-to-date digital technology with the analogue technology of the 1970s.

What I do feel strongly about - and how many interviews have I done in the last 36 hours, it must be up to about 100. The thing that has been occurring throughout all this is, I think the American Government and the Americans in general have not actually given their heroic astronauts the kind of transport that they need for the future. They should have had a backup, there should have been a space plane - there should have been something that they were planning for the future - and there's nothing, there is just the boring old shuttle.

Newshost:
That brings us on to the second part of the question from Martin Bikiker, London: What are the follow-ups? There's talk about something called the X33, which is some sort of vehicle that might replace the shuttle. What are they and do you think they're now likely to happen or has it undermined these things?

Tim Boundy:
I'm not sure of the progress of the X33 development so far. As far as I know, they were only at test stages - early development stages. I think that was actually designed as more or less a shuttle to go and from the space station.

Newshost:
So there's not much on the drawing board at the moment? So it's shuttle or nothing?

Tim Boundy:
I'm afraid right now, all NASA have is the shuttle or nothing. Of course the Russians have got the Soyez, which has proven a very worthy space vehicle for up to more than 30 years now.

Yes, Heather, I appreciate your point. The astronauts could do with some very nice up-to-date, brand new space craft. But up until now, that would cost a lot of money to develop obviously and I don't know if really need it. They were doing fine with the shuttle so far.

Newshost:
Sarah Smith, Rotherham asks: Are NASA likely to invest in a new shuttle, seeing as only three out of five now exist? And also we've got the space station up there which needs its transport capability.

Heather Couper:
She's absolutely right. No, I don't think we're going to invest in a new shuttle. But on the other hand, the shuttle is the only vehicle that can deliver the hardware that builds a space station. Bear in mind, it's the only vehicle that could actually bring up things like solar panels etc.

But Sean O'Keefe, who's the new administrator, i.e. the big boss at NASA, is saying that in 2010, there's going to be a space plane. But that's far too far off and this space plane is going to be launched by expendable rockets - delta rockets and thinks like that.

I think NASA is being absolutely dreadful in its record. They should be actually planning a new reusable space system. Frankly, I hope they're overtaken by other nations like the Chinese or the Indonesians or the Indians, who are actually planning their own space transportation systems. I think they've been found woefully lacking.

Newshost:
This is an e-mail that's come in live on the subject of the space station. Kevin Simpson, Bracknell, UK asks: How long will the International Space Station have before it needs to be pushed into a higher orbit from one of the USA's shuttles? If not an American shuttle, can something else do the job?

Tim can you answer this one. Does the space station need every now and then to be, in effect, pushed into a better orbit in order to not come back to Earth?

Tim Boundy:
Yes, that is one of the uses of the shuttle. When the shuttle is docked - whether they're doing a crew change, or it's delivering supplies or another part to build that space station - they also boost the space station into a slightly higher orbit because over time the space station degrades its orbit - it drops slightly further down towards the Earth, just quite naturally.

I'm not sure when it will need to happen again. The next mission was due to be on March 1st - that was shuttle Atlantis was meant to go up. I'm pretty sure that that mission won't be going ahead in March. But there are the Russian progress vehicles - they are visiting. In fact one is due to arrive tomorrow. I do know that they have some boosting capabilitie4s but I'm pretty sure they're not quite as powerful as the space shuttle.

I don't know - maybe Heather, do you know when the station will need to be boosted up again?

Newshost:
And also Heather, what are the immediate requirements as regards to crew change? What are the immediate threats for the space station?

Heather Couper:
No immediate threats at the moment. And to answer Tim's question, I think they are ok - certainly in terms of the crew on board - there are two astronauts and one cosmonaut - and they're ok until the end of June. So we're ok there.

But we will need to re-boost the space station - you're absolutely right because otherwise it does decay in orbit slightly.

Newshost:
Another live e-mail is coming in. Rich from Lancaster, UK asks: How much has been discovered about space in the last 16 years in effect by the shuttle missions and was it worth the lives of the crews of the Columbia and Challenger?

Tim Boundy:
As to the question, how much has been discovered - I wouldn't like to start answering that one - just leave it at a lot.

But is it worth the lives? Maybe you should the astronauts - I'm sure they would say yes - they know the risks when they go off into space. And if we didn't send brave, heroic astronauts up into space to do these kinds of things, where would we be going? We also the need the heroes - we need the inspiration really. I use the inspiration and excitement of space flight to educate kids - to educate people - about space. It helps them to learn about science in general.

But I think the astronauts would always say it was worth it. And I know that the astronauts who tragically died would want the manned space flight programme to continue.

Newshost:
Heather, is the manned space programme mainly about heroics and excitement rather than science that's useful on Earth?

Heather Couper:
It's both - absolutely both. I applied to be an astronaut - I got turned down, as did Piers Sellers by the way - our third British astronaut. He applied for the same programme that I applied to and we both got rejected and he actually changed his nationality to be an American in order to become an astronaut. So there's both the vision of flying in space - the inspiration that Tim was talking about - but there's also a great deal of science to come out of it as well.

One of the saddest things about this particular mission - it wasn't a mission to dock with the International Space Station, it was actually a purely scientific mission. They had over 80 experiments on board the shuttle. Things to look for using the unique environment of space where there's zero gravity - though strictly speaking it's not, it's free fall where you've got no forces. You can actually do things like looking at drugs to help diabetes. You can do things with electronics which you can't do on Earth.

So they had all these scientific experiments - they were playing with ball lightening. When you look at those guys on board, there's such enthusiasm. What actually emerged in me this weekend is I've met many astronauts and I like them a lot - they're great people - but they are both visionaries but at the same time they're practically very competent. I can hardly wire a fuse and these guys can actually spout vision and then spout practicality and I think they're unique and ought to be cherished.

Newshost:
Coming back to what NASA are going to do now to the space programme and to other space hardware. Simon from the UK, says that NASA needs to devise a non-destructive way of inspecting the entire shuttle, after lift-off or in orbit, and a repair facility for the damaged ISS. Do you think we are going to see a lot more hardware built into the possibilities of repair?

Heather Couper:
I really don't know. I think NASA is going to have to wait. It was two-and-a-half years after the Challenger disaster that we actually got shuttles back in the mainstream again. I think it's going to be 18 months before we see any shuttles flying again.

I frankly would like to see the whole shuttle programme fazed out all together. Going back to what I said earlier on - our astronauts are heroes and deserve the best from our hardware. In this case the shuttle itself was designed by a committee. It was an unholy compromise between the military and the civilian. The military wanted to have this big bay with a huge a huge amount of space to actually launch their huge spy satellites and the civilian side wanted to have people getting up into space very, very quickly and simply and safely and clearly those objectives have not been met on either side. I think they have to look at the whole thing again.

Newshost:
Mukesh, Singapore: Are there alternative technologies? We know there's not a lot of hardware being built. Are there some really radical technologies of ways of getting out of our atmosphere?

Tim Boundy:
There are a lot of ideas about how we get into space. I think the most radical one I can think of is a huge tower that you build on the Earth and is anchored at geo-stationary orbit and then you winch yourself up a cable - I'm not sure if this is possible or not, but I saw a picture of it the other day.

There are various ideas about flying up into quite high altitudes with normal planes and then actually turning on rocket boosters and jetting off into that direction. Heather do you know any other fantastic technologies.

Heather Couper:
I was thinking about that - it's Arthur C. Clarke's idea isn't it - the space elevator?

Tim Boundy:
He started it yes.

Heather Couper:
But they tried to do something very similar with an Italian experiment on the space shuttle and that failed miserably. I just think we've got to keep going at it.

Isn't it ironic, it's a hundred years since the Wright Brothers blasted off in their first plane and here we are a hundred years on and we have to actually now really go hard at space technology. If we're committed into going into space - and I think we are - the kind of feedback I've been getting over the last three days is that everybody is committed to going into space. So we have to actually find new and innovative ways of doing it.

Tim Boundy:
I agree. We haven't had any sentiment at the space centre that we should stop trying.

Newshost:
A more specific technological question comes from Simon in Manchester who asks in relation to the heat tiles: Have there been advances in materials technology in the last 25 years since this was designed and could that be made more useful to protect future space shuttles?

Heather Couper:
That's a very interesting question because I did a programme called Space Shuttle Discovery where we actually got the astronauts on board to film for us. We took one of the tiles and we put a heat source - a Bunsen burner - on one side and actually you touch the back of the tile. They range between six inches and eight inches across and they're all custom-made for the curves of the shuttle. It was amazing, you could actually touch the back of the tile where you had 2,000 degrees on one side and zero on the back - you could feel that there was no heat getting through.

So I think as to the technology of the tiles - even though they were made 20 - 30 years ago - they're still as good as they were. But I think in this particular case, what happened is some of the tiles must have fallen off.

Newshost:
Just a final thought from Richard in Cambridge: Whilst this is a tragedy, we mustn't forget this is only the second time in 113 missions that the space shuttle has failed so disastrously?

Do you think that the right way to look at it?

Tim Boundy:
It's certainly an optimistic way to look at it. It doesn't lessen the tragedy of course. But I remember when NASA first initiated the space shuttle programme, they had an expectation of 1 in every 100 missions going awry somehow. So now we've had 2 in 113, which doesn't look good. But if you accept that space flight is a very dangerous thing to attempt, then really you've got to accept some things like this going wrong.

Newshost:
Acceptable losses, Heather?

Heather Couper:
Absolutely - I think so. These are brave people. This is a new frontier. At a heartbeat, I'd be up in space myself.

Tim Boundy:
Me too.

Newshost:
That's all we've got time for. So thanks very much to my guests, Tim Boundy and Dr Heather Couper. Thank you very much for your questions. From me in London, goodbye.