The Challenger Disaster Page #7

Graham, make sure you have a section model of a SRB joint.

Are we late? We're good for time.

Hey. Morning, General. I guess this is it.

Good luck.

Would the witnesses please rise?

Do you swear that the testimony you will give before this commission

will be the truth, the whole truth

and nothing but the truth, so help you God?

I do. I do.

Mr Mulloy, did you have any apprehension

that a delay in launch would reflect badly on you or NASA Marshall?

No, not at all.

My decision to proceed with the launch as recommended

by the Thiokol official was based solely on the data

presented by Thiokol Engineering. Here comes the smoke.

This is shot right about August 19th,

and the thing of interest here is what we have seen in the O-rings.

See, the fact is, before Challenger, we had seen

no anomalous O-ring erosion for about a year.

Mr McDonald stated that he thought that what had been said was

very important - that the secondary O - ring was in a position to sealed

during the time of blow-by.

So you interpreted Mr McDonald's comment

as a statement in favour of proceeding to launch?

Yes, I certainly did because Mr McDonald was seated close by,

and it was clearly a supportive comment.

I have a question.

Can you remind me what NASA calculates the probability

of shuttle failure to be?

Failure meaning the loss of the vehicle,

and the deaths of the entire crew.

Dr Lovingood.

Certainly. That would be...

...one in ten to the power of five.

Really?

Would you explain that?

Yes, that the probability of mission success is 100%.

Minus Epsilon.

Epsilon. That's a pretty fancy word.

Well, let's put all that you've said there into English.

So that's, that's one failure in every 100,000 flights.

So you claim that the Shuttle would fly every day for 300 years

before there would be a single failure.

That's crazy, I mean, how would you ever even test that?

NASA arrived at that figure because it was a manned flight.

Because there are people on board

but that's not a scientific calculation, that's... that's a wish.

And interesting.

But the figure is very different from that of NASA's own engineers.

Based on their direct experience,

and observation of many known component problems,

some of NASA's engineers calculate the probability of success

as only 99.4%.

In other words, that's roughly one flight in every 200 will fail.

Rogers, time out.

I think this would be an appropriate time to take a break.

One in 200!

Wow. That's not what the astronauts were aware of.

Potential disaster every three and half years.

It won't convince anybody, there's no proof,

people don't get probability, it's math.

But maybe...

The segment joint test we did, the development

and qualification motor test we did, as a basis for understanding

what we could expect to happen on the joints.

Mr Hardy. Certainly.

As we see, the temperature at which the O-rings would lose their integrity

would be in the minus 40 to 50 degree range.

Minus 40 to 50 degrees.

Fahrenheit? Sir.

So they'd maintain their integrity

down to 80 degrees below freezing? That is correct.

Mr Rogers? Oh, yes. Thank you.

These O-rings...

are supposed to expand to make a seal, is that correct? Yes, sir.

So, for the people to understand,

what if we take the O-rings out?

Not have them.

Well, then hot gas would expand through the joint.

For the seal to work correctly, the O-ring has to be made of rubber,

not something like lead, which when you... when you squash it, it stays?

Yes, sir.

Now if the O-ring weren't resilient for a second or two,

that would be enough for a very dangerous situation

and that could likely occur at low temperatures.

No, as Mr Hardy has shown,

they are effective down to minus 40 to 50 degrees.

Well, then I just have one comment for the gentlemen,

that I have always believed that any scientific concept

can be demonstrated to ordinary people,

people with no specialist knowledge or even much scientific education.

Co-pilot to pilot, not yet, just wait. What?

All right. OK, go.

See. I took some of... of this...

stuff from your seal.

And I put it in nothing more than ice water.

And I discover...

...that if you put it under pressure...

...for a while,

and then undo it...

...it doesn't stretch back.

It stops. At the same dimension.

In other words, for a second or two, at least,

and more seconds than that,

there is no resilience in this particular material

at the temperature of 32 degrees Fahrenheit,

the temperature of a cold soda.

I think that has some significance for our problem.

Whatever the eventual Commission Report, I will be writing

up my own independent appendix with all my findings, all the design,

the engineering and the management problems,

which I will be handing to the President myself.

How much did NASA know about the effect of cold, Dr Feynman?

Look. Ask him.

Let us make recommendations

to ensure that NASA officials

deal in a world of reality.

Understanding technological weakness and imperfections

well enough to be actively trying to eliminate them.

NASA owes it to the citizens from whom it asks support

to be frank, honest and informative.

For a successful technology,

reality must take precedence over public relations,

for nature cannot be fooled.

Dr Keel, please.

And Mr President, this appendix has been prepared by Professor Feynman.

And by the way, I think I've figured out who was your source.

You said, "This astronaut, this astronaut. "

If it was a guy, you would have said "he. "

It's OK. I can keep shtoom.

If you ever fancy a ride in that old Buick...

Yeah. If the weather's warm.

It would have to happen pretty soon.

I'm sorry this is taking your time.

I'm not sorry.

I would have been tremendously sorry if we'd lost

but as it is, it was...

Not a good use of science.

It's a good use of science.

I'm OK.

I'm OK with it.

I guess there is a kind of afterlife.

The few bits and pieces that we do might get remembered.

General...

...fix your hair.

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