Monday, June 02, 2008

Fix on Fail?

I have an avid interest in most things having to do with space travel and transportation. This morning I was poking around the "Black Hole of Time" - otherwise known as Wikipedia - and looked up the articles on the three remaining space shuttles, Discovery, Atlantis, and Endeavour. I came across something on the article for Space Shuttle Atlantis that made me go "Wha?".

I'm sure a lot of you have seen the movie Armageddon. The movie is renown for its extremely high level of scientific inaccuracy. Actually, let's just call it what it is: plain unadulterated Hollywood bullshit. However, there is one line that rings very true:

As they're piling into the space shuttles, getting ready for launch, Steve Buscemi says: "You know we're sitting on four million pounds of fuel, one nuclear weapon and a thing that has 270,000 moving parts built by the lowest bidder. Makes you feel good, doesn't it?"

Fast forward 10 years after the movie was made, and I read this on Atlantis' Wikipedia page:
NASA announced that 24 helium and nitrogen gas tanks, named Composite Overwrap Pressure Vessels, in Atlantis are older than their designed lifetime (designed for 10 years, later cleared for another 10 years but in service now for 22 years).

NASA said it cannot guarantee any longer that the vessels on Atlantis will not burst or explode under full pressure. Therefore, the vessels will only be at 80 percent pressure as close to the launch countdown as possible, and the launch pad will be cleared of all but essential personnel when pressure is increased to 100 percent. A launch pad explosion could damage parts of the shuttle and even wound or kill ground personnel. An in-flight failure to the vessels could even result in the loss of the orbiter and its crew.

Because the original vendor is no longer available, the vessels cannot be rebuilt before 2010, when the shuttles are scheduled to be retired. NASA analyses originally assumed that the vessels would leak before they burst, but new tests showed that they would burst before they leak.

The new launch procedure, of clearing the launch pad of all but the essential personnel and pressurizing the tanks to 100 percent as late as possible, will now be conducted during the remaining Atlantis launches if no other resolution is found. Atlantis will have to fly at least one more time in this setting. It is unclear, but possible, that Discovery, which will launch another five or six times, has the same problems and if the same launch procedure needs to be conducted with Discovery. Since Endeavour, which will launch another six or seven times, was built much later, around 1990, it is possible that Endeavour does not have the same problem.

Um, wha?

Space travel is a dangerous operation. When you combine fragile lightweight spacecraft, massive amounts of fuel, millions of different parts built by different companies, and forces of literally astronomical proportions, little problems can become big ones in an instant. Take the Columbia disaster: a foot-wide hole in a wing cost 7 people their lives. Here on Earth, an F-15 can land with its entire wing missing. In Columbia's case, the stresses and temperatures involved with atmospheric reentry turned that small hole into a golden opportunity for superheated material to pass through and melt the spacecraft's innards.

No one knew about the hole in Columbia's wing before they began reentry. But they do know about these tanks on the three remaining space shuttles. Now, they've reviewed them again and say that if they do blow, they probably won't lead to the loss of the orbiter. No guarantees. Instead, they'll take a few "feel good" preventative measures instead of outright replacing the tanks. You can read about specifics of the tanks here.

How would you like to be sitting in one of those seven seats in the orbiter's nose when that countdown timer hits "00:00:01"? Especially since:
  • The entire launch pad area has been cleared because that spacecraft you're sitting in has a reasonable chance of spewing parts on unassuming NASA workers.
  • Scientists have determined that if one of these tanks "goes", you'll get no leak as a warning. You'll just get a nice, reassuring BOOM.
  • If that BOOM happens when you're hurtling through 80,000 feet at high Mach, you better hope what happens next will be painless.
Considering that these tanks were built nearly 25 years ago, it'd be ridiculous to think that no modern vendor could machine new ones. If the Soviets could reverse engineer the state-of-the-art Boeing B-29 bomber down to the rivet in the 1940's, a modern tech company should be able to create a pressure tank. How much time could it take? I'm no engineer, but NASA has shown that where there's a will (and funding) there's a way. That's how we got to the moon using computers no more powerful than a modern calculator, isn't it?

What's also telling is that these were a known issue.... 12 years ago! They've had plenty of time to rectify the problem. Now, of course, it's too late they say. The shuttles are being retired in 2 years. Why spend the money now on a system that's becoming obsolete and when there's no guarantee of failure? "We'll just keep people away from the launch pad, make sure our insurance is paid up, and everything will be fine."

However, if there was an absolute guarantee of failure, you know the money would materialize. Thanks to Challenger, the rocket boosters were redesigned and NASA's culture was revised. Thanks to Columbia, the external tank was redesigned, numerous monitoring cameras added all over the orbiter, and an external arm added that would check the underbelly of the orbiter once it reached space. Were these measures unavailable prior to 1986 or 2003? No, but the outcry from the public community and the resulting funding wasn't.

The difference between Columbia's disaster, Challenger's explosion, and the issue with the remaining shuttles is that Columbia's disintegration was caused by an unforeseen event. Challenger's engineers warned the launch officials that there would be issues with the O-rings and they went ahead anyway. BOOM. And now we have these tanks that have dubious structural integrity, and they're going ahead anyway. BOOM? "Maybe" is the word of the day.

Putting money before safety is a dangerous tactic, which is ironic when you consider the costs involved. Discovery is currently in orbit right now, delivering a $1 billion lab to the space station. The launch itself cost $500 million. To build a new lab would be another $1 billion. A 2nd launch, another $500 million. If Discovery - God forbid - had exploded on its pad or torn itself apart after liftoff, would that have counted as a guarantee of failure?

It's a classic example of a government agency betting on the come with people's lives. While they are taking some minor preventative measures, it seems more like a band-aid instead of a real solution. They just continue pushing until something breaks. After the accident happens and the fires are put out, then they become reactive and take steps to fully correct the problem, spending the money they should have spent in the first place.

Unfortunately, this "fix on fail" attitude does absolutely nothing for those that were killed in the original failure.

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