A commenter at this post writes:

When it costs hundreds of millions of dollars to fly a single Shuttle mission, I fail to see the problem with spending another 10 to fix the wiring.

The first problem is a misunderstanding of Shuttle costs. The marginal cost of a flight is not “hundreds of millions of dollars.” It’s probably somewhere between a hundred and a hundred and fifty million. The average cost is much more, but that’s not a useful number, because it can vary so much with flight rate (for example, when the flight rate is zero, as it has been since February, 2003, the average cost per flight is infinite, regardless of how much we spend on the Shuttle program).

The second problem is that, while ten million dollars may not seem like much in the context of a program that costs billions annually, the fact remains that NASA has a finite budget, and ten million spent on one item is ten million less available to be spent on something else, that might be more important. According to the article that the original post linked to, the odds of an uncommanded thruster firing resulting in a catastrophe are somewhere between one in ten thousand and one in a million (it doesn’t say if that’s on a per-mission basis, or totaled over the next twenty-odd flights). Assuming that those are valid numbers, with any degree of confidence, then the standard way to determine how much we should spend to prevent that event from happening would be to use the expected value of that event (probability times cost). The problem with that, of course, is assessing the value of either the Shuttle fleet, or the ISS, given that current policy recognizes them both as dead ends, in terms of future space policy.

That, in fact, is why I think that the CAIB recommendations should have been revisited after the new policy was announced. If the CAIB had known that the Shuttle was going to be retired at the end of the decade, they may not have recommended some of the more costly (and impractical) fixes for what would then have been recognized as a rapidly depreciating asset.

This article, describing the potential danger of an uncommanded thruster firing, is just one more illustration of why the Shuttle has to be retired, and the sooner the better.

Back in the olden days, when I worked at Rockwell in the eighties and early nineties, some of my colleagues would write technical papers, in all seriousness, that we would likely be flying the Shuttle well into the 2020s or 2030s. Ignoring the fact that this was a self-serving delusion (we were, after all, in the business of building and flying the things), their logic was that it was designed for a hundred flights, and at the low flight rate we were getting out of it, it would easily last well into those decades. I didn’t make myself very popular when I laughed at this logic, but I did nonetheless.

Setting aside the issue of what a disaster it would be for space policy if we were still flying such an economically absurd system five decades after it had been designed, they didn’t seem to understand that, like the old oil commercial, “think months, not miles.” The fleet is aging, as we saw a couple years ago with the cracks in the fuel-cell liners. The standard rejoinder to this argument is that we are still flying B-52s that were originally built in the 1950s, and in some cases we have grandsons of some of the original flight crews flying them today.

That ignores the economics, of course. B-52s are heavily used, still flying sorties every day, and it makes sense to continue to maintain and inspect them, because the cost of doing so is amortized over a large number of flights. But it’s hard to justify the expenditure of many millions of dollars to replace wiring in the RCS, when the fleet is going to be retired soon anyway, and only flies a few times a year. This logic applies to almost any maintenance/replacement issue with the vehicles, all of which are uniformly hyperexpensive to implement. Unless it’s a clear and obvious safety issue in the context of the next couple dozen flights, it’s very hard to justify the expense at this point.

You know that space tourism is being taken seriously when you can read about it in Travel and Leisure magazine. This piece by Los Angeles writer M. G. Lord was in the January issue, which Patricia just pointed out to me.

I last saw M. G. last June in Mojave for the first SpaceShipOne flight into space. I hadn’t realized that she has a new book out. It looks quite interesting. Check out the review by NASA historian Roger Launius.