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.