![](http://web.archive.org./web/20161111142001im_/https://www.newscientist.com/blog/space/uploaded_images/shuttle-for-ext-blog-755291.jpg)
The internet is abuzz over a
leaked email from NASA chief Mike Griffin that outlines the predicament the agency is in: how to get to space after the shuttles are set to retire in 2010 and before their Ares/Orion replacements are scheduled to start flying in 2015.
Because of
mounting tensions with Russia over the conflict in Georgia, Griffin wrote in the 18 August email that the prospect of getting Congress to agree to buy seats on Russia's Soyuz spacecraft past 2011 is "DoA" [dead on arrival]. (In a public statement released on Sunday, however, Griffin said White House policy "is to retire the shuttle in 2010 and purchase crew transport from Russia until Ares and Orion are available".)
"The alternatives are to continue flying Shuttle, or abandon U.S. presence on ISS [International Space Station]," the leaked email reads. "[The next administration] will tell us to extend Shuttle. There is no other politically tenable course."
Delaying the retirement of the shuttle does seem like an obvious fix, but it poses some problems.
Officially, the biggest stumbling block is the Columbia Accident Investigation Board's recommendation (accepted by NASA) that the shuttle should not fly beyond 2010 without "recertification".
Nobody's quite sure what recertification would consist of, but it's clearly meant to imply major overhauls of the orbiters, checking them over carefully for signs of any problem that would limit their working lives.
The obvious snag is that such overhauls would be big, expensive, time-consuming projects. A more subtle difficulty is that such a search for problems would undoubtedly find some! The youngest of the orbiters, Endeavour, has been in operational service for 16 years; the others are a few years older. If NASA looks hard at these old vehicles, it almost certainly
will find a few things that don't look quite right and ought to be fixed on general principles. There might even be some genuinely serious problems. This will run up the cost still further.
However, NASA can probably avoid opening that can of worms. The CAIB recommendation wasn't intended to say that the shuttle would be unsafe to fly after midnight 31 Dec 2010 exactly. The date was meant as a general guideline, at a time when NASA was talking seriously about flying the shuttle several times a year until 2020 or later.
The simplest way to fly the shuttle for a few more years would be to "stretch" the deadline a little instead, avoiding the recertification issue by being very conservative. Limit shuttle flights strictly to station crew exchanges (plus some associated cargo, as a bonus); that would mean flying it only about twice a year. Rigorously standardise the cargo configuration and mission plan, rather than custom-planning each flight. Set a payload limit well under the maximum, to give wide safety margins and minimise stress on the orbiters. And do at least a minor overhaul on the orbiters, as time permits - the vehicles won't be terribly busy on this schedule - partly to look for problems and partly to appease critics.
Another problem of keeping the shuttle flying longer would be spare parts: not just paying for them, but whether NASA can
buy them at all. Almost all the hardware in the orbiters and their ground support systems is grossly obsolete, since it was mostly designed 30+ years ago.
NASA has already been forced to do some costly upgrades, e.g. the new cockpit displays that the orbiters got in the late 1990s, simply because it had become impossible to get parts for the original equipment. (If the production line has only recently closed, usually you can get some more parts made just by offering the supplier enough money. If it's been a while since the shutdown, though, then the specialised knowledge and facilities may be gone, so the supplier literally
can't make parts that are guaranteed identical to the originals.)
How bad would this problem be for extended shuttle operations? It's hard to say from outside, but the news probably isn't good. In particular, I wouldn't be at all surprised if some problems getting spares got set aside because the shuttle was about to retire. Those will have to be dealt with if the shuttle is going to keep flying for a while. However, for the sort of minimum-stress plan I suggest above, I suspect this can be handled. Perhaps not easily, and it'll take extra money, but I think it could be done.
Mind you, I do think it would be important not to fixate on 2015 as the real, final shutdown date. As I've said earlier,
Ares/Orion is already a troubled programme, and I expect it to run late. A safer bet would be that the last shuttle flight would be sometime between 2015 and 2020. (Personally, I expect it will be sooner, because there will be
commercial flights to orbit before then...but the whole point of this exercise is that NASA doesn't think it can safely count on that.)
In short, I think the technical issues of flying the shuttle a few years longer are probably manageable - given a good supply of money and some cautious planning. However, there are some non-technical (and non-financial) problems which may be harder to solve; I'll talk about them in the third (and last) part of this article.
Henry Spencer, computer programmer, spacecraft engineer and amateur space historian (Image: NASA)