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How many years can a liquid fuel rocket be safely stored (unfueled) between manufacturing and launch? Are they sensitive to slow processes like corrosion, material degradation from dehydration, other chemical processes, seasonal temperature variation, fatigue of load carrying structures, gathering of dust that can clog or cause a fire, or biological activity by microbes, insects, rodents, or a combination of all above? Would it take much to store a launcher safely? On the other hand, they are robust machines built with high quality materials.

For example, an ambitious human mission to Mars would require several launches, preferably within a brief period. Some expect, maybe pessimistically, that only one SLS will be manufactured per year. Could they be saved up for a decade to then be launched as frequently as the space port capacity allows?

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  • $\begingroup$ While not exactly what you are looking for, it seems that they keep fairly well when taken good care of. $\endgroup$ – user Oct 6 '15 at 12:49
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    $\begingroup$ Seal degradation is an issue. Rust can be prevented by storing in helium or nitrogen atmosphere. $\endgroup$ – Deer Hunter Oct 6 '15 at 12:50
  • $\begingroup$ In fact, fuelled hypergolic ICBMs are kept ready for a looong time. $\endgroup$ – Deer Hunter Oct 6 '15 at 12:54
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    $\begingroup$ @DeerHunter Maybe, but those are designed for storage. The SSME is not. $\endgroup$ – Rikki-Tikki-Tavi Oct 6 '15 at 14:08
  • $\begingroup$ Solid or liquid fuel? $\endgroup$ – Jon Story Oct 6 '15 at 14:45
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First of all, I believe the limiting factor on SLS isn't so much the time it takes to build a rocket, but the cost per rocket. As more rockets get launched, the cost will go down per launch.

As for the shelf life of a rocket, there are a couple of key things. The main cost is storage, in that the rocket has to be placed in a controlled environment to protect it for the duration. As time passes, the batteries might need to be changed, some basic maintenance is required, etc. But they can store for some time. I don't think you'd have the decade long storage process, but up to months is done frequently.

One of the most complex parts of a rocket, the engine, has shown to some degree a long lifetime, although it also shows the perils of using such an engine. Antares used the NK-33 engine produced by Russia, which were manufactured at latest the 1990's. They were used 20 years after manufactured. Of course, there were failures, which resulted in them no longer being used.

Bottom line, if you are willing to store them carefully, and check certain key components before launch, you can probably get away with simply stockpiling rockets. But I wouldn't want to store them for 10 years for a human rated mission!

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    $\begingroup$ Actually, storage is a major concern. There are lots of materials in a rocket that can potentially degrade, and the people at Rocketdyne are worried about this. $\endgroup$ – Rikki-Tikki-Tavi Oct 6 '15 at 12:51
  • $\begingroup$ @Rikki-Tikki-Tavi: could you expand on that a bit? Specific components that Rocketdyne are worried about? $\endgroup$ – Hobbes Oct 6 '15 at 21:02
  • $\begingroup$ Gaskets mostly, I think. There was a panel about this and other stuff at the Joint Propulsion Conference some years ago, I don't remember every word that was said. $\endgroup$ – Rikki-Tikki-Tavi Oct 6 '15 at 21:22

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