Government Spaceflight--why is it taking so long?

Tuesday, I talked a little about the Saturn V and touched briefly on the latest replacement, the imaginatively named SLS (Space Launch System).

One of the things I wondered about was why, if we've already built something nearly as powerful, can't we do it again quickly?  I came up with a few reasons:  technology has advanced; safety standards have increased; and politics/government.  The Oct 22 Space News offered up another point:  budgets.

Okay, budgets are part of politics, but what I found interesting is that it's not just budget cuts that are affecting the SLS program, but the fact that the budget does not have room to increase when they need more. 

"If you are a project manager, you know that the development curve wants to be a curve...So if you stack a development curve on top of a developement curve, you get a very acute rise in cost.  One of the things (the SLS program managers) came to very quickly is we could probably afford one development at a time."  --Todd May, manager of the SLS program office at NASA's Marshall Space Flight Center, quoted in Space News

Because of this, they have to move more slowly, going a piece at a time.  That's one reason why they won't make their first flight until 2017 and the first crewed flight until 2021--and they will be using a different booster by that time, too.

On the bright side, budget cuts are resulting in NASA cutting down on contractor oversight, which, according to Space News, means they'll lean more on industry standards as opposed to NASA tradition.  That could be a good thing, and in fact, some companies (like ATK) say that will let them speed up production in some areas (reducing cost in the process.)