I commented on this over at hobbyspace, but felt this deserved its own quick little blog post.
Every now and again, people will trot out a tired argument that HLVs are proven to be much cheaper per pound than smaller vehicles. Or that expendable HLVs are much cheaper than reusable ones like Shuttle. The people then trot out the marginal cost of the Saturn V: ~$431M, and say “look, it only cost about $1700/lb, that’s cheaper than anything we have today”, and usually go on to conclusions about how “if we hadn’t retired the Saturn V, we would have been able to accomplish so much more”.
There’s a couple simple problems with this analysis:
- You can’t compare costs in 1967 dollars to 2006 dollars without factoring in inflation. If you use the inflation calculator, that $431M in 1967 is supposedly equivalent to nearly $2.5B in 2006 dollars. That’s nearly $9k/lb, which is three times worse than existing EELVs. Even if you disagree with the methodology of that inflation calculator, some inflation has occured. Here’s a link to a NASA site with several different inflation calculators. Only the most optimistic two would place the marginal cost of a Saturn V at less than $2B each, and the worst was nearly $3B each.
- You can’t compare just the marginal cost of a government program to a commercial program that also has to cover its fixed costs. A fair “apples-to-apples” comparison involves factoring in both fixed and marginal costs. When you choose to keep a vehicle around or to use a vehicle, you have to pay for those fixed costs. They don’t come for free, so just handwaiving them away doesn’t work. According to the Wikepedia site, about $6.5B was budgetted for Saturn V over the period of 1964-1973, with the peak being $1.2B in 1966. Adjusting for inflation (and assuming naively that you can just divide the total program cost by the number of years to get an average since more detailed info isn’t easily available), you get the equivalence of somewhere between $3B-4.5B per year. The maximum flight rate for Saturn Vs was 4 per year. However, you spend that amount whether you launch one or four missions. Sure, you could probably cut back a bit if you were going into a one-flight per year mode, but the end result is you’re talking at best $3.5B per flight of Saturn V (assuming 4 flights a year), and at worst something in the $4.5B per flight for a one-flight per year tempo (assuming you could halve fixed costs and still keep a flight per year in the system) That comes out to nearly $17k/lb to orbit, which is actually more expensive per pound than Shuttle at 4-5 flights per year!
- Even keeping one-two Saturn V flights per year going would have cost $4.5-7B (in 2006 dollars), which would’ve been something like 50-70% of NASA’s total budget.
Just food for thought next time anyone pines about the loss of the Saturn V. With the amount the NASA budget was slashed by Nixon, had they kept Saturn V, they could’ve afforded almost nothing else. There would’ve been no money for big space stations, there would’ve been no money for a continuing moon program, there would’ve been no money for Voyager and all the rest.
And the sad thing is that we’re making the same mistakes again. We’re tying ourselves down to expensive vehicles that cost billions of dollars not-to-fly, and billions more to fly occasionally. Dumb idea. I wish NASA’s inability to learn from the past wasn’t dooming us to have to repeat it with them. Here’s to hoping that this time around we have a solid alternative. Then NASA may end up facing what we have to out here in the real world. You either learn and adapt, or you die.
Anyhow, that’s enough for now. It’s off to work now.
[Update: I was looking through the numbers I referenced, and some of them may be at least slightly incorrect. Apparently the $431M per launch number actually came by dividing the other number (the $6.5B) by the total number of Saturn V’s flown. So that may have included development costs and fixed costs as well as marginal costs. However, there are a bunch of other funding categories listed that might also be “fixed cost” related that weren’t included in the $6.5B number. If the total cost per flight was really “just” $431M in 1967 dollars, then the numbers aren’t quite so bad. It’s only 70% as expensive as the shuttle…which is to say still more expensive than most other launch vehicles. But it’s hard to tell 100% what the fixed costs were, and therefore how much it would have cost to keep Saturn Vs flying had it not been for Nixon “being so shortsighted”. Does anyone have any better data they can bring to the table? Stuff that more clearly separates out what percentage of the other categories are actually Saturn V operations related?]
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