[AR] Re: Falcon 9 lifetime of 5 flights?
- From: Henry Spencer <hspencer@xxxxxxxxxxxxx>
- To: Arocket List <arocket@xxxxxxxxxxxxx>
- Date: Mon, 23 Mar 2020 15:22:45 -0400 (EDT)
On Mon, 23 Mar 2020, roxanna Mason wrote:
The Shuttle was an abomination any way it's diced and/or sliced. At $1B per
mission, +/- a quarter $B, reuse of any part or component was pretty much
moot. Would be been better to keep flying the Saturn 5 at $1/4B per vehicle.
Careful here -- the *incremental* cost of a Shuttle flight was more like
$100M, much of that being the cost of a new ET. The $1G number comes from
dividing a nearly-fixed annual infrastructure cost by a rather small
number of flights. (Note that the shuttle budget didn't drop during the
years when it was grounded after Challenger and Columbia.) Doubling the
flight rate without any streamlining of operations *would* have needed a
bit more money, but not anywhere near twice as much.
The Saturn V saw some of this too. Comparing costs is very tricky.
Six Saturn Vs a year -- its original launch rate -- would carry payload
roughly equal to 25 Shuttle flights a year (it's an apples-and-oranges
comparison in several ways, but that's in the right ballpark). That sort
of launch volume, handled properly, would have done wonders to reduce
Shuttle per-launch costs too.
Remember that the Saturn V wasn't terminated because somebody decided that
the Shuttle would be better. (NASA wanted to operate *both* -- the
Shuttle was meant to replace the Saturn IB, not the Saturn V.) It was
terminated, *without* replacement, because after the termination of Apollo
and Skylab, there were no (funded) customers for a launcher that big.
There still aren't.
I saw an artist conception of the SIC stage parachuting into the
ocean... Chutes were stowed in the 4 aft fairings where the BSM are
housed. and keep the tanks pressurized for impact resilience...
As Bill has already noted, recovering a high-performance pump-fed stage,
or even useful parts of it, by undecelerated reentry followed by parachute
splashdown turns out to be harder than it looks. In hindsight, there were
omens of this in the history: the S-ICs definitely fragmented during
reentry, *not* on hitting the water. SpaceX never could get its first
stages to survive reentry, and in the end had to switch to Plan B.
Recovering an S-IC intact wasn't a ridiculous idea, done differently.
There was a serious proposal, the "Flyback F-1", to use an S-IC with
wings, jet engines, and pilots as the Shuttle booster system. But its
estimated development costs were slightly too high for OMB's Shuttle cost
cap.
At least get the F-1's back...
Just getting the engines back, after a dunking in salt water, may not be
worth that much. It would be all too easy to end up back in the SRB trap,
where cleanup and refurbishment and retesting costs as much as building a
new one. Some of the folks involved in SpaceX's original concept had real
doubts that even successful splashdown-and-salvage would be worthwhile.
One important side effect of switching to Plan B was that when it works,
you get the whole stage back, intact and dry.
Henry
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