Bill,
The long-term production difference in question, by definition, is a
factor of five times. Not 2:1 either way around a base of 12/year.
SpaceX knew this going in. Being sensible people /not/ locked into the
established way of doing things, they likely would have set up a
production establishment for sixty expended cores a year very
differently than they did the plant for ~12 5X reused cores. Twelve a
year, as you say, is pretty much craft production - modest production
tooling and a lot of very skilled hand labor, low plant investment but
relatively high ongoing personnel cost. 60X a year is still not exactly
Willow Run, but sensible people planning that would very likely invest
considerably more in plant and tooling so as to not require5X the
skilled personnel plus 2nd and 3rd shift differentials, working in
~2X the modest 12/year plant (assuming it was originally run one-shift).
Yes, I oversimplified by saying "1/5th the size of production
establishment". Thought I'd allowed for that sufficiently with "(to a
first approximation)", oh well. And yes, "size" was not quite the mot
juste; "cost" might have been closer to what I was driving at.
My basic point: SpaceX gambled on 5X reusability to greatly reduce their
up-front investment in, and ongoing cost of, F9 booster production. And
they seem to have won. By a quick count, 92 F9 booster core flights so
far, and already over half of those (51) have been used boosters. The
used proportion will only rise from here. And they did this on the
up-front investment for a dozen a year.
In other words, one of the reasons they're so far ahead of the game now
is they gambled and won bigtime on a major-capital saving shortcut at
the start. I hope that's clearer.
Henry
On 3/23/2020 2:00 PM, William Claybaugh wrote:
Henry:
It isn’t clear to me that there is all that much difference between making 12 per year and making 6 or 24.
One saves the material costs and the marginal labor cost but the infrastructure doesn’t (or at least shouldn’t) change much over that range of production.
That said, if you optimize your system for four units per year you will find making 24 more costly than a line optimized for twenty-four.
But rates of a few dozen per year—or a few hundred—all fall into “craft production” and are not going to show economically significant variation on production costs. The benefit of even a few reuses is in the depreciation of the hardware cost over multiple launches.
Bill
On Mon, Mar 23, 2020 at 2:24 PM Henry Vanderbilt <hvanderbilt@xxxxxxxxxxxxxx <mailto:hvanderbilt@xxxxxxxxxxxxxx>> wrote:
Another way of looking at this that I think is relevant: 5-reuse
boosters allows SpaceX to support a given flight rate with (to a
first approximation) 1/5th the size of production establishment
they'd need for fully expendable operations.
Henry
On 3/23/2020 8:12 AM, William Claybaugh wrote:
Robert:
There is too little data to make any assertion about stage
longevity at this point.
However, ignoring propellant and launch operations costs, five
flights per booster would indicate a cost per booster at 20% of
the manufactured cost, not including refurbishment between
flights. The former is around $30-35 million, so $6-7 Million
per flight, again, not including refurbishment. If an overhaul
costs more than about $6 million, it would make more sense to
simply build a new five launch lifetime stage.
We may note that compared to a $50 million price, these
depreciated stage cost estimates suggest either a good deal of
profit or that other costs (launch operations, refurbishment) are
high.
Bill
On Mon, Mar 23, 2020 at 8:51 AM Robert Steinke
<robert.steinke@xxxxxxxxx <mailto:robert.steinke@xxxxxxxxx>> wrote:
From hobbyspace.com <http://hobbyspace.com> about the latest
Falcon 9 launch:
" A first stage engine shut down prematurely (just before
staging) but had no effect on the mission as the other 8
engines made up the difference. The booster also failed to
make a successful landing on a sea platform. This was the
fifth flight of this booster."
That was after a previous launch attempt aborted due to
slightly high power.
Wonderful demonstration of engine-out fault tolerance, but it
does look like the rocket is showing some wear and tear after
5 flights. What does this do to their economics if stages
need an overhaul/have an increased chance of loss of vehicle
after only 5 flights?