Henry:
Terms matter: what you are talking about is depreciation, not production
savings.
I’m will to be educated but I would be shocked if making 1/5 as many
vehicles resulted in a production system 1/5 the previous size: that is
simply not how production works.
There are high fixed costs in any production line as well as minimum costs.
Bill
On Tue, Mar 24, 2020 at 8:49 AM Henry Vanderbilt <hvanderbilt@xxxxxxxxxxxxxx>
wrote:
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 require 5X 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> 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>
wrote:
From 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?