JF Mezei wrote:

On 2017-10-28 15:38, Jeff Findley wrote:

So what? They're doing better at turning around recovered first stages
to be re-flown faster than any of the competition


The only "re-use" competition is the Shuttle and it wasn't a commercial
endeavour.

Landing a just launched stage doesn't save any money. It costs money.

Launching a payload with a re-used stage 1 is what saves you money.


But SpaceX is going to the trouble to land them, so presumably they
think they're going to save money.



The Block 5 has improvements to the design to help with reuse.


One could infer that those improvements are a sign that the current
Falcon 9 is harder to re-use as the cheer leaders say it is.


One could infer that if one was an idiot. Sane people with actual
working brains would infer that the current Falcon 9 is harder to
re-use than they would like it to be, which is something entirely
different than what you said.



SpaceX
will only get better at this while the competition (aside from Blue
Origin, who's still working on the BE-4 engine for New Glenn) are not
even trying to reuse anything.


The argument isn't whether SpaceX is ahead or other or not. The mere
fact that they have demonstrated they can land a stage, and have re-used
at least 1 stage means they are way ahead of anyone else.


I'm surprised you remember this, Mayfly.


But that doesn't mean that they have proven that they can already
quickly turn around every landed Falcon 9.


But that would certainly be the way to bet. This will never be
'proven' to your satisfaction, because there will always be more
stages to turn around.


They've demonstrated the concept, they've demonstrated they can land
stages, they have demonstrated they can refly at least 1 stage. But
havent yet demonstrated they can have short turn around between landing
pad and launch pad such that it allows high launch rate OF RE-USED STAGES.


Nor do they need to. You seem quite confused about how this 'needs'
to work to be viable. Turn around doesn't need to be particularly
"short term". It just needs to be cheaper than manufacturing a new
one, which is pretty much a given. If my total launch rate is 17
launches per year and I have 34 'used' stages in stock, I can take as
long as a year to 'turn' them and still meet launch schedules. Not
that it will take that long. You could completely disassemble,
inspect, and reassemble the stage in much less time than that.


Just because it is very likely that they will be able to turn these
around quickly doesn't translate to them having demonstrated it.

Just because there are improvements coming that will make future refurb
even easier doesn't mean that they have demonstrated it already.


They will never 'demonstrate' it to your satisfaction, nor do they
need to.



The crush core is more likely to be used up on high energy launches.


On a commecial aircraft, after a hard landing, the aircraft is put "off
line" for inspections. So I would assume that if a crush core gets used
up fully, the stage may require more time to be certified for reflight.


I would certainly expect so, BUT THAT HAS NEVER HAPPENED IN THE ENTIRE
HISTORY OF FALCON 9.


I am not questioning the huge game changing advantage SpaceX has in
having developped re-usable stages. Am not questioning that they have
proven they can land stages and re-use at least 1.

What they haven't proven yet is the ability to ramp up refurbishement to
do quick turn around from landing pad to launch pad. It's too early for
them to have demonstrated it.


They don't need to do it. That's not the point of the exercise.
Nobody is talking about refueling a stage after it lands and reusing
it immediately for any Falcon rocket. Unless you think the cost of
landing, reconditioning, and reusing a stage is more than the cost of
a new stage (and if you do you're a Falcon idiot), SpaceX has proven
everything it needs to prove.


--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn