JF Mezei wrote on Wed, 2 Jan 2019
20:16:34 -0500:

On 2019-01-02 07:05, Jeff Findley wrote:

They do? What the maximum number of times a bloc, 5 has been re-used so
far ?

Yes, they do. Three. Note that they're still doing inspections and
some parts replacement between flights.

So they have now officially downgraded their original plans of between
10 and 100 launches down to 3?


You asked the maximum number of times a Block 5 has been reused. That
answer is three. You asked one question and have now taken the answer
as the answer to a totally different question. This is intellectually
dishonest at best and unable to read English at worst.


If they have only 3 in their experience so far, but still plan for much
higher number, my statement still standsL they doN,t yet have the
enxperience to know how many launches a stage can really do.


Bull****. As I pointed out, you don't have to 'test to destruction'
to have a pretty good idea of where 'destruction' will (or won't)
occur. You don't know **** about engineering, do you?

snip misunderstood info


I seriously doubt that the launch contracts are worded that way.
Customers want the earliest launch possible, so why would anyone specify
that they want to wait until the 9th launch of a first stage?

There was a big discount for the first commercial reflight, and that
customer was willing to wait for it to save money.


Cite? I thought not.


And I assume that
until SpaceX has solid experience in reflights, those that push the
current limits of its experiece (now at 3) will come at a discount (and
insurance more expensive).


You 'assume' many stupidly counterfactual things while disregarding
actual statements from people who know, from Elon Musk on down.


You do know that after 10 flights they plan on refurbishing the booster
for even more flights, right?

I was using 10 as a total launch limit to show that you'd want DoD who
want a "no landing" launch to be given stages that are near end of life
instead of brand spanking new ones.


I doubt DoD (or other expendable customers) are willing to wait the
number of years they would have to wait to get something "near end of
life".


And since they have only reflown 3 times, I am not sure the number 10
for the major refurb has been decided.


It may be more than 10. I doubt it will be less. Of course, they may
get a big enough pool of Block 5 boosters built that none of them will
even come close to that.


Block 5 first stages are designed to fly up to ten times with
little to no refurbishment. In fact, with a scheduled maintenance
every ten flights, it will be possible to launch a Block 5 first
stage up to 100 times.

Musk aspirational goals.


Bull****. Musk goal as Chief Designer. Engineering takes direction
from him.


Not standards based on empirical evidence since
they haven't even reached 1 stage with 10 re-uses yet let alone 100.


We don't do 'empirical engineering'.


Not saying they won't achieve this, just saying there is no assurance
they will at this point.


You really don't know **** about how engineering works, do you?

I'd expect SpaceX to want to expend the booster with the most flights,
not one with 9. But the customer might still want a "new" booster on an
expendable launch, so you charge the customer more money (so you can
manufacture a replacement booster) and carry on.

A one off isn't a big deal. But if DoD becomes a major customer and
wants all its launches on brand new stages without landing capability,
then this changes plans, especially when they try to transition frm
Falcon9 to BFR and try to shift resources to producing BFR.


Preposterous opinion based on NOTHING.

customer as well. Currently Falcon Heavy has only flown once. So a
customer like DOD might prefer a "single stick" Falcon 9 since it has a
far longer track record.

Shotwell said the main reason Falcon Heavy wasn't cancelled was that she
had already lined up DoD as customer for it.


Yep. That want a 'second source' for the Delta IV Heavy mission
space. But then, other people want Falcon Heavy, too, so Shotwell is
exaggerating or you misunderstood what was said. See, for example,
the ArabSat launch scheduled for next year.

I really don't understand all of your hand-wringing here. It makes no
sense.

The argumenmt I am trying to make is the business model of falcon9 is
re-usability. If one customer pops up and requires non-re-usable
Falcon9s and becomes a major customer, then this changes the business
model because SpaceX is now needing to produce disposable Falcon9s are a
much higher ration than the original business model had antitcipated.


The point you're trying to make is poppycock. You need to go look up
the grand total of Delta IV launches by year. It's not very many in
the grand scheme of things and certainly not very many when compared
to the couple dozen commercial launches that Falcon 9 makes each year.


So this also changes any plans they had to reduce production so
resources can be assigned to ramping up production of BFR/BFS.


Not by much, if at all.


Remember that BFR/NFS will be a HUGE drain on cash, and if it was to
have been funded by re-using Falcon9s a lot instead of building new ones
all the time, and now, they have to keep on building them, this changes
things.


They wouldn't have to build very many per year to meet USAF 'demand'.

The delta-V margin was *very* "tight" on this mission if SpaceX had
attempted recovery. Again, DOD didn't want to take any chances on
something deemed critical for war-fighters.

Which begs the following question: If Falcon9 is underpowered, and has
no margin for a high percentage of launches, was there much of a point
is making it re-usable?


The question is stupid because the premises on which it is based are
bull****. Falcon 9 is 'underpowered' for a very small percentage of
launches and it was always planned that that small number of missions
would be performed by expendable Falcon 9.

In the future, I wouldn't be surprised to see a GPS III (in a similar
orbit) launching on a Falcon Heavy with both boosters and the core
recovered. But we'll see.

If Falcon Heavy becomes popular, does SpaceX "convert" 3 flown stages ?
Or does it build new centre core but converts existing Falcon9s into
side boosters? or build the 3 from scratch ?


Yes.


We've told you repeatedly that it's the *inclination*, orbital altitudes
(apogee and perigee), and the mass of the GPS III satellite *combined*
that caused Falcon 9 to have very little margin for recovery on this
mission. You keep ignoring the *inclination*. You CAN'T DO THAT!

And when I asked how much of a difference it was launching from 28°
towards 55°, versus launching due east at 28° and then correcting to get
to equatorial orbit, you gave no answer.


Go do the math, as you were told to do. Your question is irrelevant
because you're confusing 'geosynchronous' with 'geostationary'.


--
"Ignorance is preferable to error, and he is less remote from the
truth who believes nothing than he who believes what is wrong."
-- Thomas Jefferson