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Old January 3rd 19, 01:47 PM posted to sci.space.policy
Jeff Findley[_6_]
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Default Falcon 9 Delivers Dragon Into Orbit, Flubs Landing

In article ,
says...

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?


No, they're validating their engineering analyses with, you know, actual
data from actual flights. Plus replacing a few parts here and there is
not at all the same as a complete tear-down and refurbishment, which is
what is planned after 10 flights.

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.


You don't know this because you don't know what the inspections have
found after the first, second, and third flights of the Block 5. SpaceX
is still a private company. They're not going to give away this sort of
information, especially when others are trying to copy them (e.g. the
Chinese and now India have both shown renderings that look very similar
to Falcon 9's first stage landing)

Saw a presentation by Mrs Shotwell on Youtube today. Basically, Musk
sets lofty goals and motivates employees to reach for the sky, but then
she and the engineers get to actually work out what goals can be
achieved and get the job done.


Yes. That's generally how businesses work. The guy at the top sets the
direction and the people under them does what it takes to make that
happen.

Aspirational goals set by Musk aren't necessarily what gets implemented
in the end.


That's a sweeping generalization. But, we're talking specifics here.

So just because Musk said 100 flights doesn't mean this is the actual
limit they will set. And if the max is 3 flights so far, they are not
even close to knowing what the limi9ts for "easy" reflight , "reflight
after major maintenance" and "likmit for reflights" are.


This reads like your opinion, not something Shotwell said. If you're
going to "name drop" primary sources, please directly quote them.

Specifically, in the video you saw, did Shotwell say that Falcon 9 Block
5 has failed to meet Musk's goal of 10 flights without refurbishment and
up to 100 flights with refurbishment? Be specific.

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. 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).


I personally think they already have "solid experience in reflights".

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.


The design goal is 100 launches total (with refurbishment every 10
launches), so using 10 as a "total launch limit" makes no sense.

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


And I'm not sure the number 100 has been decided. Reality will likely
be somewhere between 10 and 100 simply because BFR/BFS will likely
replace Falcon long before any booster reaches 100 flights.

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. Not standards based on empirical evidence since
they haven't even reached 1 stage with 10 re-uses yet let alone 100.
Not saying they won't achieve this, just saying there is no assurance
they will at this point.


True, but Musk doesn't just pick his aspirational goals out of thin air.
He's done a good job so far of picking goals that are actually
achievable, IMHO. To me that means he's listening to his senior
engineers and basing his goals on what is actually physically
achievable. So my guess sis the max number of flights of a booster is
closer to 100 than it is to 10.

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.


Fred gave you estimates of Falcon production capacity. Based on what
SpaceX can produce, they will have zero problem selling expendables to
DOD if DOD never certifies flights on flown Falcon boosters.

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.


True. And now that development is done, other customers have purchased
Falcon Heavy flights.

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.


Bull****. Again, SpaceX has the production capacity to sell expendable
Falcon boosters if that is what the customer wants. SpaceX will charge
a premium for this and will therefore still make a profit on an
expendable launch. I really don't see how this "changes the business
model" since Falcon production isn't anywhere close to shutting down.

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


Again, I don't see how. Falcon is not BFR/BFS. They don't share
production facilities. The only thing this might impact would be how
many people SpaceX has to have in manufacturing. Perhaps they'll need
to hire a few more people to build BFR/BFS instead of shifting people
from Falcon. But again, if they're charging more money for expendable
Falcon launches, they can easily cover that cost.

Hiring more people is a thing companies do. That bit isn't "rocket
science".

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'll simply charge a premium for expendable Falcon launches and
adjust manufacturing shifts and hiring accordingly. This is why
companies have managers, to manage things like manufacturing.

You're making a mountain out of a molehill.

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?


1. It's not underpowered.
2. It's got good margin for most flights (based on the number of actual
landings!).
3. GPS III was a heavy payload going to a high inclination medium orbit,
which is *unusual* compared to other launches. It was the exception,
not the norm.
4. Reuse is the next big step in lowering launch costs. Falcon is just
the first iteration. Everything learned doing Falcon will feed into the
development of BFR/BFS which is the second iteration of SpaceX reusable
launch vehicles. BFR/BFS is intended to be fully reusable.

BFR/BFS *is* the point. Musk has *always* wanted to send people to
Mars. You can't easily, economically, do that with Falcon.

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 ?


Falcon 9 first stage is identical to the Falcon Heavy side boosters.
The difference is one has an interstage and the other has a nose cone
and the side attachment points. Block 5 is literally designed so that
"converting" a booster from one to the other is a matter of bolting on
(or removing) the bits that are needed (or not needed).

Falcon Heavy's core is specific to Falcon Heavy since it has to carry
more load than a Falcon 9 first stage. So the more popular Falcon Heavy
becomes, the more Falcon Heavy cores will be built (again, they've got
the manufacturing capacity to do this).

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.


Others have already done the math. Both Fred and I have told you the
results (executive summary style) and you still don't want to believe
either of us.

Perhaps if you do the math yourself you'll understand.

Jeff
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