JF Mezei wrote on Sun, 30 Dec 2018
12:24:31 -0500:

On 2018-12-30 10:27, Jeff Findley wrote:

This is the very first of the Block III satellites. They include many
improvements to prevent jamming, improve accuracy, and etc. And, since
this is a DOD satellite, perhaps this block includes other "features"
that aren't openly discussed that are critical to war-fighters.

That satellite covers only a relatively small part of the planet at any
point in time. may or may not cover Iraq on a particular day if humans
on ground would need whatever new features this SV gives.

So a single GPS satellite can't be "critical" in giving new services
because troups can't rely on it being visible in the sky where and when
they need it.

What is critical is to validate the design ASAP so more satellites can
be launched, at which point, whatever additional features they offer
have better odds of being over troiups when they need those features.


Let me try it in small words. EVERY launch until you have a minimum
Block III configuration up is 'critical' because you have a time where
you plan to fan out end user equipment that uses the new capabilities.


Suspect all you want. DOD disagrees with you. I'll side with DOD on
this one.

This could simply be a PR designation because it is an important launch
needed to validate the new SV before they give green light to launch the
rest of constellation.


Or they could mean exactly what they say and you could be being an
idiot. I find that probability more likely.

This makes zero sense. Check when SpaceX won this contract. Also, ULA
didn't even bother bidding on this one (DOD made a *huge* stink about
that).

The way I had read the article you linked to, ULA didn't bid because it
got the contract without any open bidding process, and SpaceX sued. The
end result is that SpaceX got the contract.

I obviously read that wrong.

Also, check the date when SpaceX won this contract. How far along was
SpaceX with landings and reuse? Please put some facts into your
"reasoning".

Fair point.

If you had a quote from Shotwell with an actual date, that would hold
*far* more weight than a Tweet or offhand comment by Musk. Musk knows
where he wants to go, but hard schedules are clearly not his forte.

Then perhaps next time I am doubtfull of what Musk says in a tweet, get
McCall to stop insulting me to no end because he believes every word
Musk says in a tweet.


Stop being a ****ing idiot and I will stop calling you one. You get
no special immunity from being called a fool merely because you happen
to be one.

Production, however, will absolutely continue for some time to come
because BFR/BFS hasn't even started flying, let alone proven itself yet!

The argument had been made that reusability would allow SpaceX to
continue Falcon9 launches with a relatively small number of built
stages, hence ability to stop production before BFR/BFS is flying.


And that argument is true for a sensible definition of "relatively
small number".


At this point, SpaceX doesn't yet know how many flights a Block 5 can
make, and the introduction of DoD as a customer changes the equation if
they require new stages.


SpaceX has a pretty damned good idea of where the lower threshold is
for number of reuses before major refurbishment is required. The
'equation' doesn't particularly change, since it's always been an
assumption that some launches will require expending the vehicle.


And requiring that the DoD stages have no legs/fins goes one step above
requiring a new stage. A new stage with legs can land and be re-used by
other customers. So the cost per launch is lower. But requiring a new
stage be ditched puts that launch on equal footing with ULA and others.


You're obviously too thick to understand WHY a vehicle would be
expended on a launch. It's not arbitrary. And if you have to expend
the vehicle, why would you throw away perfectly good parts? Save
money and don't put them on in the first place.



The point is that all of the research and development teams are now
focusing on BFR/BFS.

With BFR/BFS much farther into the future that originally marketed, ...


Cite? I think it will slide, but I don't see SpaceX moving the
schedule "much farther" to the right.


... I suspect there is still R&D being done on the Falcon9.


As I've noted before, you seem to "suspect" many silly, counter
factional things.


For one thing,
they still haven't determined how many times a block 5 can refly, and I
am pretty sure they will still be making fine tuning adjustments to it
as they gain experience with more and more reflights.


Neither of those requires "R&D". You obviously don't know what that
phrase means (either).


If the Falcon9 remains in production for longer than Musk had originally
announced, ...


Since Musk didn't announce a date, this would be a neat trick.


it likely means the whole team remains fairly big.


For some definition of "fairly big" that doesn't include a lot of
engineering folks.


It also
means the tooling to make engines etc needs to remain attached to
Falcon9 production instead of being moved to the BFR/BFS production.


What common parts do you think there are between Falcon 9 and BFR/BFS?
Given the lack of common parts I doubt this is an issue.



That's precisely why we keep seeing substantive
changes to the design, because the engineers are actually putting a lot
of R&D effort into the design.

When Musk made the original announcement, he made it look like this was
a validated design ready to be built and would fly soon. Now we find
this was just fancy dream on a powerpoint presentation and that
engineers are only now starting to see if this is feasable.


Musk never made the claim you say he did and we certainly did NOT find
what you think you've found. THIS is why you get 'insulted'; you
persist in saying incredibly stupid and wrong-headed things.


What this tells me is that Falcon9 will remain the mainstay for SpaceX
for some time to come and it isn't clear to me that BFR/BFS will end up
being as big/performant as the original powerpoit presentation made it
out to be.


For some definition of 'some time', certainly. Why would anyone think
anything else? Certainly not from anything anyone has actually said
to you. As for what "isn't clear" to you, this is just the flip side
of you "suspecting" remarkably stupid and counterfactual things; you
also 'doubt' many obvious things because they're not happening next
Tuesday.



If I were an engineer, I'd use the same material in the first stage just
for the commonality. But who knows. Maybe they'll stick with
composites because the first stage really doesn't experience much
heating on reentry because it's staging at suborbital velocities.

A heavy steel second stage reminds one of the Space Shuttle which had to
lug the mass of its wings and SSMEs all the way to orbit.


Well, no, it doesn't.


I wouldn't be surprised if BFR/BFS ends up with a reusable heavy crewed
second stage, and a light, disposable 2nd stage for cargo/satellites.


I would be, but then experience shows us that I have a somewhat better
connection to reality than you do. I think the original plan back in
the dark ages may have looked something like what you describe, but
the 'cargo' version was dropped, leaving only the 'Starship' version
and a tanker version. The cargo version could certainly come back,
but I think it's not as likely as you think it is.


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