In article ,
says...

On 2019-09-15 10:32, Jeff Findley wrote:

Nope. Starship is the most technically challenging. A good program
manager focuses on retiring risk. Put another way, Starship is the long
pole in the tent for the launch vehicle, so it needs to be started on
first.

Fair point.

Fai to assume that the Raptor engine(s) being used for "hopper" tests
are really BFR engines with sea level engine bells/configurations?

Yes. All Raptors so far are all sea level. They don't need a vacuum
optimized engine yet. Eventually I'd expect them to put some vacuum
engines on Starship, but they'll still need sea level engines too, for
landing on earth.

I had been told that Musk intended to fund development of this "system"
by using it to launch commercial payloads including his own Starlink.
So I would have assumed BFR readyness would be higher priority.

Super Booster is needed for orbital flight. But so is Starship. It's a
TSTO system, not SSTO.

The "hopper" prototypes may be shaped and pitched as Starship
prototypes, but in my opinion their build quality points to them being
more generic prototypes than Sharship prototypes.

Aka: a test bench to test engines and other components as opposed to
being the "ship" prototype.

Hopper is the only vehicle as you describe. The two Starship prototypes
being built may not look pretty, but then again neither do most aircraft
that have mirrored surfaces when you get up close to them. Their skin
is "wrinkly" as well. People keep looking at the wrinkles in the
prototype Starship's skin and think that's somehow "sub-par". It's not.
They're mostly propellant tanks. They have to work properly, pretty
simply isn't necessary for proper operation.

and flying a Super Booster without a Starship on top is kind of
pointless.

Has the cargo version of Starship been finalized? I read "cargo door".
Are we talking single door, two doors like on Shuttle? And how will
satellites be launched form inside Starship? similar system to when
Shuttle launched satellites? Are are springs enough to push the
satellite out of the belly and into its final orbit?

Now you're asking about details only SpaceX knows.

Any chance that early cargo launches would have BFR on top of which are
recoverable fairings and single use conventional stage2/payload ?

Extremely doubtful. What you're describing is how Falcon operates. The
pitfall is you're throwing away a very expensive upper stage with every
flight. Full reuse is the entire point of Starship/Super Booster. That
an in orbit refueling allows Starship to travel to the moon, Mars, and
perhaps other places as well.

Hexagonal heat shield tiles. Starship Hopper flew with some of them
attached near its base.

Not going to happen. Shuttle tiles needed an obscene amount of
inspection and maintenance between flights.

Had the shuttle been rolled out the day before launch, would this
maintenance have been dramatically reduced compared to having the
shuttle out on the beach for weeks prior to launch?

Possibly, but given how humid and unpredictable Florida weather can be,
it would be a really bad idea anyway. Pop-up thunderstorms are a thing.

And where tiles will be used on Starship, what material now exists to
allow for re-usablility/quick turn around and is light? I was thihking
the odds are this will look a lot like what the shuttle used (but
obviously machined to different sizes/shapes)

Again, you're asking about details only SpaceX knows.

Or is it expected that a landed Starship will have to go through a
maintenance cycle that will "refresh" the heat shield?

Again, you're asking about details only SpaceX knows.

SpaceX is a private company. They have trade secrets.

Jeff

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