In article ,
says...

On 2019-09-22 20:08, Greg (Strider) Moore wrote:

As Niklas points out there are multiple solutions that can easily solve
this.


Many solutions yes. But leaving this to the last minute may result in
your trying to fit a simple solution into a ship that was not planned to
handle it and require some serious engineering changes.

Agree to disagree here. Any solution is going to be constrained by the
structure and tank design. They're not going to make major changes to
the design that would do something like change the tank geometry.

Consider the function of lowering cargo pallets to ground. If you will
have some rail deploy out the door and then a crane be able to lift
cargo pallet from cargo floor, move to the outside and lower pallet
down, then that rail needs to have structural attach point that designed
at the right location. So when designing the structure of Starship, you
need to think of that. Not only to have structural elements where a rail
would need to be attached, but also to live without strucrtural elements
going through door frames.

That's a minor thing compared to, say, the structure needed to support
the winglets/flaps on the spacecraft. The loads on those during an
earth reentry are *very* high compared to rails/cranes/ladders/etc.
needed on Mars to lower cargo and crew to the surface (and back up
again).

And there is also the issue of testing pressurized doors that are larger
than humans have ever built (which are truly airtight and safe). Unless
they do CBM hatch sized doors for both human and cargo exits.

I'm pretty sure that the doors used for test facilities at NASA
installations would beg to differ. Especially those in Ohio. This
really isn't that hard of a problem. That's just straightforward
mechanical engineering.

If manned vs cargo Starships will have totally seperate setructures,

This is extremely doubtful. Everything from the base up to the top of
the propellant tanks would be essentially the same. Minor differences
might be introduced, but keeping them as close to the same as possible
means commonality which reduces production and maintenance costs.

then SpaceX can start to work on the cargo version now and only worry
about the doors needed to release satellites in orbit.

Obviously cargo Starship will be the first. They're not launching crew
in it on the first flight like the shuttle did. We very nearly lost
STS-1 and its crew on Columbia's first flight. That's a mistake no one
will repeat.

But when it
stats work on the manned version, it really needs to start planning ALL
the details of anything that would replace normal skin of ship as well
as punch large enough holes to force discontinuity in structural elements.

The upper portion of the Starships will necessarily be different
internally. But structurally, I have a feeling that these beasts will
be overbuilt by aerospace standards. Having a large factor of safety is
a "good thing" enabled by in orbit refueling.

So really early on in the ship's design, they need to think about
this.

Sure, internally. But being a private company means we're not privy to
such details unless Elon Musk himself decides otherwise.

This idle speculation is largely irrelevant given that Elon Musk is
giving us an update in a matter of days. Just wait a bit and I'm sure
he'll answer some of these questions.

Jeff
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