In article ,
says...

Musk tweeted a picture of the crew access arm. It is very long.

No longer than the shuttle arm, because they're using the same fixed
structure on one side and the same flame trench on the other (so you'd
expect the Falcon launch vehicle to be on the same centerline as the
space shuttle).

So it would appear the tower will be at some distance from the rocket
itself.

Same as the shuttle.

Will be interesting to see how much of the "Shuttle" they are forced to
reproduce.

They're certainly reproducing much of the safety theater (as Fred called
it). Remember, this is the same NASA that initially thought shuttle
didn't need pressure suits on launch and landing and the same NASA that
didn't bother to even attempt to inspect the damage done to Columbia
while it was in orbit.

They're not especially good at putting "safety" in the right places, yet
they're "the experts" telling SpaceX and Boeing what to do. Cynical?
Yes, a bit. But, things that are different just aren't the same. Both
Dragon 2 and Starliner have zero-zero escape systems for the capsule
which shuttle obviously never had (shuttle had very large "dead zones"
where a significant failure *would* cause loss of crew.

For instance, the crew access arm for Shuttle could be brought back in
seconds to allow crews to egress in an emergency.

Seconds the crew wouldn't have if leaking hydrogen started burning. It
was a "feel good" measure put in place because there wasn't an escape
system on the shuttle.

Would this functionality be required or would the ability to jettison
capsule negate the need for "instant" emergency crew access arm rotation
back into position ?

Not sure what the sequencing will be. I'm sure SpaceX and NASA have it
all figured out.

One aspect to consider: in an aborted launch where something dubious
happened and they want emergency evac just in case, the crew access arm
and the zip lines (or even elevators) cause no damage to stack, do not
ignite anything. If it turns out to be a false alarm, they can releaunch
a day or two later after checks are done.

Then just sit in the capsule, just like one of the Gemini crews did when
the engines lit, then shut down. They should have ejected, by the
rules. But, they didn't feel the stack move, and ejecting carries its
own dangers, so they just sat there and waited it out. They made the
right call.

jettisoning the capsule at best destacks the rocket, at worse destroys
stage 2.

Better safe than sorry. Besides, you do know that Falcon 9 is a fairly
inexpensive to make, right? The pad is surely more valuable than the
Falcon 9 since any repairs on it delay the next flight.

Jeff
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