In article ,
says...
David Spain wrote on Fri, 14 Dec 2018 23:49:01
-0500:

On 12/10/2018 1:39 PM, Fred J. McCall wrote:
Well, that would be cost/schedule. Given his wording about "heavy
metal" I don't expect it will be the 'conventional' metal. Back in
the dim past around here there was a guy who proposed using swaged
steels for booster construction of a 'Big Dumb Booster'. There was
some weight penalty over 'conventional' materials, but he calculated
that it was not as much as you might think and that construction costs
would be much lower.


Speaking of dim past... Here's a gem from Paul D. reposting a passage
about Robert Truax from Ed Regis on Thor vs Agena.


You know, I've been saying something similar to the 'small vehicle for
people, big vehicle for cargo' thing for a years. Glad to see someone
collected data to back that up. Musk seems about to disprove the
whole thing, though, if he makes BFR/BFS work.


BFR/BFS is going to be pretty complex since it intends to be fully
reusable. That's going to drive up the cost to build it as well as
making it challenging to make it "safe" (more things to go wrong).
Commercial Crew is supposed to have a reliability of 1 failure in 250
(if I remember correctly) and both SpaceX and Boeing are both struggling
to satisfy NASA. If BFR/BFS is an order of magnitude safer than that,
it would make for an impressively safe crewed spacecraft and I'm sure
NASA would be very happy to fly crew on it.

That said, I'm personally skeptical of the claims that this first
generation fully reusable TSTO will be safe enough for the FAA to
certify for point to point transportation on earth. If BFR/BFS does an
order of magnitude better than commercial crew's requirements, I'm
really not sure the FAA would consider that "safe" when the alternative
is far safer (i.e. large passenger jet aircraft with modern turbofan
engines).

I think it far more likely that BFR/BFS would be certified for taking
people into space and back since the FAA requirements for that are far
less strict than for passenger jet aircraft. I'm thinking SpaceX is
going to try to argue that even as a P2P transport, it goes "into
space" and therefore shouldn't have to meet the strict safety rules that
a passenger jet aircraft would have to meet. I personally give this a
slim chance of actually happening.

Jeff
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