View Single Post
  #9  
Old October 24th 17, 08:00 PM posted to sci.space.policy
Fred J. McCall[_3_]
external usenet poster
 
Posts: 10,018
Default Were liquid boosters on Shuttle ever realistic?

JF Mezei wrote:

On 2017-10-24 02:08, Fred J. McCall wrote:

Nice of you to finally figure that out. Falcon 9 Expendable (no
recovery of first stage) can manage just short of 23 tonnes to LEO.


There is one problem with Falcon 9 arguments: unlike NASA, SpaceX is
driven by business decisions. Get a limited payload at lowest possible
cost up there, and that includes getting up and running with the lowest
R%D costs possible.


A payload of 23 tonnes is not exactly considered 'limited'.


Musk admitted that at the time of their first succesful launch, they had
runned out of money and it would have been their last launch had it failed.


Yeah, that was Falcon 1 with a lot more limited payload, too.


And once you have an assembly line spewing out Merlin engines, and your
demand for engines goes down as you start to re-use Flacon 9s, it makes
business sense to use Merlins for your Falcon Heavy since you already
not only have a tested design, but also the assembly lines runnning.


There is no such thing as assembly line production 'spewing out'
rocket engines. It made sense to use Merlin engines because the idea
was to have three identical cores for Falcon Heavy, sort of like what
Delta IV Heavy does. In the event, Musk found they couldn't do that
and that they couldn't just use three Falcon 9 cores for Falcon Heavy.
The side boosters are now different from the central 'core'.


It does not necessarily mean that it is the optimal design from an
engineering point of view. It's the design that makes the most business
sense.


It may not even be that. Certainly no one here is advocating 'optimal
engineering design' as a GOAL, although that usually makes the most
business sense.


My sense is that the Shuttle was started, much like the Apollo program
with a "the sky is the limit, innovate, don't worry about budgets" only
to find that budgets were limited and had to compromise.


Sense seems to be something you lack. Like most big technical
projects, the original estimates were woefully low. Everyone tends to
underestimate the cost of dealing with the 'known unknowns' and of
course there's no budget at all for the 'unknown unknowns'.


The reason I asked the original question was to get a feel for what
could have been possible back in the 1970s had such budgets not been
limited and NASA be able to develop a Shuttle with engineering in control.


Find some of the discussions of the original Shuttle design.


--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw