"JF Mezei" wrote in message
eb.com...

On 14-10-31 12:30, Greg (Strider) Moore wrote:

At some point the smart engineer will realize that making a disposable,
but
reliable engine doesn’t save you much in times of design costs or usage
costs.

For the engines, you are probably correct. At the powers/thrust
involved, any imperfection yields wear and tear that is fatal.

Ah, but one would argue that any imperfections that are fatal will be so
very early on in the program.

However,
the cost of recovering the engines may make the economics less
attractive when you consider you can only re-use the engine a certain
number of times, unless you get to something like an aircraft engine.

And that's exactly the point. We have to start thinking about them like
aircraft engines with extended meantimes between failure.

Design for success, not failure.


Anytime a launch is done near ocean, it means SALT WATER is involved in
recovering the engines for first or second stage. And SALT WATER is bad!


That is probably really ultimately the biggest single issue with recovery,
not the design itself.


At the end of the day, the Shuttle wasn't all that bad despite all the
criticism.


The Shuttle got a lot wrong, enough that it tends to overshadow what it got
right.

Frank Culbertson said that the failure costed them about $200 million
bucks. I am pretty sure that if the SHuttle had been operated
"commercially" instead of "by pork", they could have lowered the launch
costs to about 300 million.

Ultimately, two things killed the shuttle:
Massive overhead
Few flights

And both drove each other. The per cost flight of a shuttle was about $300M.
When you figure the price per pound, that's actually pretty damn good.
BUT, the overhead costs were damn high. They made the mistake (well it
wasn't a mistake, they knew what they were doing and had little choice given
the state of the art and the budget) of not designing it from the start for
the lowest possible turnaround.

Examples: LFBB, would have almost certainly ended up cheaper than SRBs (if
only to eliminate the requirement for two ships off-shore to recover the
booster) but would have cost a LOT more to develop.

Or work platforms and designing the orbiter itself for far easier
serviceability. Planned early on, but cost and mass limited it. Of course
they were huge on "mass to orbit overall". Musk is making the choice of
"cost to orbit". If you can only fly 1/2 the payload but costs you .49 as
much, you come out ahead.

Or replace the OMS/RCS pods with a non-hypergolic. Cheaper to service, cost
more up front, etc.

So yes, we already know from what was built it could have been cheaper to
fly.

Fortunately, Musk and others are learning the right lessons (perhaps the
most important one being design for cost up front).




--
Greg D. Moore http://greenmountainsoftware.wordpress.com/
CEO QuiCR: Quick, Crowdsourced Responses. http://www.quicr.net