In article , lid
says...

On 29/12/2011 5:45 AM, bob haller wrote:
every ounce saved is greater payload capacity and less cost per
pound
to orbit....


The first bit is true, but the second not so much. If we assume the goal
is lowest cost per pound to orbit, then this may be achieved by using a
bigger vehicle with a lower payload fraction. Trimming ounces is not
always the best solution.

Agreed. Trimming ounces is one of the reasons that "space certified"
hardware is quite a bit more expensive than other "off the shelf"
aerospace hardware. Largely avoiding the trimming ounces problem makes
the hardware cheaper. Also, "throwing mass" at a problem is not unheard
of, but it's awfully painful to do when the payload is mass constrained.

But bigger launch vehicles isn't the only way to avoid trimming ounces
on payloads. In orbit refueling and/or assembly are other ways.
Neither have been used commercially, but they're certainly possible.

Jeff
--
" Ares 1 is a prime example of the fact that NASA just can't get it
up anymore... and when they can, it doesn't stay up long. "
- tinker