*From:* "Fred J. McCall"
*Date:* Sun, 09 Apr 2006 08:05:19 -0400

(Derek Clarke) wrote:

:I think an expendable LSAM saves cash!
:
:A reusable one would need a complicated restartable rethrottleable
:descent / ascent stage engine, whereas the ones planned for the
separate :ascent and descent stages are very simple and robust, hence
cheap.

Then why don't we use disposable cars and aircraft?

Expendables are only 'cheaper' because nobody has expended the capital
investment to design a 'reusable' set up for minimum operating costs.
Even the phrase 'reusable' implies there's a high turn-around cost. We
don't need 'reusable' vehicles; we need vehicles that operate like
planes, trains, and automobiles, with minimal maintenance other than
refueling between trips.

Planes have quite a high percentage of maintenance hours compared to
flight hours actually, and of course space vehicles are more demanding
yet.

While I agree in theory with the ideal of having completely reusable
vehicles, sometimes you just have to accept that throwing bits away is
the most economical course in practice.