"Mark Fergerson" wrote in message
news:xg1qe.5643$6s.3196@fed1read02...
Jeff Findley wrote:
"Mark Fergerson" wrote in message
news:hyXpe.5626$6s.252@fed1read02...

At our current level of technology, any conceivable effort
expended in human-presence space exploration simply won't return
more than the investment because humans have to carry along with
them bulky, complex, _expensive_ life-support hardware. Meanwhile,
we look through bigger and better telescopes, send robotic avatars,
etc. _because they don't need life-support hardware_.

This is wrong. What's holding us back isn't the "mass of the life
support
hardware", but the high cost of launching *anything* into space. When
costs
are in the $10,000 per lb to LEO range, *everything* you launch costs a
lot
of money.

I just love it when critics contradict themselves:

The fact is that on exploration missions like Apollo, people did far more
exploration and sample return than all of the unmanned missions combined.
Even today's Mars rovers move at a snail's pace on Mars, far slower than a
man in a pressure suit could move. The cost to benefit ratio is debatable,
because the "benefit" is currently something that can't be easily expressed
in terms of dollars. One can easily pick a definition of "benefit" that
makes either a manned mission or an unmanned mission look better.

Only when the benefit can be expressed in dollars will we be able to
determine whether man or machine is the better tool in outer space
exploration.

What's needed are new vehicles...

Did you not read what I wrote? Did you miss the part about "our
current level of technology"?

New technology is not necessary. It looks like Space-X is going to be
producing cheaper launch vehicles than the usual suspects with little in the
way of new technology. It's the design philosophy of luanch vehicles that
needs to change, not the technology.

There's an old SF short story along these lines; _The Cold
Equations_. Read it.

You're not doing much better than the original poster. Old sci-fi isn't
usually the best place to look for an explanation of why spaceflight is
so
expensive.

Ever actually read _The Cold Equations_?

Not yet, but I am familiar with the book. There are a few good web sites
that talk about the book. For example:
http://home.tiac.net/~cri/1999/coldeq.html

If you take DC-X as an example, the cost estimation equations NASA uses to
estimate program costs predicted a far higher cost than the actual program
cost. Note that there was little in the way of new technology in DC-X.
Most of the components were either "off the shelf" or were straight forward
(new) designs using existing technology. Those equations contain many bad
assumptions and are not bound by physics so much as institutional inertia.

Jeff
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