Of Reusable and expendable things..

There seem to be so many contradicting views about the reason the Shuttle is
so costly, and its hard to get through the 'noise' in all the camps with
opinions, but not many facts.

So, is it really cheaper to segregate people and the items they are to work
on in orbit.

Putting aside the argument for and against the ISS, its there now)

With modules like Leonado, and the way the trusses have been designed, could
either of these, or new modules be launched by expendables?

If you built a capsule system for the ISS, would you make the re entry
module re usable, or at least refurbishable, or throw away?

The big question is, is it actually cheaper to make expendable launchers,
even when you are throwing a lot of stuff away, to end its days as scrap or
burnt up or at the bottom of the sea?

Why is it less than cost effective to reuse the boosters of the Shuttle?

Is the cost basically in the labour involved in doing Shuttle maintenance
etc, against the continuous production of expendables?

Also, what about environmental effects of dumping junk in various parts of
the world in this manner?

Lastly, presumably, if the Shuttle does have to stop soon, and Progress is
the main supply system, or an equiv from Europe, this de orbit idea seems
to once again have some pollution implications. I have seen no mention of
this aspect, but presumably, heavy metals and goodness knows what else may
make it back in a way that can pollute the sea they land in. Not seen anyone
mention that.

Ok any answers to these questions that are not just from personal opinions
etc?

Brian

--
Brian Gaff....
graphics are great, but the blind can't hear them
Email:
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"Brian Gaff" wrote in message ...
There seem to be so many contradicting views about the reason the Shuttle is
so costly, and its hard to get through the 'noise' in all the camps with
opinions, but not many facts.
....
The big question is, is it actually cheaper to make expendable launchers,
even when you are throwing a lot of stuff away, to end its days as scrap or
burnt up or at the bottom of the sea?


Study after study has shown that the answer is "It depends".
It depends mostly on the launch rate. If the launch rate is
low (the threshold is usually determined to be less than a
few dozen launches per year - but it depends on the specific
vehicle design), than it is cheaper to fly expendables.
Reusable vehicles only pay off if the launch rate is high
enough for expendable hardware costs to exceed reusable
refurbishment costs. Historically, launch rates have never
exceeded the payoff threshold for a specific vehicle - although
the Soviets may have come close during the 1980s when they
launched close to 60 Soyuz/Molniya rockets per year.

Why is it less than cost effective to reuse the boosters of the Shuttle?


Because the shuttle flight rate is below the break-even
threshold. The booster casings have to be recovered, towed,
cleaned, dissasembled, stripped of residual propellant and
insulation, tested, measured, and shipped again. A new
casing, by comparison, simply has to be manufactured, tested,
and shipped.


Also, what about environmental effects of dumping junk in various parts of
the world in this manner?


Sunken shipping (and aircraft for that matter) out-mass the
stuff that has/will reenter from space so extremely much that
the space stuff is practically irrelevant. Some of that
sunken shipping (submarines) took nuclear reactors and
thermonuclear warheads down to the bottom of several oceans.

- Ed Kyle