Roger Books:

Roger Books:
> I think I may have to argue this one. If you can't put stuff in the

Well, this is why I said you must be very careful with the exact balance.

And when I talked about reasonable stuff, I meant military equipment
(reasonable in the context). This would not preclude making a buck out of
shipping something more rare and valuable, e.g. "spice".

Go read Greg Costikyan's article "The 11 Billion Dollar Bottle of Wine"
at http://www.crossover.com/~costik/inttrade.html

It has a general piece, plus calculations for Traveller. Basically, he came to
the conclusion that it's not profitable except in
some rare cases -- *even* assuming the liberties Traveller takes with
the laws of physics...

There's also different kinds of shipping. E.g. it would be horribly expensive
to fly to Pluto *right* *now*, with current tech. But if you could magically
set up a base there, it could be reasonably inexpensive to launch chunks of
iron ore back here (yeah, I know ice, not iron, would be the most likely
export for Pluto...).

You want your troops and tanks there *intact*, and *asap*. Typically, they
also want to come *back* the same way. The stream of ore they're supposed to
be chucking back can take a bit of beating and doesn't mind if it's in transit
for 500 years or never goes home again.

And yes, this *does* mean that shipping plain leg infantry (at least until
good cryogenics are available) is just about as dumb a military move as you
can make. Humans take space, consume food air and water, are sensitive to
temperature levels, produce waste etc.

> Without interstellar commerce there is no real reason to be

Yes, this *is* a possible result. In fact, it is even likely at the first
stages of interstellar travel. The first colonies are very likely not to
be profitable for generations -- which ofcourse brings the question
who'd fund such a thing, which in turn brings the shadow of doubt over all
this interstellar stuff...

> To rephrase, if I can make money shipping food with a bulk hauler I

Err... stuff like food and basic raw materials are on the bottom rung when it
comes to profit per pound. It *is* highly likely that interstellar
shipping of them "old-style" (i.e. with a manned cargo ship) is not a
viable economic venture in any semi-realistic background. You don't see
much water shipped around the globe today, do you? Unless it's bottled with an
"Evian" sticker ofcourse...

The fact is, as we currently understand the world around us, the odds are very
much stacked against an interstellar culture. The odds are very much against
going en masse to *any* other planet, even the closest one.

One could just do some hand-waving, say it's a space opera and assume
the universe is just our old earth with different background paintings and
props. Nothing wrong with that, but if one goes down that road, one might just
as well throw out the remaining bits of realism with a little more PSB. Why
bother with ships? Just assume everyone teleports to combat. Why bother with
tanks and guns? Just assume all conflicts are peacefully settled in UN
assembly meetings...

Also, PSB is an insidous thing. It typically has holes, which you cover with
more PSB, which has holes of its own, which you cover with...

OTOH, if one wants to retain the suspension of disbelief, one must set the
limits. And those limits, being "laws of nature", affect *everything*,
including civilian traffic and trade, which in turn affects the reasons why
anyone would want to fight over West Bumfuck and with how much resources. It's
a vicious circle...