renewable resources?

> My thought was that once a significant civilation has a presence in
> space, it is unlikely that there will be much material trade
> between them and a planet. Once most needed machinery can be
> manufactured in space, there is less need for importing goods up a
> deep gravity well. If the planet doesn't have goods needed by the
> colonies, why would the colonies continue to provide raw materials
> to the Earth?

There won't be high-mass-per-value stuff coming up, but there will be exchange even if it's just zero-mass stuff like tv shows, legal services, and tech support. As long as raw materials and sunshine are ultra-cheap in space, it will be cheaper for people in near-earth space to drop stuff down the gravity well and call tech support in India than to keep a bunch of people sitting at phones all day at home.

> This skips the possible issues of whether a planet would want
> hundreds of thousands of tons of raw (or lightly refined) materials
> to be brought into orbit each year for dropoff.

Unless some new species evolves, people will want whatever's cheapest and won't care much about the details and externalities.

--- In spacesettlers@yahoogroups.com, Matt Gallimore wrote: