Terraforming vs O'Neills

From: phoebos@... [mailto:phoebos@...]

Lets take it a step further. If you have this large structure floating
around in space anyways, and a way to move it around, you could use it
as a solar parasol to shade Venus, and start a very long cooldown
process. Or you could use it to reflect extra light onto Mars, and warm
it up.

I'd say that well before the era when we're able to build thousands of miles
across or hundreds of miles across space mirrors, we'll be able to build
tens of miles across space mirrors, and thus will be in the era of the kinds
of space habitats proposed by Gerard O'Neill. And when we're to that point,
I predict the space settlers will look on the idea of trying to live on the
surface of a planet as somewhat backwards and disadvantageous.

A solar parasol might cool Venus down over the course of several centuries,
unless there are radical changes in atmospheric composition, which itself
might take several centuries of effort. Zubrin, after criticising O'Neill
for his assumptions concerning the practicality of large space mirrors, then
recommends solar mirrors for terraforming Mars not so much to warm it as
because he realizes the normal processes of photosythesis might take a
millenia to produce an atmosphere on Mars breathable to us. The extra
insolation might trim this down to a century or two.

I expect our space construction efforts to be turned to projects with
returns on much shorter timescales (at least within the lifetimes of the
people initiating the projects). This to me points to construction of
orbital habitats over any kind of planetary terraforming efforts.

Regards,

Mike Combs

From:
phoebos@... [mailto:phoebos@...]
Lets take it a step further. If you have this large structure floating
around in space anyways, and a way to move it around, you could use it
as a solar parasol to shade Venus, and start a very long cooldown
process. Or you could use it to reflect extra light onto Mars, and warm
it up.
I'd say that well before the era when we're able to build thousands of miles across or hundreds of miles across space mirrors, we'll be able to build tens of miles across space mirrors, and thus will be in the era of the kinds of space habitats proposed by Gerard O'Neill. And when we're to that point, I predict the space settlers will look on the idea of trying to live on the surface of a planet as somewhat backwards and disadvantageous.

A solar parasol might cool Venus down over the course of several centuries, unless there are radical changes in atmospheric composition, which itself might take several centuries of effort. Zubrin, after criticising O'Neill for his assumptions concerning the practicality of large space mirrors, then recommends solar mirrors for terraforming Mars not so much to warm it as because he realizes the normal processes of photosythesis might take a millenia to produce an atmosphere on Mars breathable to us. The extra insolation might trim this down to a century or two.

I expect our space construction efforts to be turned to projects with returns on much shorter timescales (at least within the lifetimes of the people initiating the projects). This to me points to construction of orbital habitats over any kind of planetary terraforming efforts.

Regards,
Mike Combs