Terraforming Venus

[Rynn]

1) Say you've spun up Venus to a 24-hour day.

Man that would be a huge challenge even for OA tech (in terms of time at least). I'm not even sure how it would be done; conversion drives all over the surface anchored deep into the crust? Trillions of gravity tractors put in orbits that cause them to slingshot around the planet by the billion? Crash thousands of relativistic kinetic rounds into it or directed boost bombs? Whatever way I expect it would take a long time. If you can do that I doubt you'd be particularly worried about the earthquakes, you could use megascape cooling loops to bleed off heat from the crust and solidify it.

2) Venus has spent a bajillion years baking its crust at 900F, meaning its crust and mantle temperatures start at 900F and keep climbing toward the core. This is a huge heat reservoir that would be awkward for Earth-like oceans and terrestrial soils atop it. So, how much cooling does the crust need and how deep should you go with crustal cooling efforts to avoid boiling off the terrestrial environment? Would a few hundred meters provide enough insulation or should you go through the whole crust? Also, how would Orion's arm arrange cooling for entire, extant planetary crusts?

OA tech can manage it but it takes thousands of years to cool the world:
http://www.orionsarm.com/eg-article/49a3ee435bd98. I'm not sure if it would be needed though (at least for that long). If you sorted out the atmosphere (solar shade, megascale carbon sequestration) the heat might radiate out very quickly. The dark side of most planets get very cold, even if they have atmospheres. Earth is an exception because we have massive oceans acting as heat sinks.

When it comes to planets like Venus it would be easier to colonise with bubblehabs than terraform. Between 50 and 65km above the surface Venus's atmosphere is very Earthlike: similar pressure, 21% oxygen/71% nitrogen etcetera. I imagine OA tech could even go one better and construct giant platforms at this level. The supports would have to be very resistant to acidic environments but that shouldn't be too hard (and they could always self repair).