Terraforming Venus

[Cray]

The big, obvious questions about terraforming Venus seem to focus on its atmosphere and producing oceans. However, a couple more questions occurred to me.

1) Say you've spun up Venus to a 24-hour day. Earth's spin causes some oblateness, while Venus has none. So...what sort of earthquakes and volcanic activity do you get when Venus starts plumping up its equator, and how long does that last? You're warping planet-sized masses of mantle and core. It seems like there'd be a lot of heat generated from that process.

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?

[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).

[stevebowers]

I'd like to write up a Venus-like planet with a continuous habitable ring suspended in the atmosphere above the equator; this ring could be extended over time until it covers most, or all of the planet. Paul Birch suggested that a habitable surface of this kind would shade and cool the lower atmosphere and would eventually settle down onto the planet's surface.

[Rynn]

I'd like to write up a Venus-like planet with a continuous habitable ring suspended in the atmosphere above the equator; this ring could be extended over time until it covers most, or all of the planet. Paul Birch suggested that a habitable surface of his kind would shade and cool the lower atmosphere and would eventually settle down onto the planet's surface.

I find the idea quite cool. A sophont in orbit might quickly glance at the planet and perceive it like a terraformed world with plenty of islands separated by odd coloured oceans[1]. Closer inspection though reveals that the oceans are huge banks of clouds and the islands vast platforms.

[1] Tap dancing past how exactly they got into orbit without knowing where they're going

[Cray]

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?

Venus has 4.8 × 10^20 kg of atmosphere to shed. Sequestering some CO2 as limestone and coal or hydrocarbons keeps carbon available for the ecosystem's carbon cycle, but there's still plenty of CO2 and nitrogen to shed.

Basically, you're asking for about 400m/s imparted to 4.87x10^24 kilograms but not evenly. If my understanding of rotational inertia isn't too completely decrepit (it probably is), then that's equivalent to accelerating the full mass to 160m/s.

With 4.8x10^20kg of reaction mass available you could get 173m/s at a specific impulse of 180,000. That's well within conversion drive capabilities and leaves plenty of room to compensate for losses, like trying to blast the exhaust through the atmosphere without using vacuum nozzles or something similar.

Crash thousands of relativistic kinetic rounds into it or directed boost bombs?

To get Earth-sized oceans, you need to import about 1.4 × 10^21 kilograms of water. Falling at Venus's escape velocity of 10.5km/s (a minimum), and assuming perfect conservation of momentum, and assuming perfect dedication of that momentum to spin, you'd get...3m/s. Hmm.

Alright, ocean delivery won't help much.

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.

I was thinking of a von Neumann project to drill wells / heat pipes several kilometers deep across the entire planet to a density of several wells per square kilometer. Compared to the resculpting of continents done to New Earth in the Terran Federation, that shouldn't be too hard. And based on geothermal power plant depletion rates that should cool the upper crust within a century.

The planet would be ideal for geothermal power after terraforming, though.

When it comes to planets like Venus it would be easier to colonise with bubblehabs than terraform.

I'm familiar with Landis Habs but I wanted to go old school on this. The end users would be a low technology (not lo tek) civilization.

[Drashner1]

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?

All of these and similar have been proposed at one time or another (although the ideas used fusion rockets rather than conversion). When I was in college, the science library on campus had back issues of the Journal of the British Interplanetary Society available - I spent many happy hours reading them Papers on most of these ideas could be found in one issue or another.

When it comes to spinning up Venus, some proposals look at only taking it up to a 96hr 'day' (48hrs of day, 48hrs of night) to make the process a bit easier.

Paul Birch has suggested that mass beam tech could spin up Venus in around 30yrs.

In terms of cooling the planet, I've seen a paper that suggested that a big soletta might freeze out the atmosphere (for easier packaging and removal) in around a thousand years or so. Although I wonder if you would need to get it down to freezing or could manage just getting it down to a temp that nanomachines/gengineered lifeforms could survive and start consuming the atmosphere and turning it into other stuff (more of themselves, rocks, packages for shipment offworld, etc.) Might be faster. Although my sense is that, at least in OA, terraforming is done more for fun or because people think it's a good thing to do rather than for any pressing need.

Todd

[radtech497]

It may not be necessary to increase the rotational velocity of Venus, if a suitable array of sunshades and reflectors can be established in Cytherean orbit. Since the object of increasing the planet's rotation is to avoid overheating the surface by exposing it to solar insolation for too long, simply regulating the amount of solar radiation reaching the surface, and where that radiation falls, at any particular time would achieve the desired result without having to resort to fusion engines, mass beams, or any other "active" technologies.

As far as cooling the surface is concerned, Carl Sagan's 1961 proposal using genetically modified algae could probably work (though at least several centuries would be required). An interesting article listing several proposals is here.

Radtech497

[Rynn]

All of these and similar have been proposed at one time or another (although the ideas used fusion rockets rather than conversion). When I was in college, the science library on campus had back issues of the Journal of the British Interplanetary Society available - I spent many happy hours reading them Papers on most of these ideas could be found in one issue or another.

When it comes to spinning up Venus, some proposals look at only taking it up to a 96hr 'day' (48hrs of day, 48hrs of night) to make the process a bit easier.

Paul Birch has suggested that mass beam tech could spin up Venus in around 30yrs.

Sounds like library time well spent hmm, yeah after I posted it it occured to me that it's not so outlandish (as you and Cray have pointed out). The 96h day point is interesting as well, given OA bioengineering in many cases populations might decide to "meet in the middle", as either a practical or just aesthetic compromise. Personally I've always thought it would be cool to have a longer day, 24 hours just never seems like enough.

In terms of cooling the planet, I've seen a paper that suggested that a big soletta might freeze out the atmosphere (for easier packaging and removal) in around a thousand years or so. Although I wonder if you would need to get it down to freezing or could manage just getting it down to a temp that nanomachines/gengineered lifeforms could survive and start consuming the atmosphere and turning it into other stuff (more of themselves, rocks, packages for shipment offworld, etc.) Might be faster. Although my sense is that, at least in OA, terraforming is done more for fun or because people think it's a good thing to do rather than for any pressing need.

Agreed on both points, presumably OA tech could overtake simple things like this through more advanced interventions. In terms of terraforming I think that's really the only reason why anyone in OA would do it. Aside from cases where it might be due to extreme ideological/political motivations (like Mars) there's really no reason to terraform when megascale habs can be built. Unless of course you feel like doing it.

Given OA automation it could be a very fun and communal thing to do rather than anything of significant effort. For example: the population of a hab might decide to terraform and move to a nearby planet. They have the templates for a variety of biospheres so they could just fab up the seed units for a terraformer swarm and just wait, but instead make it a public competition. They announce a deadline of one year to submit a concept piece for the ecosystem (basic biochemistry, major taxonomy etcetera). After that there's a period of advertising and a public vote. Then anyone is free within the year after that to design a neogen within the scope of the winning concept (like how we all contribute to OA). At the end of that it's all fed into a biosphere design program (that adds leaves to the branches and figures out how to incorporate everyone's designs) which then coughs up a template to put into a swarm.

Ten years later it's colonization day for the universally contributed to world

[Cray]

Given OA automation it could be a very fun and communal thing to do rather than anything of significant effort. For example: the population of a hab might decide to terraform and move to a nearby planet. They have the templates for a variety of biospheres so they could just fab up the seed units for a terraformer swarm and just wait, but instead make it a public competition. They announce a deadline of one year to submit a concept piece for the ecosystem (basic biochemistry, major taxonomy etcetera). After that there's a period of advertising and a public vote. Then anyone is free within the year after that to design a neogen within the scope of the winning concept (like how we all contribute to OA).

I like that. And it explains how the fjords of Africa won an award.

[Drashner1]

You could actually do more than 'merely' terraform (transform the environment of a planet to make it habitable). You could (as was done on New Earth) sculpt the surface in all kinds of ways. Some might be related to terraforming (a mountain range just here will cause rain to fall over there and move the jet stream a few degrees thataway). Some might just be for aesthetics (the Grand Canyon is considered quite pretty by many).

This might be done with nanobots, but in many cases might be achieved using armies of bots of all sizes, including some of near mountain scale themselves. That might be interesting to see

Todd