Inhabitable Planets Too Close Together?

I will concede your point about the difficulty of terraforming Venus type planets as opposed to Mars type planets. The later can be terraformed simplify dropping the right ratio of oxygen and nitrogen ices plus water. The colony ship's propulsion system can be used as a space tug.

I will also reiterate my point that unless Avery terrestrial planet sin system, the colonist would have to remain space based for a century or two while their population and industrial capacity increase to the point where they can terraform the planet. At this point that might notbewilling to do so. Alternatively, a second wave of colonists might arrive trading advanced technology for assistance in terraforming.

SWM wrote:I conceded right at the beginning that energy was not an issue. Nor am I concerned about volume of the gas, as such. I also already agreed that sufficient rate of gas flow can be achieved.

What you have not convinced me about is the idea that it would be possible to convert oxides into free oxygen at a rate of 1.2 billion tons per second, unless you already have a well-established industry at the planet. I could see those kinds of production rates for an entire well-populated highly industrialized planet, if it decided to concentrate on it. But we are talking about new planets with nothing on it except what the colonists bring along. I disbelieve it.

If someone really wanted to do it, and invested enough manpower and an industrial planet's GNP into it, and had the current Honorverse technology to work with, I will accept that it could be done. But there is just no way you will convince me that this was done as a matter of course during the major colonization period of the Honorverse.

crewdude48 wrote:

SWM wrote:If someone really wanted to do it, and invested enough manpower and an industrial planet's GNP into it, and had the current Honorverse technology to work with, I will accept that it could be done. But there is just no way you will convince me that this was done as a matter of course during the major colonization period of the Honorverse.

Well, the survey ships could bring along some. If they found a planet that could be colonized, but had no O2 in the air, they could have some sort of system they leave behind to begin the teraforming process. The system would then have hundreds of years to convert the system rather than dozens. This would allow them to both find more planets that they could sell, and sell each of the planets for a higher price due to increase in habitability.

And if they were von Neumann type machines, they could leave only one or two on each planet, and still have it much more livable than before the next wave arrived.

Side note: auto-correct really hates the words "von Neumann"

That is plausible, and many stories have been written with around that concept. It also moves the terraforming beyond "several decades". The text, unfortunately, doesn't suggest anything like that. I would have expected it to mention that the surveyors were initiating terraforming. Instead, it just says that they bring back information on systems they have surveyed. I interpret this to mean that the survey ships are not initiating terraforming, but there is enough ambiguity to allow the possibility.

A point to consider in any terraforming operation is what stage the planet is in. Is it volcanic or non-volcanic. Does it have high concentrations of sulfur? Does it already have water? Does it, in fact, have CO2 in the atmosphere? And will a slow boat colony know far enough in advance to bring the right organisms? Especially those like Grayson that left before hyperspace surveys became available?

namelessfly wrote:I will concede your point about the difficulty of terraforming Venus type planets as opposed to Mars type planets. The later can be terraformed simplify dropping the right ratio of oxygen and nitrogen ices plus water. The colony ship's propulsion system can be used as a space tug.

Actually, my point is just as valid for Mars-type planets as it is for Venus-types. Either way, you have to actually convert oxides from somewhere into free oxygen. Whether you do it in space and create comets or convert an existing atmosphere in situ or grind up rocks on the surface and extract the oxygen doesn't matter. You won't find useful quantities of free oxygen in space, on a comet, or on a planet, unless it has been generated by living organisms (as biological by-product or industrial action). You must create an incredible amount of oxygen to terraform a lifeless planet.

That's been my point all along. I haven't been discussing how you get the oxygen into the atmosphere, or where you get the oxides from, or what kind of atmosphere the planet has or doesn't have at the beginning. I'm just saying that to get this done in a few decades, you have to create oxygen from oxides at an incredibly enormous rate. This is true whether you are terraforming Venus, or Mars, or Titan, or the Moon, or primordial Earth.

I will also reiterate my point that unless Avery terrestrial planet sin system, the colonist would have to remain space based for a century or two while their population and industrial capacity increase to the point where they can terraform the planet. At this point that might notbewilling to do so. Alternatively, a second wave of colonists might arrive trading advanced technology for assistance in terraforming.

That's a reasonable idea. And it conforms with my premise that it is not possible to create a breathable atmosphere on a newly colonized planet within a few generations. There is nothing in the text to suggest that any Honorverse colonies started this way. But I will concede that it is possible that some colony has done this in the Honorverse.

Go back to my earlier post where I calculated the energy requirement for making the Oxygen. Given the ability to build a fusion rocket for a Colony ship, it is doable. It is just difficult to wrap your mind around the implications of fusion rocket technology. Even an interstellar colony ship propelled by a light sail would be able to massively alter a planetary environment

SWM wrote:

namelessfly wrote:I will concede your point about the difficulty of terraforming Venus type planets as opposed to Mars type planets. The later can be terraformed simplify dropping the right ratio of oxygen and nitrogen ices plus water. The colony ship's propulsion system can be used as a space tug.

Actually, my point is just as valid for Mars-type planets as it is for Venus-types. Either way, you have to actually convert oxides from somewhere into free oxygen. Whether you do it in space and create comets or convert an existing atmosphere in situ or grind up rocks on the surface and extract the oxygen doesn't matter. You won't find useful quantities of free oxygen in space, on a comet, or on a planet, unless it has been generated by living organisms (as biological by-product or industrial action). You must create an incredible amount of oxygen to terraform a lifeless planet.

That's been my point all along. I haven't been discussing how you get the oxygen into the atmosphere, or where you get the oxides from, or what kind of atmosphere the planet has or doesn't have at the beginning. I'm just saying that to get this done in a few decades, you have to create oxygen from oxides at an incredibly enormous rate. This is true whether you are terraforming Venus, or Mars, or Titan, or the Moon, or primordial Earth.

I will also reiterate my point that unless Avery terrestrial planet sin system, the colonist would have to remain space based for a century or two while their population and industrial capacity increase to the point where they can terraform the planet. At this point that might notbewilling to do so. Alternatively, a second wave of colonists might arrive trading advanced technology for assistance in terraforming.

That's a reasonable idea. And it conforms with my premise that it is not possible to create a breathable atmosphere on a newly colonized planet within a few generations. There is nothing in the text to suggest that any Honorverse colonies started this way. But I will concede that it is possible that some colony has done this in the Honorverse.

Use lightsail to to use sunlight for thermal dissociation of cometary ices then process through electromagnetic separation or distillation. Deorbit gases to rain on planet. Use lightsail to boil atmosphere to big enough temperature that big fraction of gas molecules are at escape velocity.

namelessfly wrote:Assuming that the gases in our candidate Carbondioxide atmosphere has an average heat of formation of about 10 megaJoules per Kg (someone will look it up), then ww need an energy input of 1eex23Joules.

We are assuming that this colony is being established by Weberverse STL technology where they have sent a colony ship massing perhaps 100,000 tons or 1eex8 Kg at 1/2 Cee, so the KE of the ship maxed out at 1eex24 Joules.

The energy input needed to terraform a planet is therefore on the order of 1/10 of the energy needed to send the colony ship,

I don't think the KE of an impeller-driven ship is a good gauge of the energy its power plant produces. If it were, ships would be mostly fuel space, and tankers would be prominent auxiliary vessels. For instance, there's a profile of an Mk16 missile in the back of Storm from the Shadows which shows that the fusion reactor, with whatever fuel it's got, takes up only about a fourth of the missile's volume -- even though the missile is capable of reaching a substantial fraction of lightspeed. For an extreme case, dispatch boats are capable of traveling for months without any mention of refueling, but try to estimate how much fuel their fusion plant consumes.

Good point.

The KE of Impeller driven ships is two or three orders of magnitude greater thantheenergy of the fusion fuel they could plausibly carry.

However; the early STL colony ships were fusion rocket powered.

However;

Bill Woods wrote:

namelessfly wrote:Assuming that the gases in our candidate Carbondioxide atmosphere has an average heat of formation of about 10 megaJoules per Kg (someone will look it up), then ww need an energy input of 1eex23Joules.

We are assuming that this colony is being established by Weberverse STL technology where they have sent a colony ship massing perhaps 100,000 tons or 1eex8 Kg at 1/2 Cee, so the KE of the ship maxed out at 1eex24 Joules.

The energy input needed to terraform a planet is therefore on the order of 1/10 of the energy needed to send the colony ship,

I don't think the KE of an impeller-driven ship is a good gauge of the energy its power plant produces. If it were, ships would be mostly fuel space, and tankers would be prominent auxiliary vessels. For instance, there's a profile of an Mk16 missile in the back of Storm from the Shadows which shows that the fusion reactor, with whatever fuel it's got, takes up only about a fourth of the missile's volume -- even though the missile is capable of reaching a substantial fraction of lightspeed. For an extreme case, dispatch boats are capable of traveling for months without any mention of refueling, but try to estimate how much fuel their fusion plant consumes.

namelessfly wrote:Assuming that the gases in our candidate Carbondioxide atmosphere has an average heat of formation of about 10 megaJoules per Kg (someone will look it up), then ww need an energy input of 1eex23Joules.

We are assuming that this colony is being established by Weberverse STL technology where they have sent a colony ship massing perhaps 100,000 tons or 1eex8 Kg at 1/2 Cee, so the KE of the ship maxed out at 1eex24 Joules.

The energy input needed to terraform a planet is therefore on the order of 1/10 of the energy needed to send the colony ship,

Bill Woods wrote:I don't think the KE of an impeller-driven ship is a good gauge of the energy its power plant produces. If it were, ships would be mostly fuel space, and tankers would be prominent auxiliary vessels. For instance, there's a profile of an Mk16 missile in the back of Storm from the Shadows which shows that the fusion reactor, with whatever fuel it's got, takes up only about a fourth of the missile's volume -- even though the missile is capable of reaching a substantial fraction of lightspeed. For an extreme case, dispatch boats are capable of traveling for months without any mention of refueling, but try to estimate how much fuel their fusion plant consumes.

namelessfly wrote:Good point.

The KE of Impeller driven ships is two or three orders of magnitude greater thantheenergy of the fusion fuel they could plausibly carry.

However; the early STL colony ships were fusion rocket powered.

However;

Part of that is made up by the energy siphon effect, which would not, of course, be available to terraformers.

Someone will correct me if I am wrong, but the early STL colony ships did not have impeller drive. They were fusion rockets with "hydrogen capture field" (Ram Augmented Fusion Rockets) that seemed to achieve a cruisig velocity of 1/2 Cee. The drag from the ram fields could be used foreffecienddecelleration. This coincides to a KE of about 1.16eex16 Joules per Kg which implies a mass ratio of 25:1. I can see this mass ratio being reduced by using Ram Augmented Laser Rocket. Given the politics described in BY THE BOOK, the Greens would have preferred to retain control of propulsion energy for initial boost.. However; the colony ship would have the capacity to generate somewhere on the order of 4eex14 Joule per kilogram.

How much does an early colony ship mass? Assuming ten tons per colonist and a minimal, plausible colony population of 10,000 people then you need a 100,000 ton starship or 1eex8 Kg.

Energy budget of the colony ship is then 4eex22 Joules.

Going back to planetary atmosphere of 1eex4 Kg per square meter and a planetary surface area on the order of 1eex8 square kilometers or 1eex14 m^2, the mass of atmosphere is on the order of 1eex18 Kg, so you have 40,000 Joules per KG to play with.


Getting back to some bruteforce terraforming ideas.

Need water, water ice extracted from comets using brute force thermal vaporization and destination.

Need to extract CO2, boil it off by using a lightsail to heat up selected regions of the atmosphere so that a large fraction of gas molecules achieve escape velocity.

Getting back to energy budget.

Assuming that colony ship has a 1,000 kilometer diameter lightsail to capture laser energy for Ram Augmented Laser Rocket.

This is a surface area of 1eex6 square kilometers or 1eex12 m^2 with a total power of 1eex15 Watts. Over a one year period that is 3eex22Joules delivered to the planet.

Screw chemical conversion of CO2 to O2 and hydrocarbons, just boil off the atmosphere and start over.

JohnRoth wrote:

namelessfly wrote:Assuming that the gases in our candidate Carbondioxide atmosphere has an average heat of formation of about 10 megaJoules per Kg (someone will look it up), then ww need an energy input of 1eex23Joules.

We are assuming that this colony is being established by Weberverse STL technology where they have sent a colony ship massing perhaps 100,000 tons or 1eex8 Kg at 1/2 Cee, so the KE of the ship maxed out at 1eex24 Joules.

The energy input needed to terraform a planet is therefore on the order of 1/10 of the energy needed to send the colony ship,

Bill Woods wrote:I don't think the KE of an impeller-driven ship is a good gauge of the energy its power plant produces. If it were, ships would be mostly fuel space, and tankers would be prominent auxiliary vessels. For instance, there's a profile of an Mk16 missile in the back of Storm from the Shadows which shows that the fusion reactor, with whatever fuel it's got, takes up only about a fourth of the missile's volume -- even though the missile is capable of reaching a substantial fraction of lightspeed. For an extreme case, dispatch boats are capable of traveling for months without any mention of refueling, but try to estimate how much fuel their fusion plant consumes.

namelessfly wrote:Good point.

The KE of Impeller driven ships is two or three orders of magnitude greater thantheenergy of the fusion fuel they could plausibly carry.

However; the early STL colony ships were fusion rocket powered.

However;

Part of that is made up by the energy siphon effect, which would not, of course, be available to terraformers.