[Spaceships] Million Merchant Marathon

[scc]

Originally Posted by Fred Brackin

I wouldn't move those quantities of nitrogen from Venus to either the Moon or Mars and I wouldn't use rocket ships in hohman orbits.

The best alternative I can think of off-hand is to move it from the moons of Neptune where its a solid and wrap it in enough aluminum (shiny side out) to keep it from melting and also provide the conductor necessary for use in a magnetic launcher.

Titan might also be an interesting source.

So I'm using Venus because I'm trying to terraform all three, Venus has too much atmosphere while the Moon and Mars have too little, either way I'm going to be moving that stuff off of Venus, might as well use to for these other terraforming projects as well.

Um, no rockets, either a mass driver to increase rotational speed to reactionless drives tailored to produce space fighters (They have a top speed).

Want liquid nitrogen because it's easier to handle (slightly)

EDIT:

Originally Posted by SydneyFreedberg

Can you terraform the Moon? I’d be surprised if it had enough gravity to retain nitrogen.

Atmosphere or lack there of is more a matter of capturing said atmosphere, Titan is only a bit bigger then our moon and has a greater atmospheric pressure then Earth.

Originally Posted by mlangsdorf

At TL9, does a 300,000 ton, SM+13 advanced fusion pulse drive system that costs $7.2 billion count as a family operated ship? Because it takes 1.2e10 trips by that kind of freighter to move that amount of nitrogen.

A cheaper, SM+10 version of the design only costs $240 million, so more family friendly, but requires 3.6e11 trips. Which is a crazy high number.

But I agree with Fred. It is going to decades, if not centuries, to move that much stuff, and there's no great reason to do it with manned (or even robotic) cargo ships. Build a ridiculously huge mass driver or laser launch system in orbit around Venus and send frozen N2 payloads to the inner system on ballistic paths.

First off, yes I realise about the time scale.

Using a pulse drive not only means fuel costs, which raises the cost of this whole program, which given that Earth will go through a dark age making fuel production impossible for part of this, is a big problem. Tt also goes my decision to use another method propulsion as the primary for this setting, one with some cool, or at least interesting, options.

[Fred Brackin]

Originally Posted by scc

So I'm using Venus because I'm trying to terraform all three, Venus has too much atmosphere while the Moon and Mars have too little, either way I'm going to be moving that stuff off of Venus, might as well use to for these other terraforming projects as well.

s.

It's obvious that nitrogen is desirable as an atmospheric dilutant anywhere they don't have it but what does isolating it on Venus and then getting rid of it have to do with the atmosphere of Venus? That's 95% carbon dioxide.

I've seen proposals that capture the carbon and turn it into many many miles tall cooling towers of diamonoid (pumping heat from the lower atmosphere to the upper where it is more easily gotten rid of).

You're probably going to need the nitrogen on Venus to make bio-mass when it cools enough.

By contrast the moons of Neptune are very unlikely to e terraformed and you can mine the solid nitrogen with cryogenic nanites or aomething like that.

[Anthony]

The simplest option for Mars is to head out to the Kuiper belt or Oort cloud (depending how patient you are; further out = less delta-V but more time) and start kicking comets towards Mars. Mostly what this will get you is water, but you need a thousand times more water than you need nitrogen, so the ammonia content of the comets should do the job.

Scooping up the atmosphere of Venus won't do you any real good, because it's not made up of the things you need anyway; it's mostly carbon dioxide, which isn't what Mars needs. Venus is a ridiculous mega-engineering project, far beyond the scope of Mars, but if you're really dedicated to doing it you want to deliver large amounts of water, re-spin the planet, restart tectonics so you can bury a lot of the CO2, and give the entire planet a sun shade. You might be able to start in on that by whacking it with a substantial planetoid, assuming you don't mind waiting a million years for it to be habitable.

[Agemegos]

Originally Posted by scc

Atmosphere or lack there of is more a matter of capturing said atmosphere, Titan is only a bit bigger then our moon and has a greater atmospheric pressure then Earth.

Titan is 48% larger than the Moon. On the other hand it is less dense. Taking one thing with another, Titan's escape velocity is 2.64 km/s, whereas the Moon's is only 2.38 km/s. That's a small difference, but Titan is also a lot colder than the Moon. That means that the gas molecules in its atmosphere move more slowly, and therefore that fewer reach escape velocity.

Using the formulas in GURPS Space, Titan's black-body temperature is 90 K and its minimum molecular weight retained works out to 26.9 a.m.u. Whereas the Moon's black-body temperature is 278 and its minimum molecular weight retained works out to 102.5 a.m.u. The molecular weight of nitrogen gas is 28 a.m.u. So that's why Titan has retained nitrogen whereas nitrogen would escape fairly quickly from the Moon.

[Anthony]

Originally Posted by Agemegos

So that's why Titan has retained nitrogen whereas nitrogen would escape fairly quickly from the Moon.

Note that "fairly quickly" means "quickly on a geological time frame"; 2.38km/s is still pretty far down the velocity distribution tail for atmospheric gases. Estimates I find online are that it you could get an atmosphere that lasted a thousand years or thereabouts.

[scc]

Originally Posted by Fred Brackin

It's obvious that nitrogen is desirable as an atmospheric dilutant anywhere they don't have it but what does isolating it on Venus and then getting rid of it have to do with the atmosphere of Venus? That's 95% carbon dioxide.

I've seen proposals that capture the carbon and turn it into many many miles tall cooling towers of diamonoid (pumping heat from the lower atmosphere to the upper where it is more easily gotten rid of).

You're probably going to need the nitrogen on Venus to make bio-mass when it cools enough.

By contrast the moons of Neptune are very unlikely to e terraformed and you can mine the solid nitrogen with cryogenic nanites or aomething like that.

Because the nitrogen in Venus' atmosphere alone gives it an atmospheric pressure 3 times that of Earth's, so if I want an Earth normal atmosphere on Venus, a lot of that has to go.

As for cooling Venus, I'm taking the sunshade approach, once it's complete it seems like it'll take 70 years for the CO2 in it's atmosphere to liquefy.

You might be right about the bio-mass bit but.

Originally Posted by Anthony

The simplest option for Mars is to head out to the Kuiper belt or Oort cloud (depending how patient you are; further out = less delta-V but more time) and start kicking comets towards Mars. Mostly what this will get you is water, but you need a thousand times more water than you need nitrogen, so the ammonia content of the comets should do the job.

Scooping up the atmosphere of Venus won't do you any real good, because it's not made up of the things you need anyway; it's mostly carbon dioxide, which isn't what Mars needs. Venus is a ridiculous mega-engineering project, far beyond the scope of Mars, but if you're really dedicated to doing it you want to deliver large amounts of water, re-spin the planet, restart tectonics so you can bury a lot of the CO2, and give the entire planet a sun shade. You might be able to start in on that by whacking it with a substantial planetoid, assuming you don't mind waiting a million years for it to be habitable.

The CO2 is actually useful because the carbon will be needed for creating biomass and the excess water can be combined with hydrogen imported from Saturn to make water. I expect that this plan will involve starting soil conditioning really early.

Originally Posted by Agemegos

Titan is 48% larger than the Moon. On the other hand it is less dense. Taking one thing with another, Titan's escape velocity is 2.64 km/s, whereas the Moon's is only 2.38 km/s. That's a small difference, but Titan is also a lot colder than the Moon. That means that the gas molecules in its atmosphere move more slowly, and therefore that fewer reach escape velocity.

Using the formulas in GURPS Space, Titan's black-body temperature is 90 K and its minimum molecular weight retained works out to 26.9 a.m.u. Whereas the Moon's black-body temperature is 278 and its minimum molecular weight retained works out to 102.5 a.m.u. The molecular weight of nitrogen gas is 28 a.m.u. So that's why Titan has retained nitrogen whereas nitrogen would escape fairly quickly from the Moon.

The Moon lacks an atmosphere more because it formed so late in the development of the Solar System then anything else.

[Agemegos]

If the Moon had formed with a thick atmosphere it would have lost it to Jeans escape long before now, and if it were provided with a nitrogen-oxygen atmosphere that atmosphere would evaporate to space in a millennium or so. The example of Titan doesn’t indicate that the Moon would be able to retain a thick nitrogen atmosphere, because the Moon is much hotter than Titan.

[scc]

Originally Posted by mlangsdorf

Okay, what was your original, gaming related question? You seem to have this all worked out to your satisfaction.

I want to know if people think it would make for a good game, I'm not sure it last beyond one or two sessions, but it's repeatable and there are other places to go in the system and do the usual Traveler inspired tramp freighter things

Originally Posted by johndallman

How are you planning to lift all that mass to Venus orbit? You'd have to speed up Venus' rotation a lot to let you use orbital elevators.

Originally Posted by scc

Um, no rockets, either a mass driver to increase rotational speed to reactionless drives tailored to produce space fighters (They have a top speed).

Originally Posted by Varyon

How are you seeing this marathon work? Are we talking a race to see who goes from Venus to the Moon fastest with everyone starting in Venus' orbit? A staggered race where you just track how long it takes each vessel for a single trip? A variant of one of the previous where how much mass of nitrogen the vessel is transporting is factored in? A "race" where victory goes to the vessel that transports the most nitrogen to the Moon during the "nitrogen transport" phase of the terraforming project? Something else? And do you see the Mars project involving a separate race, or would it be something like the above where transporting to Mars instead of the Moon is worth more points?

Yes an actual race, the races by clipper ships to bring tea to England was on my mind when I came up with this. The event is annual and the first across the line wins. Vessels get around by Mag-Sail assisted by particle accelerator stations so there's something of a starting whistle when that fires up but starting early is allowed (Because it doesn't automatically give you an advantage). At this point I'm not sure then carting stuff to Mars would begin, it could start at the same time or later on, I'm not sure.

Originally Posted by whswhs

The pressure part makes sense. Atmospheric pressure is the weight of atmospheric gases, which is the mass of those gases times the acceleration of gravity. The moon has 1/6 g, so if you have six times as much atmosphere, you'll have the same pressure. (The scale height is inversely proportional to gravitational acceleration, so it will be six times as great.)

But with the lower gravity the atmosphere will escape far faster.

I calculated how much would be needed based upon Titan's atmospheric pressure.

[Anthony]

Originally Posted by scc

I want to know if people think it would make for a good game

Running bulk freighters is not in general going to be an interesting game, though it can be the backdrop for something more exciting.

[Fred Brackin]

Originally Posted by scc

I want to know if people think it would make for a good game, I'm not sure it last beyond one or two sessions, but it's repeatable and there are other places to go in the system and do the usual Traveler inspired tramp freighter things

.

I'm having trouble seeing a place for mag-sails and any reactionless drive usable for heavy lifting in gravity wells like that of Venus. Even oif the reationless drive has a speed limit like 8 miles per second (relative to what?) drifting at that speed for free compared to the trouble and expense of mag-sailing looks pretty attractive.

It's also one of those "Space" things where you ask "Why are there humans involved in this?".

Races are also pretty hard to make into actually interactive rpg stuff. It was one of SJ's genius moments when he decided in Car Wars to sideline the going in circles and just have the cars shoot at each other.

It's also a problem that a solar system government big enough to be funding (and presumably supervising) this sort of terraforming will be squashing any Player Character shennaigans.

Of course,a society wealthy enough to be able to afford this sort of thing usually does not have that much use for terraformed planets.