Chemistry question

[Lowly Uhlan]

My computer is not cooperating...

 

I am designing a hard SF Star hero campaign. Taking place mostly on the outer worlds of our Solar system. After scouring the web, I've found that several of the planets and their moons have organic compounds mixed with frozen methane, water ice,frozen hydrogen,ect..My chemistry knowledge is weak and I had a few questions for the collective minds on these boards:

 

1)Aside from these organic compounds being useful for production of plastics and petrochemicals, how useful would they be as the "basic stock" for food or hydroponic food production?

 

2)What process would be used to seperate the compounds from the water,hydrogen,methane,ect.?

 

3)How volitale is frozen methane? How much heat would be neede to ignite it say on the surface of Charon (very, very cold)?

 

While I'm going for the "hard" SF approach, I'm definetely open to using "speculative" technology, nothing as advanced as replicators though.Trade with the inner planets is not an option, the game takes place after a devestating war. Everyone is fighting over the scraps of a defunct confederation. Even if one of the above questions can be answered, I would be greatful.

[noumena]

Re: Chemistry question

 

I'm not a chemist, so:

1. I don't know.

2. Distillation, I think. These compounds have different melting and boiling points.

3. (Numbers from the Web, confirm independently if accuracy is important to you.) Charon is at about 40 K, and methane melts at around 90 K and boils around 110 K. I can't seem to find the specific heat of liquid methane, so I'm not sure how useful those numbers are to you. The specific heat of gaseous methane, however, is approximately equal to twice that of air, roughly the same as steam. The upshot is that a given one-off heat source (laser, explosion, etc) will only affect gaseous methane about half as much as it will air.

 

Granted, you're most interested in the outer planets, but this link has some info on Mars colonization. The papers on In-Situ Resource Utilization might be useful to you.

http://www.nw.net/mars/

 

For flavor, consider reading Joe Haldeman's book The Forever War. The opening section has the recruits training in their battlearmor on the surface of Pluto. One of their big concerns is learning to fall so that they land on their stomach. The heat radiator on the back of their suit will sublimate the surface of Pluto and cause an explosion, killing the recruit. (It's also a good book to read in any event.)

 

Making food is going to be pretty hard for people in the outer planets (or in space, period). The amount of energy it takes to equal sunlight is pretty amazing, so growing plants purely by hydroponic means is probably going to be prohibitively difficult. Since you're indulging in speculative science here, how about genetically modified mushrooms that grow on decomposed organic compounds harvested on the outer planets? It also allows pirates to try to intercept food shipments from the few Martian survivors to the dominant outer-planet faction, since freeze-dried broccoli is a luxury worth more than its weight in gold.

 

Hope this helps.

-noumena

[Balok]

If you want to take an approach that's closer to what will probably happen, consider the use of genetically engineered creatures. Starting with bacteria (some of which can survive astonishingly low termperatures) and moving up to larger forms.

 

Such creatures could take these organic compounds and produce food from them. They would use part of the material to energize their own metabolism.

 

For example, a form of bacteria could turn hydrocarbons (including methane) and water into simple and complex carbohydrates.

 

Proteins would be harder, requiring more specialized forms.

 

Such food is likely to be an unappetizing but nutritious paste when first introduced, making spices a trade commodity. As the tech gets more advanced, flavors and texture could be added by new organisms.

 

Heavier atoms (like calcium and metals) would also be trade goods; these could be added as supplements or mixed into the food vats to be incorporated by the specialized organisms. Many of them are necessary for good health. For an idea of which, check out a site like http://www.webmd.com, or consult the side of a bottle of multi-vitamins (like Centrum).

[Lowly Uhlan]

Thank you Sirs!

Liked the idea of the engineered mushrooms.Actually the Martians will be the dominant survivors, the player characters will end up in conflict with them. Beside the point though.

 

Even thogh I new the Sun's light is diminished way out there I hadn't figured that in. Genetic engineering will be a good solution to the food production problem.Good call on the bacteria.

 

Anyone else care to enlighten me?

[cypar7]

2) What process would be used to separate the compounds from the water, hydrogen, and methane, ect.?

 

Fractional Distillation. Distillation in which rectification is used to obtain product as nearly pure as possible. A part of the vapor is condensed and the resulting liquid contacted with more vapors, usually in a column with plates and packing. Also a distillation in which the product is collected in a series of separate components of similar boiling range. Problems can occur when trying to separate the alcohols from water, but if you can get to outer planets I am sure the distillation process would have advanced.

 

This process should separate the organic componets well. The inorganic material remaining could be used as mirconutriants in question one.

 

3) How volatile is frozen methane? How much heat would be needed to ignite it say on the surface of Charon (very, very cold)?

 

Frozen methane is not volatile, but need clarification on the specific information requested.

[DigitalGolem]

You might want to check out gurps: TransHuman Space and its outer-system supplement Deep Beyond. Both have lots of info on resources to be found in the outer system, and how to exploit them. Fine source material, just waiting to be converted to the Hero System.

 

Almost forgot! Under Pressure is the latest THS release, and it's got info on the oceans of Europa and Titan.

 

DGv3.0

[noumena]

Regarding the volatility of methane, rember that you need an oxidizer to get it to ignite anyway. Once the reaction starts going, it's exothermic, so it should keep going until you run out of fuel or oxidizer. That having been said, I don't think Charon has pools of oxygen lying around, so igniting the methane probably isn't going to be an issue normally.

 

Regarding diminished sunlight: Sunlight is going to be so diminished in the outer planets that using genetic engineering to enable photosynthesis sort of strains plausability in a hard science setting. I think you'll probably want to go with my genetically engineered mushrooms or Balok's nutritious paste-forming microbes. His microbes are probably far more plausible in the near term. However, I do think you'd probably want to keep these microbes in a vat rather than just set them loose on a moon somewhere. Not out of ecological considerations, but simply for ease of gathering.

 

Your Martian remnants are going to have a serious advantage over the rest of the solar system in their ability to grow and export crops. Seriously. Mars gets enough sunlight for photosynthesis, its atmosphere is thick enough to block out the requisite amount of solar radiation, and (with fertilizer) the soil could probably support agriculture. Growing crops on the moon isn't really a good idea - you'd get enough sunlight, but you'd need too much radiation shielding to prevent solar flares from killing your plants.

 

As for exporting, remember that Mars' gravity well is much weaker than Earth's. It's going to be a lot easier to get high-bulk low-density things (like most foodstuffs) off Mars. I don't know what kind of propulsion scheme you're planning on right now, but remember that one of the most expensive parts of current space exploration is simply getting to orbit.

 

I still like the idea of Neptunian pirates raiding Mars for brussel sprouts. I imagine after a lifetime of eating tasteless paste, piracy for vegetables might become seriously attractive, and it has this nice combination of Buck Rodgers pulpishness and hard science plausibility.

 

-noumena

[Lowly Uhlan]

A lot to consider. When I asked what about the volatility of frozen methane I guess I was wondering about what would happen if a really hot surface came in contact with the frozen gas. Its been a really long time since I've read The Forever War . And yeah, the martians will have a definite edge-in everything. It wouldn't be a proper roleplaying campaign without the odds not being in favor of the player characters:D

[Farkling]

The Martians need a Space Elevator/Tether system. That will cut thier surface to space access even more. Mount gun cars on the elevator at either end to fight off pirates. I think it is within scientific reason to attach a tether to Phobos or Diemos, though you might need to alter the internal composition of the moon slightly for the correct mass on that anchor.

 

Other real science effects:

Bussard ramjets are not efficient within the solar system. Neither are most constant rockets. Delta Vee (velocity changes) are priceless commodities. If you are not pushing into Fusion technology or better, then solar sails will be pound for pound a most efficient long haul accelerator. Assitance from a large scale pumped lasers on Luna, or large stabilized asteroid in the belt, and even on an airless moon of Jupiter/Saturn would increase sail effieiency. (Could some madman turn those into wepaons?) Computers would co-ordinate the impact and flight paths of freighters requiring boosts.

Also, magnetic accelerators would predate lasers/solar sails in the evolution of solar travel. The magnetic cannon is used to accelerate the object, and fuel sufficient for steering is included on board to hit the cannon and decelerate objects on the other end. This conserves energy too, as the braking effect in the accelerator could possibly be designed to return power to the accumulators by magnetizing the ship temporarily, or simply by proper accelerator design. Note that acceleration resistant goods (ore, organic pastes, indestructible alien artifacts, durable parts) can be shipped MUCH faster than liners using this system, as they can be accelerated by the cannons to a higher speed. The military also likes these as they are easier to convert to weapons thatn the solar sail lasers...

 

Hydroponics can be engineered to grow from whatever source of organic material you have available, and seeds. Light can actually be generated by solar mirrors, though out Pluto way it will take a large array. Solar mirrors can provide heat for distillaion also, and an orbital solar furnace in production can melt virtually anything. Theoretically, a large solar furnace could be used to heat an entire ASTEROID up to the point where you could fractionally distill it...but STRICT temperature controls are needed.

[keithcurtis]

First off, good luck on your campaign. This sounds virtually identical to the set-up I used for my Solar Colonies campaign, which was the most satisfying GMing experience I have ever had.

 

The Solar Colonies were a pre-FTL solar system wherein Earth had been lost to war and disease. I struggled with virtually all of the problems you have enunciated.

 

For food. Mars was the solar system's Ag belt. Mariner Valley was basically a long canyon farm. (I originally chose it thinking the air pressure of a terraformed Mars would be slightly higher there and only long afterward learned that Mars "bulges" at that point and there are far lower elevations on the planet. Oh well.)

 

Mars and Luna were the main powers in the Colonies. Mars was fresh, young, vibrant and had easily exploitable resources. Luna was far better established and had a lot of the equivalent of "old money".

 

I did a lot of web scouring looking for natural resources and eventually decided that my players didn't really care so long as it sounded reasonable. I would just use phrases like, "rare elements" and leave it at that. Occasionally, if the point was important, I would use the data I had collected though.

 

Food. I had a product called "Synth" which was pretty much exactly what Balok described: Vats of bacteria breaking down natural raw materials and waste into a dull paste that could be flavored and textured in a variety of ways. Originally Synth was a ruthlessly exploited monopoly of one colony (Titan) and nearly started another war, but the secret was broken and other planets (and moons) became more self-sufficient. IIRC, I had a fishery on Europa and a prison/refinery on Io.

 

Transportation. Here I bowed to story demands and used a Niven-esque fusion drive. This requires some hand-waving, since the conversion rates for fuel to velocity are nigh magical. However, I figured if it's good enough for Larry...

 

I used a spreadsheet that plotted the planets' positions, figured your mass and fuel and engine efficiency and then gave you travel time based on days/weeks of acceleration, turnaround and decelleration. I had to use algebra and trig since my brain can't do calculus, but it was close enough for a game. Most travel times were on the order of weeks or months.

 

Please feel free to click opn the Solar Colonies link in my sig to look for anything useable. It's an old site, but it has a timeline, some governmental organization and colony writeups.

 

Keith "Heh. My players learned to hate Mars, too" Curtis

[Lowly Uhlan]

More good ideas.Thanks all.

 

I'll post on the progress of the game as it develops. Have to take a break to run a couple sessions of the CODA-Trek game I'm plaing in to give the GM a chance to play.From Hard SF to completely rubber SF-oh well...

 

BTW ,Keith that Solar Colonies game sounds cool.Have you posted any of your background stuff on these boards?

[Guest Celt]

Light for photosynthesis is relatively simple to produce using electricity. When you've got a fusion plant you likely have power to burn.

 

Hydroponics with normal plant growth has the benefit of providing CO2/O2 exchange by natural means and can provide sustenance. This wouldn't be something that is available except on the largest spacecraft, if even then. Maintenance would likely be extensive and time-consuming depending on your level of automation.

[keithcurtis]

Originally posted by Lowly Uhlan

BTW ,Keith that Solar Colonies game sounds cool.Have you posted any of your background stuff on these boards?

Thanks!

I've posted the write-up for the T'Katran race on a couple of "Gimme some alien ideas" threads, but most of the campaign lies in note form. It wasn't until I started the "Savage Earth" that I really attempted to fully document a campaign. The stuff on the SC site was mostly background stuff the players could reference.

 

Keith "I did build a 3d spaceship model to Hero scale for the campaign" Curtis

[McCoy]

Originally posted by Farkling

The Martians need a Space Elevator/Tether system. That will cut thier surface to space access even more. Mount gun cars on the elevator at either end to fight off pirates. I think it is within scientific reason to attach a tether to Phobos or Diemos, though you might need to alter the internal composition of the moon slightly for the correct mass on that anchor.

Um, no. Both Diemos and Phobos are too close to the surface as they are now. They would have to be moved out to Clark orbit before an orbital tether coull be built. If the Martians (or should that be Marsmen?) have the power to move ten mile asteroids around, then yes, using them as the anchor would kill two birds with two very large stones.

[Farkling]

I was thinking about theoretically changing the density of an existing moon of mars and finding a "safe" way to anchor it.

 

I read a reprint sci-fi novel on elevators recenty...the concept seems "just close enough" for game physics. I just don't know if the moon would need to be heavier or lighter...I cannot remmeber the name of the book. It involved a mechanical spider weaving a high test cable array, and asteroids. There is a really good section on the concepts for "planoforming" asteroids also. Heating, spinning, restructuring...

 

If the moons need to be denser (ie, mass added), it might be more practical to MOVE an appropriate asteroid into Clark orbit

 

Stellar Mechanics and gaming::

A) Read "Clarke County Space" if you can find a copy at the used book store. Alan Steele writer. The space colony/habitat physics are pretty good in that.

Theoretically, if there were a usable engine/source, asteroids could be relocated from the belt, or a comet captured. Even an engine that burned the material ON the rock would be appropriate, as would a "tranport engine" crew to mine reaction mass and care for the engine. Only a small steady thrust is absolutely necessary.

C) The martians could have had their attention called to near space upon the initial colonization attempts. Fits in with the moving of asteroids/icesteroids. Fresh water would be desperately needed for us to colonize Mars, so we fetch it from the asteroid belt. Perhaps the first one got dropped and the tectonic upheavel brings Mars into the stellar picture with "Who threw this trash in our yard?"

Large scale fusion reactors negate the need for water at best, as there is enough power to MANUFACTURE water from the Oxygen and Hydrogen cracked from compounds mined on Mars or Luna, or various other moons. At worst, the fusion reactors greatly accelerate asteroid transport ability, and make small water and hydroponics demands elementary.

[McCoy]

Originally posted by Farkling

I was thinking about theoretically changing the density of an existing moon of mars and finding a "safe" way to anchor it.

 

I read a reprint sci-fi novel on elevators recenty...the concept seems "just close enough" for game physics. I just don't know if the moon would need to be heavier or lighter...I cannot remmeber the name of the book. It involved a mechanical spider weaving a high test cable array, and asteroids. There is a really good section on the concepts for "planoforming" asteroids also. Heating, spinning, restructuring...

 

If the moons need to be denser (ie, mass added), it might be more practical to MOVE an appropriate asteroid into Clark orbit

 

Stellar Mechanics and gaming::

A) Read "Clarke County Space" if you can find a copy at the used book store. Alan Steele writer. The space colony/habitat physics are pretty good in that.

Theoretically, if there were a usable engine/source, asteroids could be relocated from the belt, or a comet captured. Even an engine that burned the material ON the rock would be appropriate, as would a "tranport engine" crew to mine reaction mass and care for the engine. Only a small steady thrust is absolutely necessary.

C) The martians could have had their attention called to near space upon the initial colonization attempts. Fits in with the moving of asteroids/icesteroids. Fresh water would be desperately needed for us to colonize Mars, so we fetch it from the asteroid belt. Perhaps the first one got dropped and the tectonic upheavel brings Mars into the stellar picture with "Who threw this trash in our yard?"

Large scale fusion reactors negate the need for water at best, as there is enough power to MANUFACTURE water from the Oxygen and Hydrogen cracked from compounds mined on Mars or Luna, or various other moons. At worst, the fusion reactors greatly accelerate asteroid transport ability, and make small water and hydroponics demands elementary.

Think the mass of Phobos, or even Deimos, would be more than sufficent, and IIRC they are both nickle-iron bodies, probably no ice and very little silica, that would be good.

 

What I forgot ie that they are in retrograde orbit! Not only are they too close to the planet, they're moving in the wrong direction!

 

Definitely more practical, in terms of delta V, to go out to the belt and move another asteroid into place. But then how do you keep them from runing into the elevator after it's built?

[Farkling]

Ooops. Retrograde orbit. That's what I get for being a science fiction reader instead of an actual astronomer. I certainly can't see Niven, Bear, or Steele making such a mistake, and Bujold stories seldom touch on real physics.

 

If near psuedoscience allows for us to insert an asteroid into an appropriate orbit, then we have three possible solutions::

 

1) We pick an asteroid we can place BELOW the P & D orbits, so collision won't happen until further degradation of the PnD orbits. This could cause either unwanted tidal effects (on the crust, after all, there is no ocean), or it may not be HIGH enough for a functioning elevator.

 

2) We put our elevator anchor beyond those orbits. We now need to outfit PnD with some form of steerage, OR we ned sufficient construction technology to "bend" the elevator. Though that may not be necessary, as the elevator would be an extremely small target in their orbits. We may just need attitude adjusters/jets to cope with stresses from the lunar bodies. Or the martians crunched up the moons to build the elevator, making the question moot...easier than hauling the materials OUT of the gravity well.

 

3) This idea is scrapped, and a magnetic accelerator cannon with a gigantic capacitor system is built beneath the Mars surface, after all, the martians have been there a very long time. The accelerator is underground and gradually curves, like a roller coaster, dipping down and then curving upwards (after miles?) to exit through Olympus Mons. Actually, the diameter of Olympus Mons might be sufficient enough to spiral the accelerator up the crater itself. We could then assume that the Martians camoflauged it against casual recognition from space or ariel flyovers. Depends on the size of the accelerator. Olympus Mons is a huge target to home in on, and once in range pilots can adjust trajectory to hit the intake of the accelerator for landing.

 

The accelerator also makes a fantastically powerful difficult to aim weapon if they have enough ferrous material available. They could throw it at planets, moons, asteroids...

[keithcurtis]

If I could recommend Kim Stanley Robinson's Red Mars / Green Mars / Blue Mars trilogy, he has put extensive thought (and exhaustive scientific detail) into these very questions. The books are a little dense at times, but if you really want some plausible-sounding solutions, I think everything you need is there.

 

Keith "Probably wouldn't read them twice, though" Curtis

[Dr. Anomaly]

A "ballast" asteroid would have to be in a considerably higher orbit than Phobos. For one thing, that moon orbits fairly rapidly...you need your anchor point to be far enough out that it's almost, but not quite, in a geosynchronous (areosynchronous?) orbit. The bit of discrepancy provides for tension to keep the tether (elevator cable) taught, but too much will snap the cable; not enough and the cable will go slack -- neither of which are desirable.

 

Phobos completes an orbit in about 8 hours, far too low and fast; Deimos completes an orbit in about 30 hours, too high and slow. You need something in between, and some way to make sure Phobos doesn't come whipping along and slice your anchor cable in two.

[McCoy]

Originally posted by Dr. Anomaly

Phobos completes an orbit in about 8 hours, far too low and fast; Deimos completes an orbit in about 30 hours, too high and slow.

And both of them in the wrong direction, against planetary rotation. Mars' rotation period is 24h 37m 22.65s, the center of mass of the elevator needs to be in an orbit with the same peroid, anyone remember how to calculate that?

 

Orbital period of Deimos is just under 30 1/2 hours, if it were going in the right direction amd a means for moving asteroids was available, reasonable delta V could nudge it into Clark orbit.

 

But turning a retrograde orbit into a prograde one? Only thing that comes to mind is to "nudge" it into a more inclined orbit, going through a polar orbit, then back into an equatorial orbit. Could be done with enough delta V, and enough time. I'd want a couple thousand years for that one.

[Farkling]

So, general consensus is that we need to collect an asteroid.

While we are at it, we will melt down Phobos and use it for raw material, or we can try blasting it into a higher orbit.

 

Now the Space Elevator can be built.

 

Pity. I was growing attached to the martians having a concealed magnetic accelerator cannon.

 

"If you inconsiderate humans drop one more icesteroid on our planet, we are going to start shooting back"

[Dr. Anomaly]

Originally posted by McCoy

And both of them in the wrong direction, against planetary rotation. Mars' rotation period is 24h 37m 22.65s, the center of mass of the elevator needs to be in an orbit with the same peroid, anyone remember how to calculate that?

 

Orbital period of Deimos is just under 30 1/2 hours, if it were going in the right direction amd a means for moving asteroids was available, reasonable delta V could nudge it into Clark orbit.

 

But turning a retrograde orbit into a prograde one? Only thing that comes to mind is to "nudge" it into a more inclined orbit, going through a polar orbit, then back into an equatorial orbit. Could be done with enough delta V, and enough time. I'd want a couple thousand years for that one.

The retrograde thing had already been mentioned, so I didn't think tossing it in again would be necessary. Ah, well, perhaps I should have...it's only a few extra electrons, right?

 

A 'Clark orbit' actually needs to be a little lower than one necessary to exactly equal the planet's rotation...that way, when the ballast mass is traveling at a speed to keep it synchronized over the same spot on the surface, it will keep the tether under tension because it (the ballast mass) is trying to escape into a higher orbit. (Remember: higher orbit, higher speed, but more time to go around the planet.) The really tricky part is getting the speed right to keep the cable under enough tension to make it usable but not enough to snap it.

 

I don't remember off hand how to figure it; I'd have to dig through a few books, and I don't have the time just this instant...sorry.

[keithcurtis]

Originally posted by Dr. Anomaly

-snip-

You need something in between, and some way to make sure Phobos doesn't come whipping along and slice your anchor cable in two.

 

KSR solved this problem by putting a vibration in the cable. The period of vibration was such that everytime Phobos came along, the cable at that point was just a little to the south or north.

 

Keith "Music of the Sphere's, anyone?" Curtis

 

PS. I believe the cable was a fullerene material.

 

PPS. I would NOT want a space elevator on my planet. Can you imagine the effect of terrorists?

[McCoy]

Originally posted by Dr. Anomaly

The retrograde thing had already been mentioned, so I didn't think tossing it in again would be necessary. Ah, well, perhaps I should have...it's only a few extra electrons, right?

 

A 'Clark orbit' actually needs to be a little lower than one necessary to exactly equal the planet's rotation...that way, when the ballast mass is traveling at a speed to keep it synchronized over the same spot on the surface, it will keep the tether under tension because it (the ballast mass) is trying to escape into a higher orbit. (Remember: higher orbit, higher speed, but more time to go around the planet.) The really tricky part is getting the speed right to keep the cable under enough tension to make it usable but not enough to snap it.

 

I don't remember off hand how to figure it; I'd have to dig through a few books, and I don't have the time just this instant...sorry.

No.

 

The center of mass of the elevator needs to be standing still relative to the ground, geosyncronous orbit, or Clarke orbit (after Sir Arthur C Clarke, who was the first to point out that a geosyncronous orbit would be a useful place to put a communications sattelite).

 

From that center of mass you build up and down at the same time. The length from Clarke orbit to the ground is fixed, the upper limb can be longer or shorter, as long as it has the same mass.

 

Rather than acored to the ground and being under tension, the entire length of the elevator is in orbit.

[Fuzzy Gnome]

Prior to this thread, I never heard of Mars's moons being retrograde. Does anybody have any sources that say they are?