What If?

[sgbrown]

Originally posted by atpollard:
</font><blockquote>quote:</font><hr />Originally posted by SGB - Steve B:
I'd love to see one on colonization of a hostile world such as Venus {as we know it- vs the pulp fiction type}.

That article was better than 90% of the fiction worlds that I have read about.
Do you think a floating city could work on a gas giant? </font>[/QUOTE]The article makes an excellent case for it working on Venus. Don't see why it wouldn't work on a Gas Giant in the habitable zone - provided breathable air is less dense than the gas giant atmosphere (not likely - but possible.)

Quick Summary of the Article: At about 50 km, Venus atmosphere is near earth normal gravity and temperature at 1 atm of pressure. There's sufficient atmosphere above to provide shielding from cosmic rays and the solar flares. And breathable atmosphere is lighter than Vensus atmosphere - so it can provide the lift.

Other that the technology for getting the resources there, we've had pretty much what we need since the mid to late 30's (Consider the Hindenburg with breathable air instead of Hydrogen for lift.) Issues to still work out include closed ecosystems/recycling, sufficient light wieght protection from the sulphric acid in the atmosphere - and a reason for being there.

That's why I think this would make an exceptional Sci Fi setting - exotic as all get out, but with valid hard science solutions.

Steve B

 

[atpollard]

Originally posted by Space Cadet:
In a hostile Venus, either your environmental suit keeps you alive or it does not.

If it does not, you suffer a quick death, not much of an adventure.

If it does, you get to walk around in a rather boring landscape collecting rocks.

Given your personal preferences, re-read the article and imagine Captain Nemo meets Space 1889, except without the magic. Imagine a Venus colony founded by Van Braun in the 1970's (Apollo Era Tech), isolated by WW3 in the 1980's and forced to evolve and survive on their own until the Southeast Asian Space Agency makes contact in 2080.

Read up on ocean volcanic life and translate it to Venus atmosphere as alien life forms.

No adventure seeds to be found there.

 

[Space Cadet]

Interesting article. Of course 50 km above the Earth's surface is nearly in space, above Venus its 1 bar. 50 degrees celsius is a bit toasty, probably radiator fins can disappate some of that heat, cooling the oxygen and nitrogen does make it less bouyant though. Living in Aerostat communities is a bit like the Jetsons, you'd need flying cars or airplanes to commute from one areostat to the other. areo stats would probably move in realtion to each other, so each one would have to be tracked by satellite. While a balloon would be great for living, for transportation, a heavier than air airplane would be desirable, Airbreathing jet engines wouldn't work, a flimsy solar powered airplane could work, although its speed would not be great, it would have a large wing structure to hold solar arrays, and it would need a large wing span in anycase to maximise lift due to its slow relative airspeed. Rocket planes are of course possible.

One interesting way to "move" would be to anchor the airplane to the ground and let the relative superrotation of the atmosphere provide the lift while the airplane remains stationary relative to the Surface of Venus. Venus's atmosphere would then bring the "destination" aerostat around towards the air plane as it waited. Some northward or southward traverse may be necessary for intercept.

It would be interesting to postulate a parallel Venus of sorts though, say a "Bermuda triangle" exists in Venus's atmosphere leading to a more habitable parallel Venus. Hostile Venus would be more humans vs humans, or perhaps humans versus robots.

Back to your topic, an aerostat community would have a major problem on its hands. Dropping into Venus's atmosphere from space is alot easier than getting back out into space from Venus's atmosphere. I think in the early term, people sent to Venus would be stuck there as there would initially not be enough of them to maintain the infrastructure to launch a spaceship back into orbit. One possibility is a penal colony Criminals would be exiled to Venus, provided with the means to stay alive, grow their own food, and resupply is a possibility, but getting back to orbit requires multi-staged chemical rockets, or some kind of reusable 2-stage shuttle for example.

Lets say there is a two-stage shuttle that gets passengers into Earth orbit, a nuclear powered system ship that gets passengers from Earth orbit to Venus orbit, and a reentry capsule that was lifted up to the system ship by the Earth shuttle and delivered to Venus by that System ship, and then dropped into Venus's atmosphere.

The Two-stage Shuttle on Earth consists of a lower Rocket Plane Stage that takes off from runways and lifts the upper stage high in the atmosphere and releases it, where it completes the journey to Orbit. A similar thing would work on Venus too of course, the only difference being is that their would not be enough people or infrastructure to maintain the lower stage rocket plane and turn it around for reuse when the Venus shuttle return's to Venus's atmosphere. Labor is scarce on Venus, on Earth the Two-Stage shuttle requires an army of technitians to maintain the shuttle, and the lower stage, no similar repair facility exists on Venus. You might be able to send the Upper stage back to Earth for a refit, or repair it in orbit, but the lower stage rocket plane would have to remain within Venus's atmosphere.

On second thought criminals are probably not sent to Venus, not until travel off Earth becomes much cheaper at any rate, travel off Venus would then become proportionally more feasible too.

A Space elevator would work on Earth, and it would Work on Venus too, its just that the lower end would dangle rather than being anchored to the surface.

But since we're talking fiction anyway, exploring Venus as it might have been is also fun as exploring it as it is.

 

[sgbrown]

Originally posted by Space Cadet:
...clip...
Back to your topic, an aerostat community would have a major problem on its hands. Dropping into Venus's atmosphere from space is alot easier than getting back out into space from Venus's atmosphere. I think in the early term, people sent to Venus would be stuck there as there would initially not be enough of them to maintain the infrastructure to launch a spaceship back into orbit. One possibility is a penal colony Criminals would be exiled to Venus, provided with the means to stay alive, grow their own food, and resupply is a possibility, but getting back to orbit requires multi-staged chemical rockets, or some kind of reusable 2-stage shuttle for example.

...clip...

Given a the postulated m-drive (meaning a drive to allowing you to reach space and manuever in space without carrying the disposable reaction mass), which in Traveller shows up at TL 9, the access issues go away. Of course you're still left with why?

 

[Space Cadet]

With the current Venus, why is a good question. With the Pulp Venus, those M-Drives are made by the aliens and no one can explain them.

 

[sgbrown]

In the pulp version you've also got usable land, people and other reasons to be at Vensus.

Real world, lots of adventure if theres a colony or colonies there - but why would we put them there?

ATP's question about wether or not a similar concept would work with a Gas Giant is interesting since in a traveller scenario a colony around and in a gas giant makes a lot of sense.

SGB

 

[Malenfant]

Originally posted by SGB - Steve B:
ATP's question about wether or not a similar concept would work with a Gas Giant is interesting since in a traveller scenario a colony around and in a gas giant makes a lot of sense.[/QB]

I'd be curious to know why you think a gas giant colony would make a lot of sense. As an environment it's at least as hostile as a corrosive hellhole - the atmosphere is full of hydrogen that seeps into everything, and if the grav plates holding up the colony fail then everyone plummets to their doom. Also you've got pretty major radiation levels, ridiculously strong winds (usually hurricane-force minimum if a storm comes through) and extreme weather that makes the worst of what we have on Earth look like a light breeze. Plus the generally high gravity makes it more of a pain for ships to enter and leave.

 

[atpollard]

Originally posted by Malenfant:
I'd be curious to know why you think a gas giant colony would make a lot of sense. As an environment it's at least as hostile as a corrosive hellhole - the atmosphere is full of hydrogen that seeps into everything, and if the grav plates holding up the colony fail then everyone plummets to their doom. Also you've got pretty major radiation levels, ridiculously strong winds (usually hurricane-force minimum if a storm comes through) and extreme weather that makes the worst of what we have on Earth look like a light breeze. Plus the generally high gravity makes it more of a pain for ships to enter and leave.

Looks like somebody didn't read the article.

http://powerweb.grc.nasa.gov/pvsee/publications/venus/VenusColony_STAIF03.pdf

It might not be possible on a Gas Giant, but many of those issues were covered in the article.

 

[Jeff M. Hopper]

Originally posted by atpollard:
Looks like somebody didn't read the article.

He was too busy trying to oppress us with his realism.

 

[Malenfant]

Originally posted by atpollard:
http://powerweb.grc.nasa.gov/pvsee/publications/venus/VenusColony_STAIF03.pdf

It might not be possible on a Gas Giant, but many of those issues were covered in the article. [/QB]

Well for starters, breathable air wouldn't be a lifting gas on a jovian, since everything else is denser than the ambient hydrogen. I think the only thing buoyant there would be hot hydrogen, and I'm not sure it'd have much lifting power. And obviously you're not going to put a town in a hot hydrogen envelope.

Also, Solar power would only be abundant as a power source on jovians in the inner solar system, CO2 and Nitrogen aren't particularly abundant in most gas giants, silicon and other metals would have to be imported from satellites around the gas giant (which may all be ice covered)...

So no, most of the issues specific to living in a jovian's atmosphere aren't covered at all by that article (it doesn't even mention many of the problems I talked about, so I'm not sure why you pointed me to the article again).

Sorry if that's "oppressing you with realism".

 

[atpollard]

Originally posted by Malenfant:
So no, most of the issues specific to living in a jovian's atmosphere aren't covered at all by that article (it doesn't even mention many of the problems I talked about, so I'm not sure why you pointed me to the article again).

Mal, please do not take offense at this, it is intended as an answer to your question and nothing more.

The basic premise of the article was that although Venus at first appears to be a very bad place to live, it could have a number of advantages. A floating balloon of breathable gas would provide near Earth gravity and would float at an elevation where the outside pressure is about 1 atmosphere. This would make the structure less expensive than many proposed orbital habitats and the planetary atmosphere above the floating habitat would be shielded from solar radiation by the planet.

Not being a planetary scientist, I wondered out loud whether such a floating city could exist in the atmosphere of a Gas Giant. I do know that the density of the atmosphere around Jupiter varies from a faint trace at the outermost edge (like the atmosphere of Earth) to crushing pressures deep down. Although I admit that it may not be possible, it is not unreasonable to wonder whether an airship of breathable air at human comfort temperature could be made to float at some depth between the outer trace and the crushing depths of a gas giant. If it could, then it would be reasonable to also ask what the gravity would be at this altitude and would the atmosphere protect the airship from radiation? I do realize that the Jovian Airship would probably be more like a submarine – designed to resist outside pressure rather than a simple bag of air in equilibrium.

As to why I pointed the article out to you, the “specific problems” that you mentioned included:
1. it's at least as hostile as a corrosive hellhole
2. the atmosphere is full of hydrogen that seeps into everything,
3. if the grav plates holding up the colony fail then everyone plummets to their doom.
4. you've got pretty major radiation levels,
5. ridiculously strong winds
6. the generally high gravity makes it more of a pain for ships to enter and leave.
The article did address hostile corrosive atmospheres (1), a buoyant city has no grav plates (3), and radiation (4). So at least half of your original issues were discussed in the article. In addition, items (5) and (6) could be affected by altitude or choosing a gas giant other than Jupiter.

The additional information provided in your follow up post makes it unlikely that this would work in a hydrogen atmosphere. The next logical question is what other world/atmosphere/orbit combinations could it work on? How large can a rock world get and how thick of an atmosphere can be formed by out-gassing from the crust? What is the gravity and lift at 1 atmosphere on this hypothetical world? Here your opinions could be constructive rather than merely mildly dismissive (ok, if my idea will not work, then what will?)

 

[Malenfant]

The problem with an air balloon on a GG is that it's always going to be much denser than the surrounding atmosphere. You can have all the pressure in the world, but if the density of the surrounding material is still lower than that of the air in the balloon then it's still just going to sink like a rock. I'm not sure that there's any survivable depth where the hydrogen is compressed enough to allow an air balloon to be neutrally buoyant.

As another possibility, the Venus balloon city concept would probably work on a rocky world with a Dense, High (D) atmosphere (though you might need to have it more like a huge zeppelin, with the city attached as a gondola below a lighter-than-air gas balloon).

But gas giants are a different kettle of fish altogether. Even the smaller ones aren't nice places to be (IIRC Neptune had some winds clocked at about 1000 km/h recently).

I have to admit, I probably wouldn't feel all that comfortable living in a big balloon buffetting around in the atmosphere of an acidic hellhole...

 

[Liam Devlin]

Originally posted by starflash:
Very Interested, I've been doing a lot of house rules and scenario stuff for Megatraveller for a lonnnnng time... good idea, sorry if this seems late, I've been in Baghdad

HooAH! Welcome back from the front, brother. Glad to have you in one piece. What part of the City of Sin were you in?

 

[TheEngineer]

Hi !

Well, you could try to build a (very) rigid hull constructon filled with standard pressure atmo as buoyancy unit.
E.g. at considerable atmo depth, where the outside pressure is around 300 times standard value a typical real world balloon sized thing (e.g. 5000 m³) could provide 130 minus weight of construction tons of lift.
Now the problem is to find a point, where outside pressure/density is high enough to cause lift, but still low enough to let your construction survive

At least undersea cities are canonical in Traveller, so perhaps the pressure and material issues are solved here...

But as Mal already noted, I could think of many places more comfortable than this one.

As for Atpollards question for gravity and lift:
Gravity is not relevant, as its a proportional factor for both weight of a construction and the buoyancy lift.
Venus atmo should have a density of 1,4 kg/m³ here (normalized to a temperatur of 273 K). Helium would have 0,18 kg/m³. So any volume filled with helium would provide around 1,2 kg lift per m³.
If the weight of the supporting construction at least equals the lift the thing floats.....

A very basic problem might be, that good lift need thick atmo and thick atmo often means high atmo energy density = fierce wind conditions ....

And regarding the gravity problem, isn't Saturn a bit more comfortable here ?

regards,

TE

 

[Space Cadet]

Originally posted by Malenfant:
</font><blockquote>quote:</font><hr />Originally posted by SGB - Steve B:
ATP's question about wether or not a similar concept would work with a Gas Giant is interesting since in a traveller scenario a colony around and in a gas giant makes a lot of sense.

I'd be curious to know why you think a gas giant colony would make a lot of sense. As an environment it's at least as hostile as a corrosive hellhole - the atmosphere is full of hydrogen that seeps into everything, and if the grav plates holding up the colony fail then everyone plummets to their doom. Also you've got pretty major radiation levels, ridiculously strong winds (usually hurricane-force minimum if a storm comes through) and extreme weather that makes the worst of what we have on Earth look like a light breeze. Plus the generally high gravity makes it more of a pain for ships to enter and leave. [/QB]</font>[/QUOTE]Hydrogen is not especially toxic, the main danger is that of an explosion if it mixes with the breathable air in sufficient quantity. The solution is fairly simple, instead of trying to stop the hydrogen from leaking in, you simply scrub the hydrogen out of the air by forcibly combusting it. If you circulate the air through a compressor, that compresses and heats the air, the trace amounts of hydrogen will combust with free oxygen, decompress the air and the result is air with a little extra water vapor in in more than there was before.

The air you breath is not a lifting gas on Jupiter, so you simply heat hydrogen within the gas bag so that it is less dense than the surrounding hydrogen on the outside. At the temperatures prevalent on Jupiter, the interior gas doesn't have to be especially hot, room temperature would do, and within the hydrogen envelope, you have a much smaller gas bag that contains breathable air, at the same temperature as the warm hydrogen surrounding it The most obvious energy source would be a fusion reactor.

As far as radiation goes, the biggest source of radiation at the one bar atmosphere would be the fusion reactor. The Van Allen belts of Jupiter don't descend very far into the Jovian atmosphere. Where the radiation meets the atmosphere, the charged particles decellerate producing Aurora Borealis near Jupiter's North and South magnetic poles

 

[Space Cadet]

The thing is, a floating bouyant city is just another kind of space station, the airplanes that fly in the atmosphere are other kinds of space ships. If just happens that to get around in a gas giant's atmosphere, all you really need are portable fusion reactors, they heat the gases in hot hydrogen balloons, and the provide the motive force for jet engines that propel airplanes. Fighter combat would be "Star Wars" like, you have a definite up and down, you can have dog fighting, modern air warfare is mostly about shooting missiles though. Saturn would make a good backdrop, since the gravity is nearly right.

If you like adventuring in the corridors of spaceships and space stations, and you like atmospheric fighter combat, then the atmosphere of a gas giant could be the place for you. You even have weather, it is much the same as space stations and starships though. If you want a more naturalistic setting, Pulp Version of Venus might suit better, as might a truly alien planet orbiting another star.

 

[sgbrown]

Originally posted by Space Cadet:
The thing is, a floating bouyant city is just another kind of space station, the airplanes that fly in the atmosphere are other kinds of space ships. If just happens that to get around in a gas giant's atmosphere, all you really need are portable fusion reactors, they heat the gases in hot hydrogen balloons, and the provide the motive force for jet engines that propel airplanes. Fighter combat would be "Star Wars" like, you have a definite up and down, you can have dog fighting, modern air warfare is mostly about shooting missiles though. Saturn would make a good backdrop, since the gravity is nearly right.

If you like adventuring in the corridors of spaceships and space stations, and you like atmospheric fighter combat, then the atmosphere of a gas giant could be the place for you. You even have weather, it is much the same as space stations and starships though. If you want a more naturalistic setting, Pulp Version of Venus might suit better, as might a truly alien planet orbiting another star.

I concur - but that's the beauty of traveller - you don't have to stay with one or the other, you can have both.

 

[Blue Ghost]

Hunter; I'm still interested in a limited license, but what all will it entail? What I mean by that is if I want to produce "Traveller key chains" or somesuch, can I get a license for that?

Thanks much for any reply.

 

[Blue Ghost]

Whom do I contact to purchase and/or negotiate a license? What kind of contractural limitations are there?

Thanks much.