SargeRho

We shouldn't Terraform Mars. There's very little in it for us, compared to the massive effort. Martian colonists, in turn, would have a good incentive to do it. It might also create industries in the outer solar system, because they'll need boatloads of Ammonia to do so.

I would actually hope to crash the prices, but not to the point where it's no longer viable. Because of how extremely useful these materials are.

Titanium, Platinum, and other Platinum-group metals, Neodymium...the whole high-tech metal palette.

Which is exactly what I've said.

To quote myself: "it has to be specially produced if you want to build any more RTGs."

Or you could use Fuel Cells. The Space Shuttle was powered by Hydrogen-Oxygen fuel cells, giving it a mission time of 2 weeks or so. The Apollo CSM was also powered by Hydrogen-Oxygen fuel cells, which was sufficient for the more than 12 days that some of the Apollo missions lasted. So, a fuel cell energy storage system would be more than adequate to sustain the base for the night. During the day, part of the solar power would be used to split the Water back into Hydrogen and Oxygen.

Yes, because fish consume oxygen that's dissolved in the water. Which comes from the air, or from algae and plants in the water.

Yes, using beamed power, which would only use electricity. The laser or microwave beams would be aimed at a heat exchanger on the spacecraft, which would heat hydrogen propellant. This engine would be 2-3 times as efficient as a chemical rocket, according to Escape Dynamics' test result, which is typical for thermal rockets. Purely electric thrusters have very low thrust, though, I think something on the order of 1 newton per gigawatt.

So that it doesn't create a debris field. Eventually it is going to fail, and when it does, it's going to break up, and shotgun LEO.

Because we're out of Plutonium-238, it has to be specially produced if you want to build any more RTGs.

You can build a space elevator on Mars, with current materials. That would require relocating Phobos though, you can also use a mass driver to shoot things most of the way to orbit. Mars could export materials, but also at some point culture, so, movies, games, books, as well as all sorts of scientific innovations. Also possibly spacecraft, once the colony is large enough?

That isn't going to help you against a meteoroids strike, not in the slightest. A rock smacking into the dome at 25000kph is going to rip a sizeable hole in it, no matter what it's built of. You'd need some sort of advanced tracking system that can detect and subsequently deflect them away from the dome. We don't have forcefields, yet.

If something pierces the dome, it's going to rupture and kill a lot of people very quickly, due to the high pressure difference. If something flattens a hab, only the people in that hab are going to be killed, not the whole colony.

Bad idea. I'm no engineer or architect, but triangles are absurdly strong. And everything else is rather weak. If you want to build a dome, you should build a geodesic one. Also, initially, a dome is a bad idea because it will get hit by meteors, until Mars has been terraformed to the point of having a thick enough atmosphere.

Ganymede and Titan have similar surface gravities to our Moon, so, if people can live on the Moon, they'll be able to live on Ganymede and Titan. If you don't mind living on a radiation-bathed volcano, Io has more gravity than the Moon

I'm not referring to oil as a fossil fuel, but as an extremely versatile resource, since we make just about everything from Oil.

The reason I say Titan is out of purely utilitarian motives: It's full of hydrocarbons, and has lakes of Methane. Rocket fuel and black gold all at once. Considering how insanely versatile oil is, I can see Titan being given some freedom and democracy soon

Titan. Or the underside of Ganymede's Ice crust.

The BFR is meant to be fully reusable, so it may well be considerably cheaper. A transpacific flight on an A380 doesn't cost 370 million dollars, after all, while burning a comparable amount of fuel in the process.

You'll need to import or mine some nutrients for plants, because not all necessary elements are present in Venus' atmosphere, unless you don't plan to expand the colony, ever. Phosphorus, Calcium, Iron, Magnesium, Potassium...these are literally laying around on Mars in the form of metal oxides, and in other forms on asteroids and the moon. Otherwise you will have to take recycling to extreme levels, more so than Mars or asteroid colonies, where you can afford wasting material, because it's right there. Hydrogen, Carbon, Sulphur, Oxygen and Nitrogen. That's not enough for a self-sustaining colony. And Venus doesn't offer anything that could possibly be exported economically. You can shoot things to Earth from the Moon and Mars using linear accelerators, and NEOs get close to Earth periodically, so you don't even need all that much dV to get things from Asteroids either.

I'm going to go off of 2 assumptions here. 1: We have some sort of super-heavy launch vehicle, such as the BFR. 2: Subsurface water ice is abundant, which appears to be the case. First of all, we need a reliable power source. A thermoelectric nuclear reactor would do the trick, or one using sterling engines or brayton turbines, which would be less reliable though. For a sustainable habitat, you need a source of nitrogen, water and oxygen first and foremost. Since water can be split to release oxygen, we have that part covered, and plants can convert CO2 into Oxygen, and the Atmosphere, as well as the soil, contain Nitrogen and nitrogen-rich minerals. Food will be mostly brought along by the colonists at first, until the greenhouses can provide all of their food. Next we need some way of keeping the first generation of plants alive. We can use the subsurface water ice, combined with imported nutrients for that. I think aeroponics or hydroponics would be the best candidate at first, since soil is heavy, and you'd have to import that from Earth at first. https://s-media-cache-ak0.pinimg.com/564x/8c/0f/36/8c0f367e1ac0181ebd5fa1d265700272.jpg Then we need a source of spare parts. Producing large mechanical parts shouldn't be much of an issue, since metals like iron, aluminium, titanium, nickel and manganese are very common on Mars. We'd have to develop a metalworks plant that can convert martian sand into useful metals. I don't know much about metallurgy though. Electronics would likely have to come from Earth for a while, as would smaller mechanical parts. The initial habitats would need to be brought from Earth. A good solution would be inflatable habs that are then covered in Martian soil, either in the form of sand bags, or via 3d printing, as ESA proposed for the Moon: http://lunarscience.nasa.gov/wp-content/uploads/2013/02/lunarbase3dprinting.jpg Now you have a Mars habitat that can keep its inhabitants alive, without having to import everything from Earth. Things that will have to be imported from Earth for a while, both on Mars and Venus, will be medical supplies, spare parts, and people. And of course space suits and vehicles. Another thing that would be very useful are lightweight spacesuits, perhaps mechanical compression suits, that allow the inhabitants to move around with enough freedom to be able to do stuff outside. Also a fuel plant, producing Liquid Methane and Liquid Oxygen rocket fuel, to refuel the landers to be sent back up, either right back to Earth, or acting as shuttles between some sort of space freighter and the surface. Space Freighter that carries large amounts of cargo between Earth and Mars, and/or Earth and Venus, would be very useful for just about any long term endeavour in space I think.

Solid ground in the case of Mars, and natural gravity in the case of Venus. Also on Venus you don't need to build radiation protection, even on Mars you need less than on an Asteroid. I, for one, wouldn't be able to live permanently in a space station or floating base.

blocking radio waves is easy, and they aren't ionizing, thus not causing cancer. X-Rays, Gamma Rays and Cosmic Rays are a different issue entirely, and very hard to shield.

IIRC Earth Alliance ships use some sort of Particle Accelerator engines, powered by Fusion reactors. --- Colonial Battlestars make some level of sense, while they have gravity carpet, the CIC/Bridge is buried deep inside of the ships, and they're full of CIWSes, and use Railguns as primary armament, also, unlike most sci-fi ships, the Galactica has maneuvering thrusters. The ships in The Expanse are fairly plausible, aside of the insane Epstein Drive.

I'm going to hijack this thread for my own devious endeavours for a second I'm looking for a good justification for "short" range battles, and by short I still mean in space terms, so, over tens of thousands of kilometers. What I have so far is that some sort of plasma shields were developed, that completely absorb laser weapon fire, as well as particle beams, requiring ships to get close enough to use nuclear and kinetic weapons, without those being intercepted or evaded before reaching their target.