While I'll accept that Venus may have a larger *total* amount of Nitrogen (given the relative atmospheric densities), that is completely irrelevant.
Not really when the operation is done in the scale of
practically inserting an entire atmosphere on another planet. You wouldn't want to ship Earth's nitrogen to Mars (what would be left on Earth?) and Titan is better off with its own atmosphere. Like I said, an outer solar system moon with denser atmosphere than Earth definitely has its uses, even if it is a tad bit cold for immediate colonization.
How do you harvest it?
Build large city-zeppelins that float in the upper atmosphere of Venus, lower risers/pipes to lower atmosphere, pump up the gas, separate the gases with either centrifugal or cryogenic methods. If they can generate a magnetic field and rip holes to space-time continuum, energy is the least of concerns in FreeSpace universe. Abundance of raw materials and construction costs of collecting/transportation units would be the limiting factor.
The hardest part of extracting the 78% nitrogen from Earth's atmosphere is that you have to throw out the CO2 and oxygen first as you cool and pressurise the sample.
- As we're also interested in liquid oxygen, we are throwing away less than 1% of the sample.
Yes - and moving significant volume to Mars would make an equally significant dent on Earth's atmosphere.
Remember that Mars has much lower surface gravity, so you need a much higher gas pillar to generate sufficient static pressure on the surface, so you need relatively large amounts of gas in that atmosphere...
Extracting the 3.5% Nitrogen on Venus would mean throwing out 96.5% of what you capture and process.
- Thus the energy budget is extremely high per unit of 'useful gas'.
Except that frozen CO
2 will definitely have uses as well. Inserting additional carbon and oxygen to Mars would also be beneficial. Not only would it warm up the planet, but plantation would eventually bind the carbon and release oxygen; however, GTA wanted more immediate results, therefore the bacteria was designed to produce almost exclusively pure oxygen to increase the
partial pressure of oxygen to levels where it can saturate human blood and avoid hypoxia after proper acclimatization to altitude, while raising
absolute pressure to levels tolerable to human soft tissues.
Prolonged exposure with no protective gear still can cause something like a full body love bite, so mechanical pressure suits and partially pressurized face masks with small compressors are often used especially for high performance tasks outside.
On Titan on the other hand, you are throwing out less than 2% of what you capture and process.
- Admittedly, it's mostly methane which is a bit 'gummy' to handle in liquid form, but that's really a cleaning challenge rather than a significant energy cost.
And, like previously pointed out, it's more useful where it currently is.
So really, you would be laughed out of the building for suggesting harvesting N2 from Venus - while there is a lot there in total, you aren't going to be able to *get* it.
Pay attention to the actual amount of gas in question.
Calculate how much gas would be needed to produce surface pressure of Earth altitude equivalent 2400-3000 metres on MArtian surface. Then calculate how much gas is in Earth and Titan respectively.
Venus is the best source of nitrogen (and CO
2) simply because there's
so much of it that it would be enough to provide atmospheres for Mars and all Jovian moons and still be too dense to make colonization possible.
If you suggested bringing it from Titan, they'd listen to you and then point out that bulk transport of atmospheric gases to try to bulk out the Martian atmosphere would take far too long to have any noticeable effect - either on the source or the destination.
- On the other hand, I have ignored the delta-v requirements. But those don't appear to apply in the FreeSpace universe anyway.
Yep, delta v requirements don't matter much in FreeSpace due to subspace. Energy of transportation and amount of transportation units matters more - they have limited amounts of ships so they would never be able to transport meaningful volumes
anyway, regardless of the source of the gas. That was the main factor that contributed to abandoning that plan.
Which is not to say that there's no activity on Venus...
