Why isn't SpaceX trying to create a floating sky colony on Venus? It makes much more sense than colonizing Mars

>Gas mining cloud city

vs

>moisture farmer

>Though some folks have been talking about ways to burn off and solidify Venus's atmosphere via chemical chain reactions. Awhile after that, it might start looking more inviting.

>Though some folks have been talking about ways to burn off and solidify Venus's atmosphere via chemical chain reactions.

Wow just, sounds quite ambitious. How are they planning to go about that?

>Wow just, sounds quite ambitious. How are they planning to go about that?
inverse tachyon pulse from deflector

I think I recall a sci-fi or two where they did that, but conveniently never explained how. The only way I could think to do it would be to build a giant moon-size shade somewhere out in front of it, then it'd freeze and the CO2 would liquify, bringing the whole thing down.

But then it'd be too cold - I dunno, maybe you could poke holes in it afterwards until you found a happy medium, or something. Still gotta deal with that Venusian day that lasts two-thirds of an Earth year though.

Think it'd almost be easier to terraform the damned moon - certainly easier to work with Mars than Venus.

I love this thread. It's beautiful and comical, it captures the heart of Veeky Forums.

something something your mom's dildo

Dude, stop it.

You have to make machines function well at high heat and pressure,mine resources with surface rock that's like taffy due to the heat, then you have to launch the mined substances from the surface up to your colony in the clouds, using what kind of rocket? You ever try to get a rocket to take off in several hundred degree heat under massive steel crushing pressure,and plow through a cloud layer of sulfuric acid?

You are hand-waving like half a dozen brain-poppingly hard engineering challenges.

SpaceX isn't trying to colonize Mars, they are 'building the railroad' to Mars/Venus.

Why would you use a rocket instead of a balloon or a propellor plane, dumbass
It's not a vacuum

Don't try to act like 450 celsius is some insane temperature, or that 100 atmospheres is an impossible to account for pressure.

We have sent probes to Venus's surface, the only problem is that conventional electronics can't function at high temperatures

>Also, the atmosphere at 50km above Venus (which is where the ambient temperature is equal to Earth sea level) is at around 70 degrees CELSIUS, not fahrenheit.
You would float higher than 50 km due to CO2 being quite a bit denser than air, at about 55 km. At that height, temperatures are like 27°C, which is still a bit high, but you may just as well settle for a lower cabin pressure (like on air planes) and go for a higher altitude and lower temperatures.

I think it's a cool idea, but nothing that sounds too practical. All in all a bit more practical than the mars shit I've heard so far.

High temperatures, lightning, 900+ atmospheres of pressures, chlorine, acid rain, and nearly a full G worth of gravity well.

The dozen or so landers we've sent to Venus have had a whopping 15% success rate, all half melted after landing, a none lasted as long as expected (save one atmospheric probe that was never intended to survive at all). All the atmospheric data we've gotten back since then indicate it was a miracle those few made it at all. It's a seething chemical ocean of hell down there.

temp/pressure unless you're wearing a suit.

then pressure.

>and nearly a full G worth of gravity well.
please tell me more about this incredibly dangerous full G of gravity thats on venus.

>900+ atmospheres of pressures
It's 90

I'm trying to imagine building a balloon sturdy enough to deal with the winds that you'd encounter in Venus's atmosphere. We're talking wind that's much denser that our wind moving at 450 miles per hour. How in the fuck can you take a balloon or a propeller craft through that?

It's a tall order m8. Mars has its issues,but they're a hell of a lot less severe than delaing with that mess of bullshit.

You aren't physically going down there period! 90 atmospheres is enough trouble in plain old water - this is basically hot acid on crack with lightning in it. It's the equivalent of diving into 3,000 feet of heated turbulent battery juice.

In case you're wondering what makes all this space travel so damned difficult to begin with - it's mostly this this called escape velocity. Getting on and off the moon or Mars is a hell of a lot easier than getting on and off the Earth or Venus. And you could imagine what would happen to your average rocket that has to exit THAT atmosphere at roughly the same speed it'd need to exit Earth's.

>We're talking wind that's much denser
What is that even supposed to mean

>wind moving at 450 miles per hour.
Top speeds are more like half of that, at much higher altitude than you would float and only at the equator. You don't really need to go for the equator though.

Also, the winds are not particularly turbulent, so you might just as well float with the winds to emulate some kind of day/night cycle.

>What is that even supposed to mean
Atmospheric gas under high pressure is denser than gas under less pressure, it has more mass in a given area and accordingly more inertia. A 50 mile per hpur wind on mars could barely even be felt by a person, a 50 mile per hour wind on the surface of venus would flip you around like a rag doll.

>>We're talking wind that's much denser
>What is that even supposed to mean
He means you're fighting against the equivalent of water, rather than air, and it's moving faster than air or water ever does on Earth. None of the few landers that made it down there landed anywhere near where intended, and they were basically just lumps of steel.

The balloon is not on surface level you dolt

NTG, but following the thread back, was this not in regards to mining the lava surface? Somehow going down or coming up with a magic super balloon?

Then it's even less of a problem as winds are only strong in the upper atmosphere. At surface level there is hardly anything going on.

Why do you think WIND is any different than an aircraft flying forward at 200 mph+

Surface winds are much slower, also wind is free power if you can harness it

You would anchor yourself to the surface, then use bouyancy to get up into the winds, then use aerodynamics to get up to the 55km altitude that your normal habitats are at

Cuz it's not wind anymore - it's more like a river, traveling at 400+mph against you.

At 90 atmospheres, an average of 10Km/h is nothing to sneeze at. Imagine what 10Km/h is like under 3,000 feet of water, as that's basically what you're looking at, except in the case the water is basically charged acid and you're basically sitting on lava. Chunks of Venera 13 weighing over a dozen kilograms rolled away before she stopped filming - months before she was supposed to.

Now put up a balloon (that can somehow take that churning chemical mass and not attract lightning and that you're somehow inflating against 90 atmospheres of pressure) and see where the hell you end up.

Not to mention this surface is essentially liquid, and the tectonics have been dead for half a billion years, so anything that might be useful is going to be sunk in ordered sedimentary layers. This means you'll have to tunnel through miles and miles of the same uniform liquid siliceous rocks before you find anything. All while dealing with that acid rain, torrents, pressures, hoping your drill doesn't overheat, and hoping that same semi-molten rock doesn't swallow your whole rig - before you even begin thinking on how to get it all back to Lando's Cloud City.

It's a CO2 atmosphere, with traces of Sufuric acid, at 450 degrees, at 90 atmospheres

This is something that can easily be tested on earth

Maybe use nukes to blast away to useful minerals.

>guy who founded multiple successful start-ups is a moron

Actually it turns out it's not just CO2 and Sulphuric Acid - it's also Chlorine, and several nasty combinations of all of the above to varying degrees depending on where you land.

Dropping nukes in into silicon jello isn't going to be particularly effective, plus it's just gonna make shit even hotter with no way for it to cool.

I dunno... For testing... Maybe you can try drilling for oil inside a deep enough inside an active undersea volcano to duplicate the pressure and heat problems, and just forget the corrosive chemical composition and the "winds" (probably more accurately described as "flows"), but suffice to say, we don't have the tech to even attempt that now. No place on Earth provides those kind of pressures, heat, hazardous chemical, and speed of flow in combination. All the Venera probes were tested in every way we could conceive at the time, and it turned out to be far from sufficient.

Really, in terms of engineering feats, it'd be easier to build a giant shade and cool the whole planet off first than to drill down in that hell and bring anything useful back to its exosphere. Space elevators aren't an option on a planet with a rotation that slow.

So either figure out how to build moon-sized aluminum sheets that don't collapse under their own gravity nor get rip to shreds by solar winds - or just go back to Mars, where mining and lifting is even easier than it is on Earth.

>>high heat
500°C isn't even hot enough to melt aluminum.

>>pressure
we have robots and submarines that can withstand 1070 atm of pressure, pressure really isn't much of an issue.

Temperature is a bigger issue because actuators are more difficult as magnets don't work very well at these temperatures and traditional semiconductors stop working above 300°C.

First has largely been solved and electric drills have been tested in Venusian ambient: lpi.usra.edu/vexag/may2008/presentations/22JIExtreme.pdf

Second, basic silicon carbide semiconductor technology has been demonstrated to work at venusian conditions. A SiC ring oscillator worked fine for 21 days(as long as they were willing to run the test) at venusian ambient conditions.

arstechnica.com/science/2017/02/venus-computer-chip/
aip.scitation.org/doi/10.1063/1.4973429

>>mine resources with surface rock that's like taffy due to the heat
Bullshit. Nothing from the Venera probes indicates that rock on venus' surface behaves like taffy:
articles.adsabs.harvard.edu//full/1984LPSC...14..393S/0000393.000.html

>>using what kind of rocket?
balloons. A metal bellows balloon(pic related) can reach altitudes where plastic doesn't melt, from there a teflon coated(to resist the sulfuric acid clouds) kapton balloon can be used to reach ~55 km which is about the altitude our colony would be at.
solarsystem.nasa.gov/docs/KERZHANO.pdf

>Cuz it's not wind anymore - it's more like a river, traveling at 400+mph against you.
It's not 400 mph at ground level, it's 400 mph at 70 km height or something. People have already corrected that for fuck's sake and you still keep repeating it.

Ya gotta get down there first.

Then ya gotta deal with ~10kph flows at 90 atmospheres - you do realize that's faster than any water at that same atmospheric depth moves on Earth without dropping a nuke or a volcano into the mix? Nothing of any structurally significant size could survive being it by it at an off angle, much less navigate it.

We know very little about the atmospheric gradients of Venus and the potential for turbulence and transient surface winds exists. A brief flash of 100 mph wind on the surface would tear pretty much any vehicle to shreds. We need way more data before we can try any of this.

That thing looks complicated and flimsy and it's dealing with insane external pressure while needing to be lightweight enough for the whole affair to actually be able to float.

You're acting like this is easy. It isn't. Robotically harvesting resources from the surface of Venus would be incredibly difficult. We're at least 15-25 years away from being able to give it a shot. Mars is much easier.

>>chlorine
in the form of hydrogen chloride, 0.1-0.6 ppm
>>acid rain
not at the surface, it's too hot for sulfuric acid to exist at the surface.

>>nearly a full G worth of gravity well.
no jello babies

>> 15% success rate
you pulled that number out of your ass didn't you? Venera 3: communications failed 2 weeks before landing, fail
Venera 4: ran out of battery before reaching the surface, fail
Venera 5 and 6: crushed before landing. Fail.
Venera 7-13: Successful landing
Pioneer Venus: wasn't supposed to survive landing but did anyway

That's 8 successes out of 12 missions, with one mission that wasn't supposed to be a lander for a success rate of about 67%.

>>half melted after landing
500°C isn't even hot enough to melt aluminum. The only thing that melted was the solder joints in the electronics.

> hydrogen chloride
> not hydrochloric acid
why?

Who needs to colonize a planet when you can live in a biosphere floating through space. You can fly by nearby planets, scan for resources, collect resources and off you go again.

Why isn't SpaceX trying to mine asteroids? It costs a shit tonne of money to send resources into space so why don't they focus on using what's already floating around?

en.wikipedia.org/wiki/Asteroid_mining#Potential_targets

Musk's business model seems to be pandering to the reddit crowd about being NASA 2.0 while he laughes his way to the bank to cash in his government subsidy checks

This faggot is right.

The first person to get a ship to Psyche and start building ships out of asteroid iron is going to become the god emperor of the asteroid belt.

If it were me,I'd get myself and a few hundred people on a good O'niell cylinder, and then i'd blow up a bunch of shit in earth's orbit and make it suicide ot try to follow me.

Musks dream is to build an amusement park on mars, You're all just pawns in his goal of achieving it.

>mfw I claim Anteros and become a space trillionaire

>>insane external pressure
the pressure differential isn't that much. Sure the absolute pressure might be be 90 atm, but the pressure differential between the inside and outside is only 630 millibar.

>>lightweight enough for the whole affair to actually be able to float.
Venus' atmosphere is quite dense at these altitudes. Someone did the math and found that a number of rocket stages ought to be neutrally buoyant at 5-15 km:
selenianboondocks.com/2013/11/venusian-rocket-floaties/
ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110016033.pdf

>tfw no Martian empire that purges dumb Earthlings
I WANT MY MARTIAN FANTASIES TO BE REAL

well, she is the love goddess for a reason

Mining and refining the resources you need in space, in addition to being a pain in the ass itself, does run the risk of someone picking up on the fact that it isn't all that hard to bring 100 ton bricks of semi-precious materials back home, and crash any market. (Possibly both literally and figuratively.)

Ask all those conquistadors who brought back all that gold back from the new world, and then died in destitution, how well that went for them.

Granted, most of those rocks are made up of mostly iron and carbon with a mixture of nickel, iridium, palladium, platinum, gold, magnesium, with a sprinkling of osmium, ruthenium and rhodium... So there's only so many markets you can crash that way, I suppose.

Dude, stop.

Even if electronics work as you say(which they won't, you are asuming perfect systems)what they won't stand is the constant degradation, erosion and all fuckery of high presure.

And electronics are just part of the equation that you will have to compensate with huge redudancies so you aren't sending another mining probe every month because the last one just fucked up something and you just can't let it work anymore(its not just that electronic components fail and stop working, is that they fail and the machine keeps working and making things worse)

And you have to lift those resources, lets see.

>Earth like gravity that forces you into taking high care of mas in a place where you won't have the infraestructure to do so.
>Superdense air with storms at certain altitudes adding even more complications for anything trying to reach orbit again.
>Total dependence in teleoperation, adding even more costs and points of failures.

Meanwhile Mars.

>Almost no atmosphere, no drag either.
>Lower gravity, which means that things are easier to put in orbit.
>People and tools can be close to each other, making things even cheaper.
>Much less agresive enviroment, even the radiation is not that huge issue(if it were, we wouldn't have space travel in the first place)

I swear I hate venufags, they are like the macfags; feeling so special because they think they are geniouses that have realized about something no one ever did.

>27°C still a bit high
No offense, but I bet you use Fahrenheit, or am I missing something here? 27°C is colder compared to your average day in summer. It wouldn't pose any threat to the hypothetical Venus atmospheric cloud balloon-structures that OP is talking about. That temperature would be ideal.

the pressure, unless you had no oxygen mask, then it would be not being able to breathe.

>Why isn't SpaceX trying to create a floating sky colony on Venus? It makes much more sense than colonizing Mars.
No it doesn't, the technology required to set up a self sustaining colony on Mars already exists the hurdles are doing it and paying for it, the technology to colonize venus meanwhile still does not exist.

>O'niel cylinder
How would you actually get one of those into space?

I'd say drowning, followed by angry gondoliers.

>Why isn't SpaceX trying to mine asteroids?
That would be much easier to do if every mission to them didn't have to escape earths gravity well first would it not?
Colonizing and setting up refueling stations on mars opens the rest of the system up a bit.

I'm German you twat. 27°C is a little high considering those people are living in a literal greenhouse. You need a negative temperature gradient to cool shit. You kind of want to end up with room temperature.

No water in the atmosphere

Why aren't we sending probes to the moons of Neptune and Saturn. Some of these moons have a much better chance at sustaining life than mars or Venus.

The only other planet we will ever be able to inhabit is one that is in a different solar system.

Better whip out that meme drive

>put shades on venus
>atmo freezes in a decade or two and you can start your work

Why is noone doing this? Fuck mars, it's a gay micro world.

Space Catapult.

>Germany bringing the bants

While I think, as fantastical as it sounds, this is actually more practical than mining the surface under the current conditions, in the end, what you end up with is worse than Mars. No water.

Does have the advantage of 1G, but there's more disadvantages to that than advantages. On the other hand, the surface would be a lot smoother, so landing and getting around would be easier, but then again, the minerals would be striated, meaning you'd have to dig a long ways through the same stuff (probably miles of silicates) before you found anything else. It wouldn't be like Earth or Mars where materials would be mixed in and in veins.

Setting up on Mars first would probably be wiser, but it maybe one day, when we have the ability to make semi-super structures, coming back to Venus and cooling it off might be an idea.

underrated

>the technology to colonize venus meanwhile still does not exist.

Humans have been flying blimps since the early 1900's

And what resource are they going to exploit that generates a profit?

Making statements about mineral availibility before we actually go see for ourselves is fucking stupid
Geologists can't make accurate predictions about the EARTH UNDER THEIR FEET

Why would you imagine they could make predictions about Venus or Asteroids

Everything needed for an initial colony can be extracted from the air anyways.
Water is present in the atmosphere, and other hydrogen compounds

Fuck this stupid "colonize planets" meme

When are we going to get a space station that isn't a flying hunk of shit?

They make predictions on asteroids based on meteorites remains.

They make predictions on Venus based on the analysis we've made so far, coupled with the state of the surface, and what we know about how geology works on Earth.

The problem with Venus is that much of its surface is in a viscous state. That means heavier elements sink and larger aggregates come to the surface. We know the surface is thus, as one would predict, entirely silicates, largely semi-molten. What we know about hot rock suggests this should continue for a long ways before you hit a layer of another element. (Though, on the plus side, once you do hit said, the deposit should be large and fairly uniform. So mining is at least more predictable.)

And there's no water in the surface, and insomuch as there is any in the air, it's 0.002% water vapor, compare that to the Earth’s atmosphere at 0.40% or 0.16% on Mars. So, even if you collapse the atmosphere on Venus, you aren't getting oceans.

That's what I was thinking. Hellish it might be but you don't need to make it earth clone of earth, and it certainly can become more suitable long term colony than low g worlds.
The lack of hydrogen is a problem but nothing that can't be solved with few meters of delta v and carefully planned neptune gravity assist...
I think that's actually easier than the solar shade which requires relatively basic self fabrication, but self fabrication nonetheless.

At any rate, terraforming is a giant undertaking but sometimes people inflate the difficulty to fantastical levels and usually time scales. Moving planets or doubling Mars's mass for example is not realistic. Melting some co2 or putting a big ass umbrella in space is actually possible.

The gravity is more of a disadvantage than an advantage though. It makes it require exponentially more escape velocity than Mars. You can't use a space elevator as, in addition to the normal problems Earth-scale gravity causes, the planet's rotation is much, much too slow.

On Mars, however, unlike Earth or Venus, space elevators maybe a feasible thing.

Bone loss isn't a real issue at Mars gravity, the muscle mass loss can be compensated for. Jello babies aren't as much as a problem as folks like to think. Even in zero-G, small mammals seem to gestate fine, regain even their ability to balance after being returned to normal gravity in short order, and the reduced strength isn't an issue provided you never intend to return to your ancestral homeland. If anything, it just means more calories can be dedicated to the brain.

But if it were a problem, getting on and off Mars is a whole lot easier, so there's nothing stopping you from rigging up a satellites with artificial gravity that a mother would spend the last few months of her pregnancy on and where a newborn would spend perhaps its first few years.

Granted, as others have pointed out, in terms of ease of use, O'Neil cylinders are superior to either planet, and you can mine resources from asteroids. They are, however, engineering nightmares, and probably impossible to make at the scales that the surface of an entire planet gives you. To have a definitive survival advantage, they also have to placed at quite some distance from the Earth. Not that self-sustaining habitable space stations aren't a worthy goal, but they'd probably have to be in addition to, rather than instead of, planetary colonies.

Like so many of these arguments, it's not an either/or situation. Different groups will no doubt focus on different projects as industry expands and improves.

What sort of rock is melting at under 500 degrees
There is active volcanoes and tectonic activity on venus

Our knowledge of Earth stops where the land surface ends, everything below that is guess work or experimental drilling.

Venus is a whole planet, it would be stupid to suggest that the whole planet is a uniform layered ball.

Rocks absorb heat and it doesn't dissipate well at 90 atmospheres, which is why much of the surface looks like this. Much of it is semi-molten, and even where our probes landed, they sank quite a bit (resulting in some of the failures). No probe that has landed on Venus has reach its operational life goal - unlike those on Mars which have regularly exceeded their live goals by multiple magnitudes.

There hasn't been tectonic activity on Venus for at least half a billion years. It is true there are volcanos that are probably redistributing stuff, but that also makes it harder to pick safe mining spots, while the chaotic flows make it impossible to determine where you're going to land... But it's true, if you collapse the atmosphere via cooling that may help with the striation issues.

Wrong pic...

>The lander functioned for 127 minutes (the planned design life was 32 minutes) in an environment with a temperature of 457 °C (855 °F) and a pressure of 89 Earth atmospheres (9.0 MPa). The descent vehicle transmitted data to the satellite, which acted as a data relay as it flew by Venus.

We are working on electronics today that will be able to function at 500 celcius, which is the primary difficulty for venusian landers

There are large "continents" that would exist at lower pressures & lower temperatures too

Like I said before, until we get there to actually do prospecting, saying that no mineral resources are accessible is just guess work.

If the whole damn planet was semi-molten liquid then it wouldn't have mountains.

>escape a gravity well
>refueling stations on mars
I hope you mean in orbit around Mars

But wait, Mars orbit still wouldn't be great, because you'd have to limit yourself to trajectories that let you do Mars orbital insertion before going somewhere else. Even that costs delta-V. And you still have to find a way to make the fuel, even if you have to land tanks full of hydrogen on Mars.

Earth-orbiting stations have the advantage that you already have to go through there on the way to escape. And it's getting up there that takes most of the fuel anyhow.

As far as terraforming goes, I'm seeing one common thing in the most straightforward ways to terraform Mars and Venus: build an enormous shield in front of each of them, to block light from Venus, and charged particles from Mars.

>Never watched si-fi movie where sciencists use a blackmans train with a plasma drill to dig to the core of the Earth to drop nuclear bombs on it causing it to spin again.
Minerals are easy to mine on Venus.

>floating sky colony on Venus?
whats the point, why not just orbit earth

>easy
atmosphere surface pressure same as 1km deep water, how the fuck is that easy

>despite all evidence pointing towards Venus being clearly the worst option, it is actually the best

nah

the upper atmosphere of Venus is a siren's song luring you into """literal hell"""

>false color image that looks like lava
>must be lava

Except it isn't. Venus' surface rocks are not semi-molten, they aren't even hot enough to glow red. Basalt (the most common type fo rock on Venus) needs to be about twice as hot as the surface of Venus in order to start going even slightly soft.

Why doesn't SpaceX just put a really tall mountain on Venus and then build a colony on the summit?

Cuz half the shit that'll kill the Earth will may kill any self-sustaining orbital habitat in the process, plus it's much more tempting to fudge "self sustaining" when you're that close.

Why you'd wanna sink yourself into a gravity well just as strong where extracting resources is a whole lot harder than near anywhere else in the solar system and the more critical ones are plain old missing, that, I've no idea. You would be better off setting up an O'Nieil in the asteroid belt than in the exosphere of Venus - at least until you cooled it, and got a whole lotta water there. Mars is more difficult to depart from than an O'Neil cylinder, but easier than Venus, and still gives you basically limitless electronics-friendly land mass to play with, unlike the cylinder where you're limited to your engineering constraints.

kek

>The ONLY actual problem in mining on the surface is electronics operating at high temperatures, which will be solved fairly soon
No it won't.

Guys, listen
What if
Listen
What if we sent big robots to Venus,
Guys
If we sent big robots there, and built a giant 70 km tall mountain?
We could live on top of it right?

The mountain will need to be made out of husks of dead robots.

with space magic

fyi rocks will become white-ish long before glowing red in the process of heating

I have read a lot about terraforming Mars. But even if you managed to do that, you can never terraform the gravity of the planet, so truly colonizing Mars will never happen. Maybe by genetically modified humans that can deal with the low gravity, but not by normal humans.

But in what way could you terraform Venus? I guess "cooling" a planet is much harder, than "heating" it?

>>Dude, stop
can't, don't have any brakes

>>Even if electronics work as you say(which they won't, you are as[s]uming perfect systems)what they won't stand is the constant degradation, erosion and all fuckery of high pres[s]ure.
We have tested silicon carbide integrated circuits for 521 hours at venusian ambient conditions, yes including the corrosive gases, no degradation was found.
Didn't you read the linked paper?

aip.scitation.org/doi/10.1063/1.4973429

pic related

>>Superdense air
launch from higher altitudes

>> with storms at certain altitudes adding even more complications for anything trying to reach orbit again
well then, don't launch a rocket from those altitudes. Now since you seem to know so much about this, perhaps you can elaborate as to what these altitudes are?

NASA has concluded that it can be done:
ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20160006329.pdf

>>Earth like gravity that forces you into taking high care of mas[s] in a place where you won't have the infraestructure to do so.
On Mars you need pressurized habitats and radiation shielding, ''in a place where you won't have the infraestructure to do so"

>>Total dependence in teleoperation, adding even more costs and points of failures
Provided one can make a sufficiently strong fullerene cable, one doesn't need teleoperated robots, one can dedge for rocks.

But material from the surface may not be that important as a variety of elements can be extracted from Venus' atmosphere

gonna finish the rest of my response later

By building it from materials launched by a mass driver on the Moon

Make it from nickel iron asteroids, that have been nudged into earth orbit by remote rocket drones. Get the resources to come to us.

Does Mars have enough nitrogen? I know Venus has shitloads, assuming you removed the co2 you'd get about 3 bar atmo in which you could joyfully hike with oxygen mask, but I remember reading Mars has the issue of not having enough.

>I guess "cooling" a planet is much harder, than "heating" it?
Yeah.

Earth and Mars both used to have thicker, volcanic CO2 atmospheres too, but since they're cooler planets, this CO2 was absorbed into geological sinks via weathering (and in Earth's case, photosynthesis also played a role). On Venus, however, the temperature was already hot enough that the reverse happened, and carbonate minerals readily rejected their carbon into the atmosphere. (Or that's the prevailing understanding anyways.)
en.wikipedia.org/wiki/Carbonate–silicate_cycle

Perhaps if the Venusian surface could be terraformed into enormous mountains reaching into the cooler upper atmosphere, this reaction would reverse and CO2 would be absorbed into silicate rocks at the peaks of these mountains.

>Does Mars have enough nitrogen?
What do you mean, "enough nitrogen?" What do you need nitrogen for? If atmospheric pressure is below 0.3 atmospheres nitrogen's not going to do you any good anyways.