How will we terraform Titan?

[kerbiloid]

7 minutes ago, MinimumSky5 said:

places in the solar system that you can find free nitrogen

Mars has it, too.

Probably, Pluto and Triton.

[DDE]

11 minutes ago, Spaceception said:

and release all of its methane as gas - which we'd probably need to take out.

Which is a non-trivial affair.

Makes me wonder if a runaway greenhouse would lead to a bubble of steam and gaseous methane instead of a water world.

11 minutes ago, MinimumSky5 said:

Just to point out, there are exactly three places in the solar system that you can find free nitrogen:

I’d look for potassium if I were you.

Edited December 30, 2018 by DDE

[Nivee~]

15 minutes ago, MinimumSky5 said:

If you're going to build habitats for people, or terraform planets, you need that nitrogen. We obviously don't want to take nitrogen from earth, so Titan would be exporting nitrogen to the entire outer solar system. The methane is nice for plastics, but not the most valuable resource there. 

Exactly what I was talking about! And Venus has 3% nitrogen in its atmosphere, but that's more massive than the entirety of nitrogen in Earth's atmosphere!

26 minutes ago, DDE said:

Because if there’s no-one to buy at either point, or there are cheaper places to buy, there won’t be a trade.

I admit, graphene is still in early stage of research. There are potential applications in aerospace, construction, possibly electronics. Today graphene is synthesized from graphite. But if we are at a point in human history when we are seriously talking about deep space travel, then we would need that ultra strong, ultra light material, in megatons!

Earth has only this much of graphite available, and if you want more carbon then Venusian atmosphere has lots of it. A floating industrial complex that would manufacture graphene by siphoning off the CO2 in Venusian atmosphere. That graphene would be used for every major space project at that time.

So yeah, folks at outer planets would need lots of graphene, and Venus might just be the planet where the first 'trillionaires' are created.

 

Or it could be all a dud and 50 years later I will be telling sci-fi stories to my grandchildren about colonizing Mars...

6 minutes ago, DDE said:

I’d look for potassium if I were you.

Its on our Moon. Moon is rich in KREEP elements (Kalium(potassium), Rare Earth Elements and Phosphorus)

12 minutes ago, kerbiloid said:

Mars has it, too.

Just a lil... and we would colonize it first anyways, so we dont want to take away any pre-existing Nitrogen from Mars.

Pluto and Triton have a really sparse atmosphere and are TOO far away. Venus is very close in comparison!

Edited December 30, 2018 by Nivee~

[kerbiloid]

How big are the biggest graphene constructions to be sure if it can be used for large structures.

How fast are they degrading under the space radiation, compared to metals?

13 minutes ago, Nivee~ said:

Venus is very close in comparison!

delta-V

[Bill Phil]

1 hour ago, MinimumSky5 said:

Just to point out, there are exactly three places in the solar system that you can find free nitrogen:

Earth

Venus

Titan

If you're going to build habitats for people, or terraform planets, you need that nitrogen. We obviously don't want to take nitrogen from earth, so Titan would be exporting nitrogen to the entire outer solar system. The methane is nice for plastics, but not the most valuable resource there. 

Don’t forget gas and ice giants. Ammonia clouds and whatnot. Not really great for extracting though.

Also some asteroids and outer moons likely have nitrogen. Ganymede for example may have ammonia.

[DDE]

1 hour ago, Nivee~ said:

Earth has only this much of graphite available, and if you want more carbon then Venusian atmosphere has lots of it.

The Belt also has it, and you don’t need to play gymnastics with baloons to get it. dV costs probably end up lower.

1 hour ago, Nivee~ said:

and we would colonize it first anyways, so we dont want to take away any pre-existing Nitrogen from Mars.

That’s a dangerous assumption to make. Permanent space exploitation will be dictated by resource gathering; it’s not immediately clear if permanent settlement would happen at all.

[Nivee~]

59 minutes ago, kerbiloid said:

Delta-V

Venus needs less delta v than Mars...

[kerbiloid]

A funny thing. To use nitrogen you almost always have to first turn it into ammonia. So, the free nitrogen doesn't mean a lot.

3 minutes ago, Nivee~ said:

Venus needs less delta v than Mars...

Venus needs 10 km/s to put the loot into LVO.
Mars just ~4 km/s. On Mars you can even use  reusable SSTO.

Edited December 30, 2018 by kerbiloid

[Nivee~]

2 minutes ago, DDE said:

it’s not immediately clear if permanent settlement would happen at all

Eh, like i said, it could all just be a dud and a mars mission would still be scifi 20 years later.

Doesn't hurt to dream though..

1 hour ago, kerbiloid said:

How big are the biggest graphene constructions to be sure if it can be used for large structures.

How fast are they degrading under the space radiation, compared to metals?

Graphene is terribly expensive to manufacture at 100$/cm2, so a lot of research has not been done yet. But structures will be most likely massive , as it can be used for a Mars orbital tether.

[kerbiloid]

1 minute ago, Nivee~ said:

Graphene is terribly expensive to manufacture at 100$/cm2

Iron is everywhere. Aluminium too.

[Nivee~]

3 minutes ago, kerbiloid said:

Venus needs 10 km/s to put the loot into LVO.
Mars just ~4 km/s. On Mars you can even use  reusable SSTO.

Woah woah no ones going to the surface! CO2 can be scooped from the upper atmosphere..

[kerbiloid]

2 minutes ago, Nivee~ said:

Woah woah no ones going to the surface! CO2 can be scooped from the upper atmosphere.

Ok, this saves 100 m/s.

Or are you going to gather it from a satellite?

Edited December 30, 2018 by kerbiloid

[Nivee~]

1 minute ago, kerbiloid said:

Iron is everywhere. Aluminium too.

They have been around for a long time, there presence didn't stop us from making further advances in material science to make better materials. 

Oh! A funny story! Aluminium was at one time considered a precious metal, because its extraction from the ore was so difficult. But once froth floatation method was developed, aluminium could be extracted cheaply, and as a result we now have long range airplanes.

Graphene costed 10 times as much as now to make in 2012, cost could fall further with refinement of the manufacturing process.

3 minutes ago, kerbiloid said:

Ok, this saves 100 m/s.

How did you reach that number? I would assume delta v saved would be much more than that, since Venusian atmosphere is at NTP at about 55 kilometers. And from the surface, it would take about 27000 m/s to reach LVO, but that's not the point.

My point was to conduct atmospheric passes and scoop in CO2 and transfer it to an orbital manufacturing plant.

[kerbiloid]

8 minutes ago, Nivee~ said:

I would assume delta v saved would be much more than that, since Venusian atmosphere is at NTP at about 55 kilometers.

OK, Venusian orbital speed is ~8 km/s.
+ 1..2 km/s for gravity,
+ say, < 1 km/s for air drag (otherwise how is the plant floating)
So, ~10 km/s to reach the orbit. And several more to send the cargo away.

[Nivee~]

4 minutes ago, kerbiloid said:

OK, Venusian orbital speed is ~8 km/s.
+ 1..2 km/s for gravity,
+ say, < 1 km/s for air drag (otherwise how is the plant floating)
So, ~10 km/s to reach the orbit. And several more to send the cargo away.

Oh! I thought you were talking about launching the cargo from the surface. 

But that's a moot point, we are talking about using the rare atmosphere in LVO to refill our CO2 tanks. Once manufactured in an orbital facility, the cargo would take about 3.5 km/s to launch into Earth intercept, and aerocapture at Earth.

[Espatie]

If you're on Venus and all you are interested in is the atmosphere, you can use a Cloud City.

[kerbiloid]

1 minute ago, Nivee~ said:

But that's a moot point, we are talking about using the rare atmosphere in LVO to refill our CO2 tanks. Once manufactured in an orbital facility, the cargo would take about 3.5 km/s to launch into Earth intercept, and aerocapture at Earth.

So, is the scoop installed on a satellite moving at 8 km/s through the thin upper atmosphere?

[Nivee~]

3 minutes ago, kerbiloid said:

So, is the scoop installed on a satellite moving at 8 km/s through the thin upper atmosphere?

Yup... ESA has studied a similar concept in LEO, to collect oxygen, while using Nitrogen as propellant in a 'air-breathing' Hall thruster to make sure perigee doesn't dip too much. This would most probably require a nuclear reactor though.

Edited December 30, 2018 by Nivee~

[kerbiloid]

6 minutes ago, Nivee~ said:

Yup... ESA has studied a similar concept in LEO, to collect oxygen, while using Nitrogen as propellant in a 'air-breathing' Hall thruster to make sure perigee doesn't dip too much. This would most probably require a nuclear reactor though.

The concept is nice.
Isn't every collected atom of the "air" pushing the sat back at 8 km/s speed?
Wouldn't it require a ISP*g  >8 km/s engine being permanently switched on to withstand the air drag?

Edited December 30, 2018 by kerbiloid

[Nivee~]

2 minutes ago, kerbiloid said:

Isn't every collected atom of the "air" pushing the sat back at 8 km/s speed?

Yes, it does. But the momentum (Mass x velocity) of the sat is much more than the *air* atom. Infact, the miniscule drag is the reason why satellites in LEO dont have a long life, unless there's periodic station keeping.

5 minutes ago, kerbiloid said:

Wouldn't it require a ISP*g  >8 km/s engine being permanently switched on to withstand the air drag?

Well, think of it this way, the ISS also faces a continuous atmospheric drag, but it only needs periodic reboost. The same with our satellite. It will hang around in LVO, with periodic (if more frequent) reboosts. I suggested the nuclear reactor because the satellite also compresses and liquifies the CO2, before transferring it to the orbital manufacturing station.

[magnemoe]

6 hours ago, Green Baron said:

Guys, there is absolutely no scientific base to assume we would "terraform" any planet with foreseeable tech. We have discussed this so often that i find it hard to see a point in doing this again. We cannot even raise the atmospheric pressure on Mars by remarkable levels, as has been shown with some scientific background.

We can, of course, express our fantasies on the matter.

Yes, this is obviously far future. However Titan has some serious issues like lower than the moons gravity and high faction of it being ice giving serious problems making Venus trivial. 

 

[kerbiloid]

6 minutes ago, Nivee~ said:

Yes, it does. But the momentum (Mass x velocity) of the sat is much more than the *air* atom.

As well as it's much more than a mass of any atom of the engine exhaust.
So, catching m*V from the air, you have to spend at least the same momentum to keep the sat from deorbiting.
This means a high-ISP engine constantly working, and a lot of dV in total. With such delta-V you can deliver the things from Titan.

6 minutes ago, Nivee~ said:

ISS also faces a continuous atmospheric drag, but it only needs periodic reboost

It's orbiting in very thin air, not sufficient to scoop it. And from time to time it has to raise the orbit with the propellant delivered from Earth.

6 minutes ago, magnemoe said:

Yes, this is obviously far future. However Titan has some serious issues like lower than the moons gravity and high faction of it being ice giving serious problems making Venus trivial. 

And if we hope to create a wormhole to get to another star, why not make a ti-i-iny hole to connect Titan and Venus with a bidirectional pipe?

Edited December 30, 2018 by kerbiloid

[Nivee~]

7 minutes ago, kerbiloid said:

It's orbiting in very thin air, not sufficient to scoop it. And from time to time it has to raise the orbit with the propellant delivered from Earth.

The ESA study assumed a 200 km circular orbit. ISS is at about 400 km orbit. And IIRC there was a proposal to use this orbit to collect LOX for orbital depots. I couldn't find any mentions of altitude where the exhaust velocity of the propellant cant match the atmospheric drag.

26 minutes ago, magnemoe said:

Yes, this is obviously far future. However Titan has some serious issues like lower than the moons gravity and high faction of it being ice giving serious problems making Venus trivial. 

Well, the tech involved in my assumptions is pretty near future (15-20 years, I guess). What's really needed is the push by the governments and other external factors... which is not happening anytime soon.

[Thor Wotansen]

I think we'd have a better chance of terraforming Venus than Titan, although with Venus's rotational period I don't much see the point of terraforming it.  If we do build up Titan, I see it as a computing center and data storage, since, as has been mentioned above, the temperature of Titan makes it pretty great for that.  As for building things on planets when it's much cheaper to build O'Neil cylinders and populate them with biosphere cultures from Earth, I really don't think it's something we'll be focusing on when we do start expanding.  Of course there are exceptions, like the nitrogen problem and perhaps some less common elements, but most of what we need to colonize the solar system is already floating about in the asteroid belt.  Also, the environment around gas giants is'n particularly inviting, when you consider the amount of radiation they kick out.

[DDE]

1 hour ago, Thor Wotansen said:

I really don't think it's something we'll be focusing on when we do start expanding

It's also rather telling that, over time, resource exploitation has required less and less people. Western Siberia, for example, isn't exactly one giant megapolis.