Gas giant mining

[abomination]

You can't actually use the vacuum of space to pull up the hydrogen because things don't work that way. I'll explain:

The reason a straw works is because when you reduce the pressure in the straw, the atmospheric pressure on the top of your drink pushes the drink into the straw. If you sealed your cup and had only the straw coming out, you couldn't suck up any liquid. (Unless your glass was flexible, like when you use those little milk cartons and close the top on your straw, or when you suck on a water bottle that doesn't have a good enough vent - when you suck in, the sides of the container collapse.) Likewise, if you were in a vacuum, you couldn't drink an unsealed container with a straw, though you could squeeze the container, effectively providing your pressure through mechanical means instead of gas pressure.

Another way to think about it - if a tube in space could suck away a small amount of atmosphere, then a really big tube could suck away a whole lot of atmosphere. What if the tube were as big as the whole planet? Since we still have an atmosphere, empirically the vacuum of space won't suck away an atmosphere.

Doh, I hadn't thought of that. Can't suck harder than a vacuum. But you can push stuff up from below

The bigger the hose, the more gas it can move.



I suggested plasma, since you could use magnetic fields in the tubes to "pump" it up. But mostly because I thought a giant pulsing tube of plasma would look cool, and the whole gas mine idea has "Rule of Cool" written all over it.

or some sort of mechanical device pushing gas past some sort of one way valve. Which isn't as pretty.

 

[Rigel Stardin]

As a kid (Many many many moons ago), I watched an experiement where they attached a balloon to a hose, placed it in a chamber and reduced the air pressure around the ballon. The ballon inflated because there was no pressure surrounding the outside of it?

 

[hdan]

As a kid (Many many many moons ago), I watched an experiement where they attached a balloon to a hose, placed it in a chamber and reduced the air pressure around the ballon. The ballon inflated because there was no pressure surrounding the outside of it?

Yes, but the hose didn't have to lift that air into a much higher potential energy state. In fact, the weight of that air pushed into the balloon, in a way going "down hill", until the elasticity of the balloon matched the pressure of the air.

If you stick a straw into a glass, does the water spout out the top? The water between the surface of the glass and the end of the straw weighs more than (and is obviously denser than) the air at the other end of the straw, yet it can't push the water up.

But if you put the end of that straw (say it's a bendy straw or something) LOWER than the top of the glass, the water will flow up and over, ultimately winding up "down hill". (The Siphon effect.)

Which gives me an idea - if you put a gravity generator on one edge of the siphon calibrated to a higher force than the planet you're siphoning from, things might work out. I'll let those better at physics than me work that out...

 

[aramis]

Siphoning only works if you can get pressure to lift it in the first place.

 

[Rigel Stardin]

My limited knowledge of real world science suggest that sticking a straw into a basketball would force the air out straw because of the pressure inside the basketball. Yes I know atmospheric pressure is putting pressure on the outside of the ball as well which inturn aides in the release of air from the basketball.

(Warning: Discovery Channel Science involved

One documentary on volcanic lakes in Africa stated that gases form layers in these lakes and if a landslide disrupts these layers the lake turns overs. To stop this from happening, they inserted a tube into that layer which cause the gases to be released using the pressure of the water.

The thought here is gas gaint atmospheres are at a higher density than earth atmosphere. Striking the right layer would allow the hydrogen to be expelled using the weight of the atmosphere to push the gas up the pipe to the station.

Question: Would a platform placed in geocentric orbit also provide force through rotation to pump the gas upward?

 

[Icosahedron]

My 2Cr:
Orbital elevators and tubes are probably an interrim tech if they ever prove feasible at all. IMO, once grav propulsion is matured it will supplant any such devices.

H&S-free drone or remote-piloted fuel shuttles (of whatever size you like) can bring fuel up to an orbiting station (in close orbit, so reducing time and effort) using off-the-shelf components rather than manufacturing a specialised tube.

And a hull fracture on a shuttle results in a single vessel leaving the conveyor belt, whereas a hull fracture on a tube could result in half the tube plummeting into the murky depths...

And you could use the shuttles for surveying, or use them as launches, or lifeboats, or mount a turret on them to help defend the station, or...

 

[HG_B]

The thought here is gas gaint atmospheres are at a higher density than earth atmosphere. Striking the right layer would allow the hydrogen to be expelled using the weight of the atmosphere to push the gas up the pipe to the station.

You are forgetting that gravity is pulling it towards the planet. The pressure would have be strong enough to propel the weight of the column of gas to greater than escape velocity. Not gonna happen as there is no pressure vessel in the 1st place

 

[hdan]

My limited knowledge of real world science suggest that sticking a straw into a basketball would force the air out straw because of the pressure inside the basketball. Yes I know atmospheric pressure is putting pressure on the outside of the ball as well which inturn aides in the release of air from the basketball.

The walls of your basketball are trying to contract. The air in the ball prevents that. If you place that ball in a vacuum, the air will flow out to the lower energy state.

In the case of a planet, the gravity is holding in the air. If you put a straw into space, the gravity will still hold in the air since "higher up" is a higher potential energy state.

Otherwise, you could build a perpetual motion machine by making a 50 mile high tower and mounting a wind turbine in it.

One documentary on volcanic lakes in Africa stated that gases form layers in these lakes and if a landslide disrupts these layers the lake turns overs. To stop this from happening, they inserted a tube into that layer which cause the gases to be released using the pressure of the water.

Right. It is just the same as your basketball example.

The thought here is gas gaint atmospheres are at a higher density than earth atmosphere. Striking the right layer would allow the hydrogen to be expelled using the weight of the atmosphere to push the gas up the pipe to the station.

This really does all come down to why does an atmosphere stay on a planet? If pressure was what held the air down, then sure, the straw thing would work. But it's not pressure holding "in" the atmosphere, it's gravity, which is working on all the air, all the time. Those "sea level" experiments where you create a vacuum work because you are at roughly the same gravitic potential, and you are making a lower pressure zone than would normally exist at that altitude.

I hope I'm explaining this correctly. (And even more so that I'm actually not mistaken myself.) You can't make a "more vacuum-y vacuum" in orbit. Right inside the edge of the atmosphere (where you can still measure air pressure), you could make a vacuum, but the amount of "suck" you'd get out of it is very slight compared to what you get down in the thicker parts of the atmosphere. And since gravity is holding the atmosphere in place, the best you could do is slightly de-pressurize the upper parts of the straw. And even that involves YOU doing the pumping, not a gusher effect.

Question: Would a platform placed in geocentric orbit also provide force through rotation to pump the gas upward?

An interesting question. My supposition is that no, it wouldn't work unless the planet was spinning very quickly, but I was never any good at centripetal acceleration calculations.

 

[aramis]

No, the geostationary orbit would NOT work; if the planet was spinning fast enough for the gas to rise, it already would have risen. Same issue as a siphon.

 

[hdan]

No, the geostationary orbit would NOT work; if the planet was spinning fast enough for the gas to rise, it already would have risen. Same issue as a siphon.

Doh, of course.

 

[Rigel Stardin]

So we are left with only one option then.
...The Rule of Cool...
Converting the Hydrogen into plasma and sending it up to the tanks in orbit.

Power requirement?

Using the planet's magnosphere, reactor or solar?