Atmospheric Mining For Mars - Veneran Siphon

[nrrusher]

As a brain exercise.....(I am not interested in whether or not this will be done, or if anyone thinks it isn't worth the trouble discussing).........I would like to consider the possibilities of a mining operation on Venus described as follows.....<br /><br />Utilizing the L1 and/or L2 positions (possibly both), and having a tubular pipe, in the spirit of a space elevator running from an aerial base in the upper Veneran Atmosphere to a counterweight/collection station just beyond L1 and L2.<br /><br />I know L1 for Venus/Sun is about 1,000,000 kms from the surface of Venus, so I would assume L2 would be about that in the other direction, though I am not sure, still looking.<br /><br />The tubes could be any size, or larger and smaller from end to end, doesn't really matter, so that can be adjusted depending on strenght requirements. Be it 3 inches, or 3 meters in diameter.<br /><br />What I would like is some mathematical help with the strain on the entire system - i.e. the weight a counterweight would have to support - the effects on the largely carbon dioxide mix while it is being siphoned up, etc.<br /><br />One interesting idea is, could it be engineered such that once the process is started and gas/liquid is flowing out the ends, would you even need to power the suction, or could the siphon take over?<br /><br />Also, L1 would be in sun sight, so I would assume the heating of the tube could be managed to maintain the gaseous state. However, on the L2 side, would being in perpetual darkness cause the whole thing to soldify? How would either situation be managed?<br /><br />So, we need for starters<br /><br />Weight of gas in transit (lets assume a 1 ft diameter tube just for arguments sake) over a ~ 1,000,000 km length.<br /><br />Power Requirements to start it<br /><br />Siphon characteristics, if any.<br /><br />Strenght required of hose and the forces acting upon it.<br /><br />Etc.<br /><br />Any other info if known would be good to know....such as exactly what L1 and L2 distances

 

[MeteorWayne]

Bottom line is, a pipe from the atmosphere to space has the same pressure inside the pipe as the atmosphere beside it.<br />With no pressure differential, there's nothing to make it work.<br />So you are going to be pumping whatever gas you move.<br /><br />Then, what would you do with all that CO2 and sulphuric acid, even if you did spend gobs of energy continuously sucking it into space? <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[nrrusher]

<br />I do not believe you are correct on the siphon. just like sucking from a gas tank here, the momentum of the fuel past a certain point will pull what is coming after.<br /><br />Once the gas reaches L1 and L2 it will start to "flow downhill" so to speak, and pull from above. Obviously, this would require a certain distance of tube/volume of gas past those L points, which is the point of the counterweight as well. If you had half again as much mass being pumped through past the L point as you do below it, that would effectively handle 1/2 the suction requirements.<br /><br />The point is to do double duty here. From L2, the resulting barge could be "flung/whipped" towards Mars with some assistance, of course. This would help out with the over-thick atmpos. of Venus, and the under-thick atmos. of Mars.....<br /><br />NR

 

[nrrusher]

<br />From what I understand regarding strength, although Venus has .9 X earth's gravity, since gravity decreases at an exponential rate the further out you go, the strength requirements on a Veneran Elevator like this would be significantly less than on Earth, and it therefore decreases at a faster rate as you move out.

 

[nrrusher]

<br />Now that I think about it, from the "L' point on out, lets say 500,00 kms, you could pre-fill the pipe with a heavier inert gas that would then pull up on everything below once the system is opened up. The very end could be opened to space, allowing the vacuume there to do the sucking. Once the inert gas has flowed through entirely, being sucked out by space, the flow could then be diverted into the barge transport containers with minimal additional energy.<br /><br />To temporarily stop the flow, a valve could be place precisely at L1, and it could close. Provided it is a sealed system, that would shut the flow down until a new connection could be made.....<br /><br />NR

 

[MeteorWayne]

Sorry, the siphon effect won't work for the reason I stated. It's physics <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[nrrusher]

<br />Ideally, we would want the CO2 to be in a solid state during transport to Mars, but getting it to the transport would be easier as a gas. So, once out of the tube, it would be best to let it freeze, I suppose. It would then require insulation from the sun while it was being shot toward Mars so it didn't try to gasify and cause pressure problems.....<br /><br />NR<br /><br />From what I understand about carbon nanotubes, they have much stronger tensile/stretch strength than they do compression. With this in mind, the lower 1/2 of the tube would need to be fairly small so as to be able to resist the collapse pressure from the suction, let's say 1 inch diameter for starters.<br /><br />On the other side of the L point, the pressure will be positive instead of negative, so the tube could be made much larger, and therefore it wouldn't have to be as long either, while still holding the same mass as the lower half of the tube.<br /><br />

 

[h2ouniverse]

Sorry nnrusher, but this is not the momentum of the liquid that makes the liquid flow in the siphon. You need to inspire not to set the liquid in motion but to make it fill the part of the siphon that is below the upper reservoir. (*) It is the pressure differential that makes the liquid flow. In your case there is none.<br />The lower part of a space elevator weighs downwards.<br /><br />(*) Try it yourself: instead of risking absorbing the liquid you want to syphon (generally not drinkable), rather pre-fill the hose from one extremity to the other, put your fingers on both ends to prevent it from draining. Plunge one end into the upper reservoir. Then place the second end below the level (with a margin) and remove your finger.

 

[nrrusher]

<br />Yes, I understand. Siphoning is basically letting gravity create a suction. GIVEN - Provided the tranfer is sealed, the mass of material moving "down" the tube needs to weight more than the material moving "up" the tube at any one time.<br /><br />That is why I said that the tube needs to go PAST the L point a significant distance.....the point being to make sure that the total mass past L point at any one time is greater than the mass below it, toward Venus.<br /><br />If you STOPPED immediately at the L point, you are right, there would be no suction at all, but if you go PAST it, there will be an increasingly powerful suction on the whole system.<br /><br />The L1 system would use the Sun's gravity to pull it up. Past L1 the sun's gravity is increasingly stronger than Venus's, so the gas would effectively be falling "down" toward the sun, and with a sealed tube, woud therefore be creating suction on everything below L1. Once you have MORE mass past L1 than below it, the siphon would take over......<br /><br />L2, not using gravity, but the reverse momentum of the centrifugal force via the spin of Venus around the sun, I am not sure exactly how long/how much volume would need to be past L2 in order to create the siphon....but at some point there would be one.<br /><br />Please, if I am wrong, tell me WHY. I am not a physicist (my dad is a physics professor, so I will speak to him later) but I do believe this will work as I describe.<br /><br />NR<br /><br />

 

[nrrusher]

<br />Is there anyplace on this forum that I can draw or post an image to better show what I am thinking???<br /><br />NR

 

[telfrow]

You can attach it to a post. Just make sure the file is a jpg under 100kb and not wider than 640 pixels. <br /><br />Make sure the "I want to preview my post and/or attach a file." is checked and then hit "Continue." You'll see your post with a "Browse" button it. Find your file and attach it. Then hit "Continue." The file will be uploaded and we'll approve it for you.<br /><br /> <div class="Discussion_UserSignature"> <strong><font color="#3366ff">Made weak by time and fate, but strong in will to strive, to seek, to find and not to yeild.</font> - <font color="#3366ff"><em>Tennyson</em></font></strong> </div>

 

[h2ouniverse]

For a siphon to work, you need incompressibility. With a gas, you can create a vacuum. This occurs naturally above Venus. The column of gas over any point of Venus is in equilibrium, with pressure from 90 bars on surface decreasing down to zero in space. Venus gravity is such that the few hundreds of kilometers of atm thickness are enough to allow transition from 90 bars to 0. This cannot get higher, as vacuum would be spontaneously created in your pipe at that altitude.<br /><br />And if you fill your tube with a liquid, you will make explode your recipient at bottom. (this is called Pascal's barrel experiment). For water, this is 1 bar every 12 meters on Venus. A 120km column of water will exert about 10000 bars at its bottom. (and Venus' gravity is pretty much the same at such a low altitude)<br /><br />The slope (and depth) of Venus' gravity well is far too large.<br /><br />Best regards.

 

[mithridates]

I thought of a similar idea to this myself but I was thinking of something about 50-80km in length that channels air from the surface to the cooler upper parts. The siphon method wouldn't work but since the winds are so powerful up there there's no reason why they couldn't be used to power a propeller/propellers to force the air upward. <br /><br />(I hope nobody pokes a hole in this idea now) <div class="Discussion_UserSignature"> <p>----- </p><p>http://mithridates.blogspot.com</p> </div>

 

[MeteorWayne]

I give up. <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[vogon13]

Yeah,<br /><br />I don't know whether to laugh or cry.<br /><br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[mithridates]

Hm? That was regarding what you wrote before:<br /><br /><blockquote><font class="small">In reply to:</font><hr /><p>So you are going to be pumping whatever gas you move. <p><hr /></p></p></blockquote><br /><br />I.e. a method for pumping the gas. I realize you post quite prolifically here but that was a rather flippant response for something that addressed the very point you brought up. <div class="Discussion_UserSignature"> <p>----- </p><p>http://mithridates.blogspot.com</p> </div>

 

[billslugg]

OK - I got it. Here is the deal. You must pump the gas from Venus up to the L1 point. If you had a pipe from Venus up the L1 point, open at the end, with a perfect vacuum at the end, the gas is not going to flow up the pipe. If it did then it would flow with or without a pipe, which it does not, therefore the gas will not flow up a pipe with one end in a planet's atmosphere and the other end out in space in a perfect vacuum.<br /><br />Once you get the gas to the L1 point then it would flow by the Sun's gravity. Since the pipe is being held fast at the L1 point, all portions of the pipe toward the Sun are at an orbital velocity less than what's needed at that point to stay in orbit, therefore the pipe and anything in it will fall toward the Sun.<br /><br />The portion of the gas in the pipe toward the Sun from the L1 point will not suction the portion of the gas between L1 and Venus, since we have already demonstrated that a perfect vacuum condition at L1 will not result in the gas rising from the planet to L1. Since there is no vacuum better than a perfect vacuum, the siphon will not work. <div class="Discussion_UserSignature"> <p> </p><p> </p> </div>

 

[kelvinzero]

Hi nrusher,<br /><br />We discussed these sort of ideas in these two related threads. MeteorWayne is right about the straw idea not working, however there were alternatives.<br /><br />The gist is that there might be ways of collecting the very very thin atmosphere in low orbit, but then you also have to find a way to recover momentum without expending more propellent than you collected, for example an ion drive or an electrodynamic tether.<br /><br />If you could do this, you could deliver atmosphere gasses especially oxygen to orbit much more cheaply than by launching it.<br /><br />http://uplink.space.com/showthreaded.php?Cat=&Board=businesstech&Number=704268<br /><br />http://uplink.space.com/showthreaded.php?Cat=&Board=tech&Number=689131

 

[nrrusher]

<br />Although I am still not convinced/understand why it cannot work, I SINCERELY appreciate those who are trying to explain it to me.<br /><br />(remember, this is as much as an exercise for me in order to understand a few things in general about gravity, gases, etc., so if this is nuts, no big deal)<br /><br /><br /><br />One thing that I haven't apparently been able to get across is the fact that the hose would NOT stop at L1 or L2....but would have a length of hose after that point, and would likely grow significantly bigger in diameter as after it went past L point in order to increase the mass of gas after L point in as short a distance as possible.<br /><br />Also, the pipe would not just be hanging limp at some point out in space, but be part of a closed and managed system. Opening it up to the vacuum of space would just be to get things flowing....<br /><br />That being said, from what I have been able to research, some of the main issues that this would encounter would be that fact that gas compresses, therefore the weight of the column of gas required to pump the L1 and below portion full would be considerable....i.e. the bottom of the hose would have to have very thick walls.<br /><br />Also, the temperature would obviously be a concern as CO2 would freeze at a certain point.....does anyone know if CO2 goes through a liquid state from gas to solid??? I did not believe it did, but wasn't sure.....it has been a while since chemistry.<br /><br />Final Question.......<br /><br />To narrow things down a bit/bring us to the same page, what will happen in this situation.....<br /><br />We have constructed the tube, with the required strength - it is 6 inches INSIDE diameter from the atmospheric level to L point (lets say L2) and from L2 out to end....(lets say that is another 800,000 kilometers), it increases gradually in inside diameter to about 6 feet<br /><br />The outside diameter, especially at the bottom, is rather large in order to contain the pressures....lets say a few d

 

[mental_avenger]

The point you seem to be missing is that there is no such thing as suction. What you are referring to as “suction†is really a pressure of zero at one end of the pipe and a pressure of about 90 bar at the other end. If that pressure on the low end was able to push the gas up the tube into space, then the entire atmosphere would have been pushed into space long ago.<br /><br />There are two principles that defeat your plan. The first is that you cannot create a siphon effect in a gas. You need a liquid for that. Secondly, the pressure at the bottom of the pipe would have to be able to overcome the gravity of Venus. Clearly it does not, as is evidenced by the fact that Venus still has an atmosphere. There is nothing magical about inserting a pipe into the equation.<br /> <div class="Discussion_UserSignature"> <p style="margin-top:0in;margin-left:0in;margin-right:0in" class="MsoNormal"><font face="Times New Roman" size="2" color="#ff0000"><strong>Our Solar System must be passing through a Non Sequitur area of space.</strong></font></p> </div>

 

[kelvinzero]

Hi nrusher,<br />Sorry I think I missed your point before. You are using a pump at the bottom, not suction at the top?<br /><br />That might work <img src="/images/icons/smile.gif" /> <br /><br />It would still take energy though.<br />hmmm.. actually I had just assumed that from assumption that surface of venus to L1 required input of energy regardless. I didnt actually check the maths.<br /><br />The syphon still wouldnt work, but if we built a necklace of compressed air capsules tied with some sort of unobtainium thread so long the loop could stretch so near the sun that you were in a lower potential spot than venus's surface, then yes it could be self powering <img src="/images/icons/smile.gif" />

 

[tdamskov]

Since you've practically built a space elevator anyway, why not extend it the last few km's to the ground? Here your solar powered factory can extract and compress CO2 into high pressure capsules. Each capsule is then hauled on the space elevator to your lagrange point.<br /><br />Not only would this lessen the requirements to the structural integrity of the tether but also allow you to bring up other materials from the ground.<br /><br />I believe siphoning will only make sense if you're trying to capture the atmosphere of a gas giant - and in this case you might want to consider some kind of powered tether capable of ionising and accelerating gas along the tether.

 

[nrrusher]

Ok, the vacuum higher up in the pipe is not enough to pull up the gas versus the gravity of Venus. I can accept that, and can see the logic of it. Also, introducing the centrifugal force/whip effect to the system of a pipe extended well past L point in a closed system does not help enough to counteract this either. Despite the momentum imparted to the gases by the rotational force of Venus by the Corialis effect, it, along with the vacuum does not overcome gravity. - point taken..........<br /><br />So...... <img src="/images/icons/smile.gif" /> the only way to overcome this is to calculate how much additional force would be required to force the gas up, and apply it in some other additional fashion, in addition to the vacuum pressure and whip effect. <br /><br />(Although I can concede the vacuum and whip by themselves are not enough to pull the gas upward, I do still believe they would help some, at least the whip effect anyway will....)<br /><br />So, in addition to the primary pump at the bottom, there may need to be additional ones spaced throughout the distance to L1. The vacuum and whip effect will help, but will not be enough by themselves to "siphon" the gas. The additional pumps would effectively behave like stair steps, getting the gas over the hump that the vacuum and whip effect cannot. The pumps would be farther apart and/or smaller as you move up the pipe, since the amount of force required would decrease the further you go up.<br /><br />That much I can concede.....is there anything still wrong with this analysis besides the obvious difficulty of building the thing????<br /><br />Thanks,<br /><br />NR<br /><br />

 

[nrrusher]

<br />I did not see the last two posts before I wrote the last one....... (didn't realize there was another page)<br /><br />Anyway, the reason I left it hanging in the upper atmosphere is because of the pressure and temperature at ground level being so nasty.....why add that addtional problem when then gas is just as easily obtained further up?<br /><br />Also, if a method of manufacturing for carbon nanotubes on the scale requierd could be fabricated to work on an aerial plaform in the Veneran atmosphere, it would be much easier to deploy from there once built.<br /><br />Thanks to everyone though - I am over the hump in my brain that wanted to believe that a siphon/vacuum effect would dramatically assist in moving the gas upward. I can see now why that would not be nearly enough....<br /><br />NR

 

[nrrusher]

<br />I like the idea of the high pressure/compressed capsules. That would make more sense. The only real advantage to the other system is if the vacuum priniciple, along with the whip effect, would asisst much, but if they do not help enough, then a solid transport system in the spirit of the space elevator would make more sense....