Blimp lighter than hydrogen....?

[scottb50]

I've been talking about operating in the atmosphere, I would think the same thing would work getting to orbit though. Hover off the ground and use air and Hydrogen until you switch to LOX and Hydrogen. <div class="Discussion_UserSignature"> </div>

 

[why06]

could we not suck whatever kind of gas is at LEO and use it for the zeppelin...there has to be something out there. Right?<font color="yellow"></font> <div class="Discussion_UserSignature"> <div>________________________________________ <br /></div><div><ul><li><font color="#008000"><em>your move...</em></font></li></ul></div> </div>

 

[mlorrey]

Very little something. It is a vacuum. There are maybe a few hundred molecules of hydrogen per cubic centimeter at most. The sucking would go in the wrong direction, all out. There have never been pumps that could pump that low a vacuum, primarily for the reason that you'd have to produce an even lower pressure in your pump to get whatever there is to enter your pump.

 

[why06]

I was very unclear and just flat out wrong. What I meant to propose is that whatever material the vacumballoon is planning to be made of can be stretched in space to a huge size than a current could be set up to keep it in place ounce it is dragged back to earth. This way no pumps are neccesary. The material would take up little overall space and would very light onboard the shuttle. I'm sorry, but heating the hydrogen, while a good idea does not seam as grat as creating a vacum.<br /> <br /><br />I was wrong in my last proposal because I thought there might be a gas lighter tha theren hydrogen floating around way up there.<font color="yellow"></font> <div class="Discussion_UserSignature"> <div>________________________________________ <br /></div><div><ul><li><font color="#008000"><em>your move...</em></font></li></ul></div> </div>

 

[mlorrey]

This proposal is also meritless. The problem isn't hydrogen vs vacuum, it is the ratio of each to the density of the oxygen/nitrogen atmosphere. <br /><br />Look at it this way: because the Nitrogen atom is 14 times heavier, and the Oxygen atom is 16 times heavier, given x many molecules of hydrogen vs equal molecules of N2 and O2, H2 molecules have approximately 2/29ths the atomic mass for a given atmospheric pressure than a normal atmospheric mixture of N2 and O2. The difference between 2/29ths and zero is so small that the mass of any structure you would need to maintain an absolute vacuum would be significantly in excess of that difference. It is thus most efficient to use Hydrogen.<br /><br />This also limits you: hydrogen lift gas is molecular H2, while most hydrogen in LEO is hydrogen ions, which are half the mass of H2 molecules. You would need to heat or otherwise turn your lift gas into a plasma of ionized hydrogen. Doing so would also allow you to minimize osmotic losses through the envelope, as you could positively charge your envelope, which would electrostatically bottle your lift gas and may allow you to fly with less mass inside than outside, while at the same time producing an electrostatic field outside that would repel hydrogen outside, possibly creating a larger virtual envelope described by the electrostatic field intensity.

 

[why06]

Isn't the original round blimp inefficient because ther is less contact surface in which the gasses can interact. In my mind the better blimp would be in the shape of a disc to create a greater surface to volume ratio. Also I'm not sure... did you say that this ideal would only work if the H2 problems were ionized. Is his a problem or a solution? How does this limit me?<blockquote><font class="small">In reply to:</font><hr /><p>This also limits you: hydrogen lift gas is molecular H2, while most hydrogen in LEO is hydrogen ions, which are half the mass of H2 molecules. You would need to heat or otherwise turn your lift gas into a plasma of ionized hydrogen. Doing so would also allow you to minimize osmotic losses through the envelope, as you could positively charge your envelope, which would electrostatically bottle your lift gas and may allow you to fly with less mass inside than outside, while at the same time producing an electrostatic field outside that would repel hydrogen outside, possibly creating a larger virtual envelope described by the electrostatic field intensity. <font color="yellow"></font></p></blockquote> <div class="Discussion_UserSignature"> <div>________________________________________ <br /></div><div><ul><li><font color="#008000"><em>your move...</em></font></li></ul></div> </div>

 

[mlorrey]

vacuum hydrogen in LEO is monatomic H+ ions with an atomic mass of 1. Ballon lift gas hydrogen is molecular H2, with an atomic mass of 2. Ergo, molecular hydrogen gas has twice the density of ionic hydrogen gas at the same atmospheric pressure. Thus, a H2 filled balloon will always be at the bottom of the H+ layer of the thermosphere. <br /><br />However, if you ionize the hydrogen in your balloon once you reach that point, you may be able to proceed to higher altitudes IF your hydrogen in your balloon is either hotter than the hydrogen outside, and you are able to use electrostatic effects to make your balloon envelope a bottle holding H+ inside at a high charge level you could reduce the pressure of H+ inside, thus reducing the mass of your balloon and thus increasing its lift capability. The same charge effect may work on the outside to repel exterior H+ from a region around the balloon, creating a virtual electrostatic balloon region void of hydrogen ions (or at least at lower concentration).

 

[nexium]

Apparently there are several kinds of ions, which may not even have names. In 100 volt gas (and vapor) tubes the electrons move to a higher, or lower orbit without changing the number of atoms per molecule. The density may decrease a little, but not half like hydrogen. Hydrogen may be an exception, as it only has one electron per atom. Other types of ions have lost one or more, or even all of their electrons. I suspect all of these ion types are found at an altitude of 200 kilometers, (perhaps even a very rare free quark) so the density is reduced perhaps 20% instead of 50% by the ionization. I suspect the density inside the balloon can be reduced by 20% by applying a very high voltage, but this will require some massive equipment and conciderable energy, which may offset all of the advantage. Neil

 

[mlorrey]

From my reading, the thermosphere seems to stratify ions by their molecular or atomic weight, which is unlike the lower atmosphere which is pretty homogenously mixed. Thus the lower atmosphere is also called the homosphere, and the upper atmosphere is called the heterosphere.<br /><br />Molecules like O2 and N2 break up when they are stripped of enough of their outer orbit electrons that they can't maintain the valence bond.<br /><br />However, the hydrogen ions are primarly captured from the solar wind as ions by the magnetic field and stripped of their velocity.

 

[jpowell]

Once you're in the thermosphere you're "already there". The challange is climbing out of the mesosphere.<br /><br />JP<br />www.jpaerospace.com

 

[mlorrey]

The challenge is going from floating to orbiting. There is a massive difference in potential vs kinetic energy levels.