Hydrogen Farms

[More Boosters]

So, the sun constantly vomits material that could be used for solar sails, but as most of that is hydrogen, would "hydrogen farms" where ionized H from the wind is collected over time be worth it? Is there any merit to this idea or would the collection rate be too slow? I'm not talking about bussard ramjets, I'm talking about a station that generates fuel over time.

[Tex_NL]

I doubt the yield will be high enough to make it a viable option. Simply using solar energy to split water into H₂ and O₂ would probably be quicker, cheaper and easier.

But for the sake of argument lets assume the yield is relatively high. What would you want to do with all that H₂? Apart from using it as propellant in a NERVA or ion engine, without an oxidizer like O₂ it's pretty useless.

[Kertech]

Be incredibly simplistic style: pressurise it and blow it out the back -> monoprop...

Or I guess fusion, but you'd need a lot of other things 

Maybe put the JET in space then see

Edited February 3, 2016 by Kertech

[Wjolcz]

Yeah, I too think that getting hydrogen from solar power energy would be easier and cheaper. Also pollution free since using it as rocket fuel (with O2) creates water (and some heat).

[peadar1987]

If you're capturing hydrogen from the solar wind, you're also going to capture its momentum, which will tend to blast you away from the sun. You're going to have to counteract that with station keeping manoeuvres. Unless you have super-efficient thrusters that can accelerate the hydrogen to speeds greater than the solar wind, you're not going to break even

[AngelLestat]

you should be very close to the sun´s corona to harvester a "descent" amount, then you need to waste a lot of energy to transport that h2 to higher orbits.

If you dont want to spent propellent, then just use solar sails.

[sevenperforce]

While I admit that I'm not sure why you'd want to do this...

...one possibility would be to build a central collection chamber that feeds into a large reflective balloon. As the balloon is inflated by the accumulating hydrogen, it exposes more and more reflective surface to the sun, causing it to spiral to a higher orbit. Then it can dump its fuel at a depot and repeat the process.

[More Boosters]

6 hours ago, peadar1987 said:

If you're capturing hydrogen from the solar wind, you're also going to capture its momentum, which will tend to blast you away from the sun. You're going to have to counteract that with station keeping manoeuvres. Unless you have super-efficient thrusters that can accelerate the hydrogen to speeds greater than the solar wind, you're not going to break even

Doesn't matter if this is, say, a ground station on Mercury.

[Tex_NL]

17 minutes ago, More Boosters said:

Doesn't matter if this is, say, a ground station on Mercury.

Capturing hydrogen from solar wind on Mercury makes even less sense. Although Mercury barely has an atmosphere to speak of it is 22% hydrogen. Instead of capturing the solar wind it's easier to simply suck this up. And as an added bonus there is also 42% oxygen.
Hydrogen and oxygen. Now things start getting interesting. Now we have rocket fuel.

[PB666]

12 hours ago, More Boosters said:

So, the sun constantly vomits material that could be used for solar sails, but as most of that is hydrogen, would "hydrogen farms" where ionized H from the wind is collected over time be worth it? Is there any merit to this idea or would the collection rate be too slow? I'm not talking about bussard ramjets, I'm talking about a station that generates fuel over time.

Do a search, we have done the calculations, it would take millions of years to harvest enough hydrogen from the solar wind even at mercuries orbit to fill a hydrogen balloon, let alone harvest for use in .. .  anything.

The sun produces alot of hydrogen, true, but it does so over a very wide area and that hydrogen speeds away at a million km per hour, it eventually slows down as it runs into things and cools down, but basically blasts anything volatile in the inner solar system (e.g. why tails on comets point radial) its not alot of plasma, but anything moving at a quarter million meters/second is going knock the bejezus out of anything it hits. So eventually enough of this gas slows down out in plutos orbit to react forming ice and weird whatnot molecules of the outer solar system. This is where you harvest the hydrogen, but not real time solar wind, but condensates from the last 5 billion years. Theres not alot of it either, if there was new horizons would be toast, its found scattered on various protocomets out in the kuiper belt. The overwhelming majority of the hydrogen after spending a few weeks speeding away from the sun slams into the bow shock and ends up drifting out into interstellar space.

When you see reports of a plasma storm on the suns surface that is millions of degrees hot, think velocity as in not much substance but a hell of a lot of speed.

 

 

 

 

1 hour ago, Tex_NL said:

Capturing hydrogen from solar wind on Mercury makes even less sense. Although Mercury barely has an atmosphere to speak of it is 22% hydrogen. Instead of capturing the solar wind it's easier to simply suck this up. And as an added bonus there is also 42% oxygen.
Hydrogen and oxygen. Now things start getting interesting. Now we have rocket fuel.

Good idea, one side of mercury is unbearably hot, the other side is unbearably cold. But yeah mercury would be a good target for some brave explorer, if he can manage to land in a shielded valley whereby he can place a mirror and deflect some of that sun light for his use. Diffraction gradient also works. In these valleys there is ice on the valley floors, easier to mine ice than gas.

[AngelLestat]

harvesting hydrogen from mercury "atmosphere" will be pointless.
There is no way to suck..  because is not possible to low the pressure even more, even if you go fast enough with a scoop you will not accomplish much.

Someone needs hydrogen in space?  asteroids... those things made of ice...  there is no need to collect atom by atom.

[fredinno]

 

2 hours ago, PB666 said:

Do a search, we have done the calculations, it would take millions of years to harvest enough hydrogen from the solar wind even at mercuries orbit to fill a hydrogen balloon, let alone harvest for use in .. .  anything.

The sun produces alot of hydrogen, true, but it does so over a very wide area and that hydrogen speeds away at a million km per hour, it eventually slows down as it runs into things and cools down, but basically blasts anything volatile in the inner solar system (e.g. why tails on comets point radial) its not alot of plasma, but anything moving at a quarter million meters/second is going knock the bejezus out of anything it hits. So eventually enough of this gas slows down out in plutos orbit to react forming ice and weird whatnot molecules of the outer solar system. This is where you harvest the hydrogen, but not real time solar wind, but condensates from the last 5 billion years. Theres not alot of it either, if there was new horizons would be toast, its found scattered on various protocomets out in the kuiper belt. The overwhelming majority of the hydrogen after spending a few weeks speeding away from the sun slams into the bow shock and ends up drifting out into interstellar space.

When you see reports of a plasma storm on the suns surface that is millions of degrees hot, think velocity as in not much substance but a hell of a lot of speed.

 

 

 

 

Good idea, one side of mercury is unbearably hot, the other side is unbearably cold. But yeah mercury would be a good target for some brave explorer, if he can manage to land in a shielded valley whereby he can place a mirror and deflect some of that sun light for his use. Diffraction gradient also works. In these valleys there is ice on the valley floors, easier to mine ice than gas.

Mercury isn't tidally locked, so a collecting station would experience a very long night, making this much less useful.

1 hour ago, AngelLestat said:

harvesting hydrogen from mercury "atmosphere" will be pointless.
There is no way to suck..  because is not possible to low the pressure even more, even if you go fast enough with a scoop you will not accomplish much.

Someone needs hydrogen in space?  asteroids... those things made of ice...  there is no need to collect atom by atom.

The pressure differential is very slight, so it will be difficult, but it IS there.

It's not impossible to suck.

[AngelLestat]

1 hour ago, fredinno said:

The pressure differential is very slight, so it will be difficult, but it IS there.

It's not impossible to suck.

kinda it is..  Mercury "atmosphere" is 1x10exp-14 bar   That is much higher vacuum that the one we can achieve with normal vacuum pumps, to go higher than that it would require specialize vacuums machines that are multistage..  

In fact if you accomplish that, the few molecules around that "vacuum zone" will take a long time before realize they can expand a bit more to that place.. 

 

[Nuke]

i think the problem is these particles are coming in at velocity. when you are collecting them you are also collecting their momentum. needless to say station keeping is going to be an issue.

[PB666]

11 hours ago, fredinno said:

Mercury isn't tidally locked, so a collecting station would experience a very long night, making this much less useful.

 

Read this for more details where the valley ice resides. https://en.wikipedia.org/wiki/Mercury_%28planet%29#Surface_conditions_and_exosphere

If you land on a sun exposed surface, there is no water. If you land on the night non-polar there is no water, buy your could land on a sun non exposed at an elevation were you could poke up a heat exchanger, and get heat, and close to the poles this is were plasma that has struck mercury and slowed down.

Start with plasma traveling 250k m/s it will not form water, it strikes mercury's surface and slows down to hundreds of miles per hour (the energy goes into the surface and is radiated back into space), it is still plasma but flux back and  forth into hydrogen, water, other compounds, the flux is from the hot to cold side and from the solar wind facing to gas abating edges. As the gas rolls around the edges the temperature falls from 700K to 100K but around 200K and water and ammonia that has formed begins to sublimate and gravitationally falls into the craters, since these are polar it remains in the craters until the next major asteroid impacts mercury. Likewise any ship will experience perpetual day are night depending on where it lands.

[fredinno]

4 hours ago, PB666 said:

Read this for more details where the valley ice resides. https://en.wikipedia.org/wiki/Mercury_%28planet%29#Surface_conditions_and_exosphere

If you land on a sun exposed surface, there is no water. If you land on the night non-polar there is no water, buy your could land on a sun non exposed at an elevation were you could poke up a heat exchanger, and get heat, and close to the poles this is were plasma that has struck mercury and slowed down.

Start with plasma traveling 250k m/s it will not form water, it strikes mercury's surface and slows down to hundreds of miles per hour (the energy goes into the surface and is radiated back into space), it is still plasma but flux back and  forth into hydrogen, water, other compounds, the flux is from the hot to cold side and from the solar wind facing to gas abating edges. As the gas rolls around the edges the temperature falls from 700K to 100K but around 200K and water and ammonia that has formed begins to sublimate and gravitationally falls into the craters, since these are polar it remains in the craters until the next major asteroid impacts mercury. Likewise any ship will experience perpetual day are night depending on where it lands.

Then a collecting station at mercury is pointless. Just mine the voatiles from the poles.