Hydrogen to the Moon

(Inquiring minds) wrote in message . com...
"Alan Erskine" wrote in message . au...
There's gobs of O2 on the Moon (~40% by mass of the Moon's surface is
oxygen), but hydrogen is still needed to make water (remember, the poles are
a long way from an economical-to-get-to equatorial Lunar base, so Lunar ice
may not be a viable option in the short term) and also needed for rocket
propellant.

What is the best way of getting hydrogen to the Moon? Liquid H? Methane?
Both of these are cryogenic and difficult to store for any length of time,
especially LH2. What about hydrogen peroxide or even ammonia? Ammonia
solves two problems as it would provide hydrogen for water and propellant
and also provides nitrogen for crew breathing. Ammonia is both _fairly_
stable and dense when compared to either methane or hydrogen and can be
stored in simple plastic tanks (protected from the Sun's heat).

What are the methods of separating ammonia into its constituent gases?

As an alternative.

Would polyethylene do the trick. It seems to have high hydrogen
content, is a easy to handle solid and when burnt will also release
some carbon, I guess in the form of CO2. It should have good radiation
protection properties as well, although that is a guess.

Now that the Chinese are talking about going to the moon, no doubt
they'll use low cost plastic spaceships which can be disassociated
once they've landed on the moon and failed to take off.

Henry Spencer wrote:

In article ,
Inquiring minds wrote:
Would polyethylene do the trick. It seems to have high hydrogen
content, is a easy to handle solid and when burnt will also release
some carbon, I guess in the form of CO2.

If you want a durable solid rather than a liquid, it's probably about the
best. The hydrogen content isn't as high as propane or ammonia, but it's
not bad.


One advantage of a durable material like this is that it tolerates
hard landings quite well. The reduction in landing propellants by
cutting the sacks of plastic pellets loose at 1000m or more might
make back the difference.

(Inquiring minds) writes:

"Alan Erskine" wrote in message . au...
There's gobs of O2 on the Moon (~40% by mass of the Moon's surface is
oxygen), but hydrogen is still needed to make water (remember, the poles are
a long way from an economical-to-get-to equatorial Lunar base, so Lunar ice
may not be a viable option in the short term) and also needed for rocket
propellant.

What is the best way of getting hydrogen to the Moon? Liquid H? Methane?
Both of these are cryogenic and difficult to store for any length of time,
especially LH2. What about hydrogen peroxide or even ammonia? Ammonia
solves two problems as it would provide hydrogen for water and propellant
and also provides nitrogen for crew breathing. Ammonia is both _fairly_
stable and dense when compared to either methane or hydrogen and can be
stored in simple plastic tanks (protected from the Sun's heat).

What are the methods of separating ammonia into its constituent gases?

As an alternative.

Would polyethylene do the trick. It seems to have high hydrogen
content, is a easy to handle solid and when burnt will also release
some carbon, I guess in the form of CO2.

Presuming you have an excess of oxygen with which to burn it, yes.
And polyethylene is probably the best choice as a solid hydrogenous
compound, which is why it sees use in various nuclear applications
that call for maximum H (or low-Z generally) content in a solid
package.

But if your goal is to ship hydrogen to the Moon, it's a pretty safe
bet that the best way to do it is to ship hydrogen to the moon. The
most conservative design for a hydrogen tank suitable for the trip,
even accounting for LH2's low density and cryogenic nature, is going
to be enormously lighter than the lightest batch of atoms suitable
for binding H into a more tractable form. The best case for that
latter strategy is that you get 25% hydrogen and 75% other stuff,
which ratio will be approximately *reversed* for a simple tank of
LH2.

And yes, most launchers have payload fairings that will hold even
so fluffy a cargo as a full weight load of LH2.


Now, if you specifically *want* a little hydrogen and a lot of
carbon/nitrogen/whatever on the Moon, you may find it worthwhile
to ship methane/ammonia/whatever. But if it's hydrogen that is
your bottleneck, you ship LH2.


--
*John Schilling * "Anything worth doing, *
*Member:AIAA,NRA,ACLU,SAS,LP * is worth doing for money" *
*Chief Scientist & General Partner * -13th Rule of Acquisition *
*White Elephant Research, LLC * "There is no substitute *
* for success" *
*661-951-9107 or 661-275-6795 * -58th Rule of Acquisition *

In article ,
Alan Erskine wrote:
...Ammonia is used as a nitrogenous fertiliser so it releases
nitrogen, but over a long period.

Actually, the whole point of nitrogenous fertilizer is that it *doesn't*
release nitrogen. There's lots of nitrogen around, in the air. What most
plants need is nitrogen *compounds*, because they're not capable of making
their own from nitrogen gas. Ideally you want nitrates, but ammonia is
close enough for a lot of plants.

Ammonia was also used as (from memory)
propellant for the X-15 (?), so what were the combustion products created?

Correct, the definitive X-15 engine burned LOX/ammonia. Combustion
products were mainly nitrogen and water.
--
MOST launched 30 June; first light, 29 July; 5arcsec | Henry Spencer
pointing, 10 Sept; first science, early Oct; all well. |

On Tue, 25 Nov 2003 00:43:06 GMT, Eric Pederson
d wrote:

One advantage of a durable material like this is that it tolerates
hard landings quite well. The reduction in landing propellants by
cutting the sacks of plastic pellets loose at 1000m or more might
make back the difference.

....And it provides your own pre-landing celebratory confetti! Almost
as good as the ticker-tape parade you'll probably get on your return
home :-)

OM

--

"No ******* ever won a war by dying for | http://www.io.com/~o_m
his country. He won it by making the other | Sergeant-At-Arms
poor dumb ******* die for his country." | Human O-Ring Society

- General George S. Patton, Jr

Alan Erskine wrote

Remember, it's got to be easy to 'get at' too. Electrolosys or similar
would be best. Ammonia is used as a nitrogenous fertiliser so it releases
nitrogen, but over a long period.

In the conditions found in soil ammonia (or rather ammonium salts, ammonia
itself would just evaporate) slowly reacts with oxygen in the air to form
nitrates, which is what plants and so on like.

If you put too much nitrate on soil it washes away before the plants get a
change to absorb it, as nitrates are usually very soluble in water. That's
why "ammoniacal nitrogen" is considered a slower-release nitrogenous
fertiliser than "nitrate nitrogen".

Nitrogen is also needed on the Moon for atmosphere, so I thought using
something like ammonia would work (hydrogen _and_ ammonia), but...

If it's to make water with Lunar O2, and some N2 is also needed, then just
burn ammonia in the Lunar oxygen. If you do it right you'd get nitrogen, and
water, and unburnt oxygen, and you could breathe the gas you made once it
was cooled. No need to dissociate it into hydrogen and nitrogen first.

You would also get small quantities of oxides of nitrogen, the amount
depending on the precise conditions. You should probably purify the product
gas to get rid of them. Or, you could tailor the burning conditions to give
a higher yield, and use them to make nitric acid, for explosives, perhaps?

Why else might you want H2 on the Moon? For rocket fuel? But getting it from
earth is far too expensive, you'd be better off using almost anything else
that was locally available once you have the production capacity - eg Lunar
Al dust and Lunar LOX would probably be OK as a propellant.

John Schilling wrote

But if it's hydrogen that is your bottleneck, you ship LH2.

Yes. Most sensible reply so far.

Is there any lack of nitrogen or carbon on the Moon?


--
Peter Fairbrother

Alan Erskine wrote

Remember, it's got to be easy to 'get at' too. Electrolosys or similar
would be best. Ammonia is used as a nitrogenous fertiliser so it releases
nitrogen, but over a long period.

In the conditions found in soil ammonia (or rather ammonium salts, ammonia
itself would just evaporate) slowly reacts with oxygen in the air to form
nitrates, which is what plants and so on like.

If you put too much nitrate on soil it washes away before the plants get a
change to absorb it, as nitrates are usually very soluble in water. That's
why "ammoniacal nitrogen" is considered a slower-release nitrogenous
fertiliser than "nitrate nitrogen".

Nitrogen is also needed on the Moon for atmosphere, so I thought using
something like ammonia would work (hydrogen _and_ ammonia), but...

If it's to make water with Lunar O2, and some N2 is also needed, then just
burn ammonia in the Lunar oxygen. If you do it right you'd get nitrogen, and
water, and unburnt oxygen, and you could breathe the gas you made once it
was cooled. No need to dissociate it into hydrogen and nitrogen first.

You would also get small quantities of oxides of nitrogen, the amount
depending on the precise conditions. You should probably purify the product
gas to get rid of them. Or, you could tailor the burning conditions to give
a higher yield, and use them to make nitric acid, for explosives, perhaps?

Why else might you want H2 on the Moon? For rocket fuel? But getting it from
earth is far too expensive, you'd be better off using almost anything else
that was locally available once you have the production capacity - eg Lunar
Al dust and Lunar LOX would probably be OK as a propellant.

John Schilling wrote

But if it's hydrogen that is your bottleneck, you ship LH2.

Yes. Most sensible reply so far.

Is there any lack of nitrogen or carbon on the Moon?


--
Peter Fairbrother

In article ,
Peter Fairbrother wrote:
Is there any lack of nitrogen or carbon on the Moon?

Unfortunately, yes. The Moon is depleted in essentially anything which
either is volatile (nitrogen), or combines readily with oxygen to form
volatile compounds (carbon).

If the polar hydrogen deposits are in fact frozen volatiles from comet
impacts, there's likely to be ammonia as well as water. It's just
possible that there might be small amounts of hydrocarbons too.
--
MOST launched 30 June; first light, 29 July; 5arcsec | Henry Spencer
pointing, 10 Sept; first science, early Oct; all well. |

In article ,
Peter Fairbrother wrote:
Is there any lack of nitrogen or carbon on the Moon?

Unfortunately, yes. The Moon is depleted in essentially anything which
either is volatile (nitrogen), or combines readily with oxygen to form
volatile compounds (carbon).

If the polar hydrogen deposits are in fact frozen volatiles from comet
impacts, there's likely to be ammonia as well as water. It's just
possible that there might be small amounts of hydrocarbons too.
--
MOST launched 30 June; first light, 29 July; 5arcsec | Henry Spencer
pointing, 10 Sept; first science, early Oct; all well. |

Peter Fairbrother wrote:

In the conditions found in soil ammonia (or rather ammonium salts, ammonia
itself would just evaporate) slowly reacts with oxygen in the air to form
nitrates, which is what plants and so on like.

Actually, plants can absorb ammonium ions as well. And the conversion
of ammonia to nitrate is done by nitrifying bacteria, not direct reaction
with atmospheric oxygen.

If you put too much nitrate on soil it washes away before the plants get a
change to absorb it, as nitrates are usually very soluble in water. That's
why "ammoniacal nitrogen" is considered a slower-release nitrogenous
fertiliser than "nitrate nitrogen".

Ammonium salts are also very soluble in water, so that's not the cause
of nitrate loss. The real cause is that clay, a significant component
of soil, has negatively charged surfaces. This tends to bind positive
ions.

Nitrate is also lost to denitrifying bacteria, which use it to oxidize
organic matter.

Paul