New luna images raining on the water parade

[kane007]

<b>Space.com</b> 2006/10/18<br /><br />New high-resolution radar images of the Moon have diminished hopes that the lunar poles might harbor water that could sustain future lunar and solar system explorations.<br /><br />The images, discussed in the Oct. 19 issue of the journal Nature, showed no evidence that ice exists in craters at the lunar south pole.<br /><br />Even in the lunar summer at the south pole, the Sun barely edges above the horizon, so the bottoms of impact craters are in permanent shadow.<br /><br />Since the 1960s, theorists have suggested that these "cold traps" might contain deposits of water ice. The theory was bolstered in 1992 when Earth-based radar telescopes located "ice deposits" inside impact craters at the poles of the planet Mercury.<br /><br />Because of the tilt of the Moon's orbital plane relative to the Earth's equatorial plane, the Earth can rise much higher above the horizon at the lunar south pole than the Sun, so telescopes on the Earth can use radar to "see" some of the shadowed areas of the Moon.<br /><br />Earth-based radar measurements of the Moon since the 1990s have consistently failed to detect ice deposits similar to those on Mercury.<br /><br />Since water ice could be converted to oxygen, drinkable water or even rocket fuel, it would be a valuable resource for any future lunar base. Because of this high value, NASA's 2008 Lunar Reconnaissance Orbiter will crash two vehicles onto the Moon to search for water ice at the South Pole.<br /><br />In 1999, the Lunar Prospector orbiter discovered concentrations of hydrogen at the lunar poles. If this hydrogen were in the form of water molecules—still a subject of debate—then it would correspond to an average of 1 to 2 percent of water ice in the lunar soil in the shadowed terrain.<br /><br />"These new results do not preclude ice being present as small grains in the lunar soil based on the Lunar Prospector's

 

[halman]

kane007,<br /><br />It would be pleasant if water could be found so near at hand as we begin our expansion into the Solar System, but as long as energy is available, and oxygen can be found, we will find a way to create water. Considering that the Lunar regolith consists of about 43 percent oxygen, and that huge amounts of energy are available for about 1/3 of the time, the hardest part will probably be finding hydrogen. Of course, that element is the most abundant in the Cosmos, so there must be some lying around nearby. <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>

 

[mrmorris]

<font color="yellow">"Of course, that element is the most abundant in the Cosmos, so there must be some lying around nearby. "</font><br /><br />Well -- it's the most abundent element in the universe in the form of H2 -- most of which is concentrated in stars. There certainly won't be any H2 lying around the Moon. It would long since have packed its bags and left. S'possible that there's hydrogen tied up in non-volatile molecules, of course, but baking out the hydrogen might not be feasible.<br /><br />However -- luckily, H2 is only 12% (IIRC) of the mass of water. Take along a tank of H2 on lunar forays. Combine with LUNOX by means of a fuel cell (conveniently producing power at the same time) and you've generated home-grown lunar water. Said water will be used and recycled over and over. Assuming efficient recycling processes, the amount of lunar water available will grow steadily.

 

[willpittenger]

The image shown looks more like a visible light image. There are shadows. Also, the craters are not identified. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[Leovinus]

As an aside, I think it's fantastic that they named a crater at the lunar South Pole after Shackleton. <div class="Discussion_UserSignature"> </div>

 

[halman]

mrmorris,<br /><br />I seem to recall reading somewhere here that the solar wind contains hydrogen 3. If that is true, we might be able to collect it somehow. Even if that is not feasible, I believe that something will work out. For one thing, we have not drilled more than a few feet into the lunar surface, so we could easily be overlooking sublunar resources.<br /><br />I remember when I was a kid it was taught in my science textbooks that all oxygen on Earth was the result of plant life, as oxygen was considered fairly rare. Now we know that oxygen is the ash from one of the stellar combustion sequences, and is actually rather common. To discover that hydrogen is locked up in a compound common a few meters below the lunar surface would not be that much of a surprise. <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>

 

[JonClarke]

The radar data can apparently be interpreted in different ways, especially at such low incidence angles.<br /><br />What really needs to be repeated is the neutron spectrometry that first suggested hydrogen was in the shadowed areas. We will have to wait until LRO.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[cuddlyrocket]

According to this abstract, Hydrogen is present in the lunar regolith at about 50 parts per million and Carbon at about 100 ppm. It's apparently possible to extract both these simultaneously to produce methane, which is an acceptable rocket fuel. The process also produces the oxygen to make up the rest of the propellant. And the authors think this process would be economically feasable with improved excavator, extractor, and power technologies.

 

[barrykirk]

Well, we still know that their is plenty of hydrogen in comets and some asteroids and that hydrogen is not buried at the bottom of a gravity well.<br /><br />Asteroids and comets may be energetically easier to reach and return from than the moon.

 

[mrmorris]

<font color="yellow">"...the authors think this process would be economically feasable..."</font><br /><br />Yes -- it's amazing how easy it is to make things feasible with thought exercises. <b>If</b> we had solar cells with 70% efficiency amd <b>if</b> we had equipment that could collect fifty tons of regolith per day and <b>if</b> we had an extraction process that was 92% efficient, then this works like a charm. The full article would mention nothing about *how* to make those improvements -- just that it would be great if they existed.<br /><br />That's not to say that I believe this will never happen. However, even with just the abstract, it's clear they're talking about a process for a fairly distant future. If the abstract were using terminology like 'current' manufacturig techniques, 'off-the-shelf' items, or 'minor improvements to existing processes' -- then this is something that might be a short-term solution. For the forseeable future -- unless there's water ice on the Moon -- we'll have to either ship hydrogen or water from Earth.

 

[mrmorris]

<font color="yellow">"...were not visible to the Radar. "</font><br /><br />The article talks about this. The images were taken when the moon's orbit took it high enough that the south pole could be imaged. From the article:<br /><br /><i>"Because of the tilt of the Moon's orbital plane relative to the Earth's equatorial plane, the Earth can rise much higher above the horizon at the lunar south pole than the Sun, so telescopes on the Earth can use radar to "see" some of the shadowed areas of the Moon. "</i><br /><br />If your empahsis was on <b>most</b> -- that may be the case. The article says 'some' of the shadowed areas were able to be imaged -- I haven't seen anything that gave a percentage (i.e. were they able to image closer to 80% of the shadowed areas or 8% of them).

 

[mrmorris]

<font color="yellow">"I believe you mean helium 3. "</font><br /><br />Correct. There's no such thing as Hydrogen 3. However, I did a quick Google and the solar wind contains both hydrogen (or hydrogen 1 if you prefer <img src="/images/icons/smile.gif" /> ) and helium (2 <i>and</i> 3). <br /><br />Mind you -- whether collecting it is practical is another thing entirely. The oceans of Earth contain vast quantities of dissolved gold -- but running down to the beach with a pair of tweezers isn't going to make you rich. <img src="/images/icons/smile.gif" />

 

[PistolPete]

Quote from the article<br /><blockquote><font class="small">In reply to:</font><hr /><p>"These new results do not preclude ice being present as small grains in the lunar soil based on the Lunar Prospector's discovery of enhanced hydrogen concentrations at the lunar poles," said Donald Campbell, a Cornell University professor of astronomy and a principal investigator of the study. <font color="yellow">"There is always the possibility that concentrated deposits exist in a few of the shadowed locations not visible to radars on Earth, but any current planning for landers or bases at the lunar poles should not count on this."</font>p><hr /></p></blockquote><br />I thought that last little bit was interesting. Any hydrogen, no matter how small, would be worth it's weight in gold if, <i>if</i>, it could be easily extracted.<br /><br />One thing that this does seem to put a damper on is using hydrogen for rocket fuel. If there were large magical deposits of ice on the poles, then, as stated before, the oxygen and hydrogen could be extracted for rocket fuel. If He3 becomes the new oil, then I had the idea (and I'm sure I'm not the only one) to use the oxygen and hydrogen to fuel a lunar based cycler to transport the fuel. If I have done my math correct, then the delta v from the lunar surface to LEO (using aerobraking), back to the lunar surface is about the same as the delta v from the surface of the Earth, to LEO. That's a lot of fuel, but that also means that it is a lot of fuel that doesn't have to be transported on top of a huge, and hugely expensive, expendable launch vehice. I had high hopes for this. Hopefully, some other rocket fuel can be found on the lunar surface (I think someone allready mentioned LOX & liquid methane), otherwise lunar bases may not be economically feasable in the near future (read: the next 50 to 100 years).<br /><br />As a side note, this still doesn't change the fact that future lunar bases will still probobly be at the poles due to <div class="Discussion_UserSignature"> <p> </p><p><em>So, again we are defeated. This victory belongs to the farmers, not us.</em></p><p><strong>-Kambei Shimada from the movie Seven Samurai</strong></p> </div>

 

[mrmorris]

<font color="yellow">"...future lunar bases will still probobly be at the poles due to the constaint sunlight."</font><br /><br />I doubt that's enough of a reason. Polar locations are much harder to reach from a dv perspective, and there are enough engineering concerns to solar panels at the poles to offset the engineering required for a 14 day cycle of solar/stored power. Solar panels at the poles require a much more complex support structure. They must be mounted vertically -- the sun after all is not 'up' but 'across'. The panels either have to rotate 360 degrees, or it's necessary to install solar panels in a ring around the base. Since they'll block sunlight (producing absolute dark behind them) and since the base itself would like to have sunlight -- you'll probably want to mount them on towers above 8' or so in order to allow sunlight to reach the base. It's not a pretty picture. It's certainly worth it to get to the water... but if there is no water to get to, then no.<br /><br />By contrast -- solar cells at a location closer to the equator could be laid horizontally, with little support structure required. They do not need any 'tracking' capability at all. Simply install enough that just after 'dawn' and just before 'sunset', the high-incident sunlight produces enough power to run the base. For the remaining ~12 days when the incident angle is less -- the panels will be producing excess eneregy, which will be captured by charging batteries, electrolyzing water for fuel cell usage, etc. It's a much more straightforward engineering issue.

 

[trailrider]

"These new results do not preclude ice being present as small grains in the lunar soil based on the Lunar Prospector's discovery of enhanced hydrogen concentrations at the lunar poles," said Donald Campbell, a Cornell University professor of astronomy and a principal investigator of the study. "There is always the possibility that concentrated deposits exist in a few of the shadowed locations not visible to radars on Earth, but any current planning for landers or bases at the lunar poles should not count on this." <br /><br />I guess we'll just have to go there and find out for sure!<br /><br />Ad LUNA! Ad Ares! Ad Astra!

 

[cuddlyrocket]

"For the forseeable future -- unless there's water ice on the Moon -- we'll have to either ship hydrogen or water from Earth."<br /><br />I quoted the abstract simply for the concentration figures, and I agree with your scepticism as to whether the 'improvements' involve unobtanium or not.<br /><br />However, I see no reason to doubt their conclusion that extracting methane rather than Hydrogen for rocket fuel is more efficient.<br /><br />I expect Oxygen extraction to be the first ISRU technology (after solar power), and extracting Oxygen from regolith will probably drive off any Hydrogen, so developing the technology to maximise that would be an obvious strategy.<br /><br />And we don't have to aim for 100% lunar-derived Hydrogen initially. Every little will help. But, I agree - for the forseeable future we'll need to supply Hydrogen from Earth. (And supply it as Hydrogen, as water is mainly Oxygen.)

 

[henryhallam]

<font color="yellow"> There's no such thing as Hydrogen 3.</font><br /><br />Well there is, it's called tritium, but I don't think there's a significant amount of it in the solar wind, it wouldn't build up on the moon since it decays with a half-life of 12 years into He3. Besides, you wouldn't want to make it into water and drink it.

 

[mrmorris]

<font color="yellow">"Well there is, it's called tritium..."</font><br /><br />You learn something new... every day. I knew that tritium is produced on Earth by bombarding Lithium with neutrons. Ergo -- if anyone had asked me prior to tday -- I would have said it was an isotope of Lithium rather than one of Hydrogen.

 

[halman]

henryhallam,<br /><br />Wow! I was wrong on BOTH counts! <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>

 

[barrykirk]

Hydrogen 3 is called Tritium and I used to have some in my watch to make it glow.<br /><br />And there is no helium 2

 

[halman]

mrmorris,<br /><br />Perhaps I am alone in holding this perspective, but I feel that the fanfare about water ice on the Moon is vastly overblown. Yes, it would be wonderful if it did indeed exist, but whether or not it is present should not have any impact on our current exploration plans. Either we decide to go to the Moon to find what is there, both on and below the surface, and to learn how to survive in an alien environment, or we base our plans on the possibility that water ice might exist at the lunar poles in sufficient quantities to justify sending our initial exploration teams to those locations.<br /><br />We should not be biased in our approach to exploring this new world, for we could end up missing a far larger bonanza in our search for one of many needed resources. The Lunar maria are tantalizing in that they are basically unique in the Solar System, and merit extensive investigation for mineral resources, as well as clues to the formation of the Earth-Luna system. To discover that there are large quantities of light metals close to the surface of the maria, for instance, would have a substanitial impact not only on our long term plans for exploring the Solar System, but on the level of near-term investment in off-planet development. <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>

 

[barrykirk]

Both Tritium and Deuterium are consumed by solar fusion reactions in the cores of stars. In fact they are consumed much much faster than good old Hydrogen 1.<br /><br />Most of the Deuterium in the universe was created a few minutes after the big bang.<br /><br />As for the tritium, well with a half life of 12 years... Gee, I seemed to remember 22 years, well my memory isn't the same as it used to be.<br /><br />As for the tritium, I'm not sure what the biggest source is. I think that it can be manufactured from lithium in a reactor.

 

[mrmorris]

<font color="yellow">"And there is no helium 2"</font><br /><br />Helium 2 & 3, Helium 3 & 4 -- what's a dropped proton/neutron pair anyway? Today is just not my day for nuclear chemistry.

 

[bitbanger]

Another possibility is to use a LOX aluminum propellant mix. Do a web search for 'LOX-aluminum monopropellant' and see what is possible.<br />

 

[nyarlathotep]

You can also produce it through neutron capture with either Boron-10 or deuterium.