There likely is little or no ice in the Moon’s permanently shadowed craters
The floor of Shackleton Crater showing no obvious ice deposits,
as seen by Shadowcam. The black cross marks the south pole.
Click for original image.
This week the 55th annual Lunar and Planetary Science Conference is being held in Texas. The conference was originally established in connection with the Apollo missions to allow scientists to release their Moon research results. It quickly morphed into an annual event covering research from the entire planetary research community.
I have reviewed the abstracts for this year’s meeting, and culled what I think are the most significant new results from the conference, which I will report on in the next few posts.
We begin however with possibly the most important result from the conference, given by the science team for the ShadowCam instrument on South Korea’s Danuri lunar orbiter. That low-light camera was designed to take high resolution pictures of the permanently-shadowed craters of the Moon, to see if there was any visible or obvious ice hidden there. Though the science team presented a number of papers, the summary paper [pdf] by the instrument’s principal investigator, Mark Robinson of Arizona State University, gave the bottom line:
The data so far is finding very little evidence of water ice in these dark regions.
First, the camera has seen no evidence of the predicted bright patches expected from ice. Second, it has found that the radar signals that some scientists believed indicated the presence of pure ice is instead explained [pdf] by the rough blocky surface terrain photographed by Shadowcam. Third, Shadowcam has found very few land features that correspond to the possible presence of near-surface ice, even at the impact site of the LCROSS mission, where instruments recorded a large detection of water vapor in the ejecta.
The early images from Shadowcam had strongly indicated this result (see the posts here, here, here, and here). The more detailed papers presented this week only underline those initial conclusions. Though there remains some uncertainty in these results and there still might be water ice in the permanently shadowed craters at the lunar poles, if so it is much less than hoped, and possibly not there at all.
That these results are getting little play in the press suggests that no one really wants to hear these facts. The entire space effort of whole nations is presently aimed at reaching this lunar water ice. If it ain’t there, then the political impetus for those missions could easily evaporate. Better to make believe the emperor is wearing clothes than admit he is naked.
I say it shouldn’t matter. If humans want to settle Mars, it is essential we do so on the Moon first, if only to learn how to do it at a location only a few days away. The lack of water is merely another challenge that needs to be overcome in order to learn how to build new planetary settlements on alien worlds.
Above all, refusing to recognize the strong possibility that there is lack of water at the lunar poles is a major mistake. If we know early on that water is not going to be available, it might make sense to rethink the missions themselves, if only to prepare for that lack of water. That no one seems interested in doing this means that a lot of lunar missions are going to be designed poorly. It might even make sense to rethink where those lunar bases should be placed.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
The floor of Shackleton Crater showing no obvious ice deposits,
as seen by Shadowcam. The black cross marks the south pole.
Click for original image.
This week the 55th annual Lunar and Planetary Science Conference is being held in Texas. The conference was originally established in connection with the Apollo missions to allow scientists to release their Moon research results. It quickly morphed into an annual event covering research from the entire planetary research community.
I have reviewed the abstracts for this year’s meeting, and culled what I think are the most significant new results from the conference, which I will report on in the next few posts.
We begin however with possibly the most important result from the conference, given by the science team for the ShadowCam instrument on South Korea’s Danuri lunar orbiter. That low-light camera was designed to take high resolution pictures of the permanently-shadowed craters of the Moon, to see if there was any visible or obvious ice hidden there. Though the science team presented a number of papers, the summary paper [pdf] by the instrument’s principal investigator, Mark Robinson of Arizona State University, gave the bottom line:
The data so far is finding very little evidence of water ice in these dark regions.
First, the camera has seen no evidence of the predicted bright patches expected from ice. Second, it has found that the radar signals that some scientists believed indicated the presence of pure ice is instead explained [pdf] by the rough blocky surface terrain photographed by Shadowcam. Third, Shadowcam has found very few land features that correspond to the possible presence of near-surface ice, even at the impact site of the LCROSS mission, where instruments recorded a large detection of water vapor in the ejecta.
The early images from Shadowcam had strongly indicated this result (see the posts here, here, here, and here). The more detailed papers presented this week only underline those initial conclusions. Though there remains some uncertainty in these results and there still might be water ice in the permanently shadowed craters at the lunar poles, if so it is much less than hoped, and possibly not there at all.
That these results are getting little play in the press suggests that no one really wants to hear these facts. The entire space effort of whole nations is presently aimed at reaching this lunar water ice. If it ain’t there, then the political impetus for those missions could easily evaporate. Better to make believe the emperor is wearing clothes than admit he is naked.
I say it shouldn’t matter. If humans want to settle Mars, it is essential we do so on the Moon first, if only to learn how to do it at a location only a few days away. The lack of water is merely another challenge that needs to be overcome in order to learn how to build new planetary settlements on alien worlds.
Above all, refusing to recognize the strong possibility that there is lack of water at the lunar poles is a major mistake. If we know early on that water is not going to be available, it might make sense to rethink the missions themselves, if only to prepare for that lack of water. That no one seems interested in doing this means that a lot of lunar missions are going to be designed poorly. It might even make sense to rethink where those lunar bases should be placed.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
I’m not quite sure that I agree. The theory, at least as I understand it, is that volatiles that strike the moon in the form of cometary debris or whatever, are destined to evaporate and be boiled away by solar radiation, thst is unless they happen to land in a permenently shadowed crater that would protect them from this fate.
As such, then it seems reasonable to assume that this material will accumulate a just a thin, evenly dostributed layer that itself will be continually pulverized by micrometeorites, so will mix in evenly with the ubiquitous “dust” and “powder” of lunar regolith. And I would not be surprised if this doesn’t leave an obvious geologic signature that is visible from orbit. i.e. We should not expect to see glaciers.
Something has triggered the telltale increase in hydrogen measured when orbiting over these regions, so until we actually land in one and physically inspect and analyze some of the regolith there directly we won’t know for sure. As Bob always says, the uncertainty of science. And as we always said as our motto in my major in college, brute force reigns supreme, meaning we really need to touch this stuff or send way better remote sensors to “Know” for sure.
This post is VERY misleading! Indeed, ShadowCam has not seen exposed patches of ice. However, I think most folks already thought that the ice was very likely disseminated in the regolith. Just this morning there was a presentation on a reanalysis of neutron spectrometer from the LRO LEND instrument and that was showing lower levels of ice present in the PSRs than previous estimates but clearly not zero. There is indeed ice in the PSRs, but likely disseminated and probably not present in the upper few or tens of centimeters.
Didn’t Clementine detect hydrogen at the Lunar poles? Did anyone actually expect exposed sheets of ice? It isn’t going to be like in “For All Mankind”.
Mike Borgelt: I distinctly remember many scientists positing the possibility of glacial patches or even crater floors covered with ice after Lunar Prospector detected a hydrogen signal at the poles in the 1990s. This idea was repeated many times over the next decade or so, though most scientists refrained from overstating things most of the time. This possibility however has been understandably used to push for the entire lunar program, and was often overstated to elected officials and NASA political appointees and managers (who should know better) in order to sell the program.
I readily admit there might be water impregnated in the regolith, but as far as I can see, the data continues to suggest it is less than hoped. The closer we get, the less there appears to be there. I fear when we land we shall find almost none.
I might want humans to explore space, but I will not let my biases blind me to new data.
Bill Farrand: See my comment above.
Robert wrote: “That these results are getting little play in the press suggests that no one really wants to hear these facts. The entire space effort of whole nations is presently aimed at reaching this lunar water ice. If it ain’t there, then the political impetus for those missions could easily evaporate. Better to make believe the emperor is wearing clothes than admit he is naked.”
Although I agree no one wants to hear this, I’m not sure that the conclusion of little or no ice is yet a fact. It was never a fact that there is lots of water ice, or that there is any water ice. It is all based upon assumptions and a detection of hydrogen. Hydrogen was detected at the poles when a Centaur upper stage was intentionally crashed into a lunar polar crater, but the quantity of hydrogen was not measurable. The detection led to the assumption that the hydrogen was locked up in water ice, a reasonable assumption, since oxygen is common and carbon is rare in the lunar environment.
However, I have long been skeptical of the quantity of ice we may find. Perhaps there is enough for drinking water for some lunar settlements or colonies. Perhaps there is enough for centuries of interplanetary rockets. Perhaps the hydrogen was actually hydrocarbons and not water at all.
We still need to look and see what it is and how much there is.
We cannot prove that the emperor is naked. The charlatans may have put him in a flesh-colored body-suit (although, the ladies do seem to be having trouble stifling their giggles).
So far, it seems that SpaceX has not assumed lunar water as a propellant for getting to Mars. It sure would be nice if we didn’t have to take all the propellants for space travel from the surface of the Earth, but there are few serious plans for lunar bases, much less settlements or colonies, and I have yet to hear serious plans for projects that depend upon lunar water.
But for science’s sake, we should still look. With the low success rate of our recent lunar landers, it does not seem to be a bad idea to have several different projects physically look for that water in situ, not remotely deduce its existence or lack thereof from orbit. Results from remote sensing is how we got into this dilemma in the first place.
“I say it shouldn’t matter. If humans want to settle Mars, it is essential we do so on the Moon first, if only to learn how to do it at a location only a few days away.”
Forty years ago that was my argument, too. However, we have since gained a lot of experience with remote bases in the Antarctic and in low Earth orbit, and I no longer think that lunar bases are as necessary for learning how to establish martian bases.
So does this mean (if it turns out to be correct) that the basic premise of Artemis south polar landing is eroded?
Artemis always struck me as unnecessarily complicated. Not to mention the weird concentrated focus on the skin color and genitalia of the crew.
WRT the utility of lunar bases as a prerequisite for attempting large scale efforts on Mars I concur with Bob that this is near necessity, not merely optional. And the reason why is demonstrated clearly by SpaceX in their development methodology that values physical prototyping vs computer simulations because the latter are infinitely simplistic compared to what nature really throws at us.
No, Luna is not a perfect proxy for Mars, but it is ideal to cost effectively and as safely as possible develop the technology to fabricate and maintain dwellings and power infrastructure and REUSABLE launch pads and vehicles and space suits that can endure the extremely harsh environment for mission duration lifetimes and all work in a low G environment we cannot simulate at scale terrestrially, etc., etc., etc. IMHO if we do not master such skills locally first then the initial efforts on Mars will be far less successful and far more dangerous than they need be.
What about ice in the lava tubes? I think there could be a mother lode there.
Robert: We don’t know if there is ice in those lunar lava tubes, though it could be there. No lava tubes however exist at the poles, based on high resolution orbital data. We would need to fly missions to completely different places on the Moon to answer this question.
Right now everyone is putting all their eggs into the basket of the permanently shadowed south pole craters. One wonders if this is a good idea.
LCROSS found water at a concentration of around 5% in the ejecta plume as I recall. From what I hear from my dwindling number of former colleges, NASA is very confidant that there is water at the lunar poles. Finding a large concentration is the current Holey Grail.
In reality, Artemis is not worth it if you are looking at settling the Moon. Artemis is all about justifying Old Space.
Keeps the contractors happy so at least there’s some infrastructure available for the equipment needed.
Robert Zimmerman
March 13, 2024 at 9:09 pm
Robert: We don’t know if there is ice in those lunar lava tubes, though it could be there. No lava tubes however exist at the poles, based on high resolution orbital data. We would need to fly missions to completely different places on the Moon to answer this question.
I don’t think we should settle the poles first. We should settle the equator first. And there are lots of lava tubes there. Some of these are several miles long. If there is just a little bit at the poles, then there could be lots of water in the lava tubes. Could find other things too. Like methane, and dry ice.
The equator is between the Moon’s north pole, and south pole.
Unless you want your base on one of the poles I would not even start looking there.
Just build where you think the safest place would be and go from there.
I would like to see a base inside a stable lava tube but i would use a tunnel boring machine to go even deeper for safety..
Not to discount Robinson’s analysis or the Danuri data, but I think that until we get missions on the surface, like VIPER, dedicated and equipped to characterize the presence of water ice in the likely locations, it is going to be difficult to answer this question with high confidence.
Fortunately, there are a number of missions in this vein, to varying decrees, headed for the Moon over the next several years. We’ll know somewhat more before Artemis 3 astronauts step foot on the regolith.