Thanks for explaining your analysis. I’ll confess to a math error on the 600 million tons of ice but I had nothing to do with the Hg measurements or the interpretation of its presence to begin with — that came from LCROSS and LAMP, neither of which I was involved in.

In fact, the original estimate (arithmetic error aside) had to make some additional assumptions, such as pure ice (it probably isn’t; if I had to guess, I would say it’s probably on the order of ~50% water ice, based on CPR enhancement) and zero ice elsewhere (which we know is definitely not correct; the LCROSS impact area (which contains 5-10 wt.% ice) shows no radar enhancement. If all other areas were so endowed, there would be trillions of tons of water ice there).

I had asked Paul about how the 600 million metric tonnes of the relatively pure ice (that has become a virtual meme within the internet echo chamber) we believe to exist in the anomalous craters of the northern polar region, and he pointed me to slide 24 in the following presentation:

http://spudislunarresources.nss.org/Papers/Spudis_VSE%20mission.pdf

At first when I looked at the spreadsheet, my eyes in typical internet fashion glazed over and simply focused on the bottom line: an estimate of 608,000,000 metric tonnes.

Then about a year later, I revisited it, and something didn’t quite add up this time. So I decided to reverse engineer the spreadsheet, which I was able to do.

First I entered the diameters of the 40 listed anomalous craters into column A. Then I calculated the area (and see that you all used “3.14” rather than the “pi()” function–no big deal). So far so good.

Then I calculated the Volume/Mass of the relatively pure ice (since 1 m^3 of ice is approximately equal to 1 metric tonne, the magnitudes are the same). So there are a million m^2 in one km^2: that gives you the area in m^2. Then multiply by 2 meters to get the volume/mass. Tote them all up, and I got the 608,000,000 metric tonnes–exact same result in the original spreadsheet.

ONLY ONE PROBLEM: the “=___*1,000,000*2” formula references column A–the diameter–rather than column B–the area!

When that is fixed, you get a total mass of 5,834,120,000 mT–about an order of magnitude difference!

Really, it’s not that big of a deal IMHO; it’s an honest mistake; life happens; I myself make such mistakes all the time. Luckily I got my friend Hop to help check my stuff–he’s good at the math.

The good news is that that it turns there’s more like 6 billion tonnes of the relatively pure ice, and since the 2 meter depth is a lower limit, and it could well be the case that the ice could be up to 20 meters deep or more, the true amount is probably somewhere between 6 and 60 billion tonnes.

That raises an interesting scientific question: Are comets and water-bearing asteroid impacts enough to account for this higher number?

The other mistake was in George Reed’s “Don’t Drink the Water” paper first published in 1999. He took a stab at estimating the expected mercury concentration within PSRs. Nothing much happened until the LCROSS/LRO-LAMP results showed that huge Hg spike in the spectrum. Reed’s was duly rediscovered, his original prediction of the Hg concentration was quite close to the LCROSS estimate. Reed’s paper was much praised for “hitting a bullseye” and was repeatedly cited in subsequent papers.

Only one problem: when you redo the math, there was a typo or a confusion of units between cm and m, and the true estimate of the Hg concentration should have been reported as two orders of magnitude lower than the printed result–entailing that the match with the original LCROSS results was much less accurate than first thought.

I since redid a Reedian analysis of the Hg concentration and by changing a few assumptions I was able to obtain a predicted Hg concentration that was again quite close to the LCROSS result. This was published in an AIAA conference proceeding.

Only one problem: my estimate of the area was back calculated from the 600 million m^3, throwing off my own estimate by like a factor of 6!

So you can see how errors get propagated through the literature. But the truth eventually surfaces, and thus science–unlike literary criticism, philosophy, theology–is a truly self-correcting process.

Bottom line: there’s a lot more water up there than we realized! 😉

Since hopdavid “credits” revelations of “glaring math errors ” in that work to a Warren Platts and there is someone posting in this particular series of comments under the name Warren Platts perhaps hopdavid or Mr. Platts could details the errors and where Mr. Platts expose of the “glaring errors” was reviewed and published.

That would be on topic for the original purpose of this article.

Wow. Thanks for explaining that Warren. It all makes sense [sic] now.

Care to elaborate on the nature of these “errors”?

This could get ugly. I hope it does. I want it to get so ugly that the hierarchy of NASA two faced double agents installed to carry out the NewSpace LEO business plan have to resign.

Uh-oh. Never looks good for the future of Human Space Flight when the obvious stranglehold NewSpace and the LEO business plan have on NASA is exposed like this.

A Moon return bypasses LEO and dumps the NewSpace business plan in the trashcan. This is in direct conflict with the reality of the ice on the Moon as the critical enabling resource that should be the focus of the entire Human Space Flight community.

Joe, I scanned some LunOx material and it was very interesting. I have never been happy with my own conclusions about robot landers being necessary and it is encouraging that scientists and engineers proposed a similar scheme. They did not know about the lunar polar ice back then and I believe the ice makes it far more practical. Especially if there are enough of those volatiles which Dr. Spudis has explained several times.

Locked in the lunar ice are presumably volatile elements useful as catalysts in chemical processes. The importance of these trapped volatiles is simply separating this water ice into hydrogen and oxygen and calling it rocket fuel is not the miracle it might seem. Hydrogen is super cold, “boils off”, and recovering and liquefying this loss is a difficult proposition due to exothermic products generated in the process, space radiation, zero gravity effects, and other complications. For vehicles launched from Earth there can be no substitute for hydrogen upper stages. However the technology to store hydrogen for any length of time in space is a challenge. Due to its properties hydrogen presently cannot be available to a spacecraft for more than a few hours after launch.

The percentage of volatiles mixed into lunar polar ice mean common industrial chemical processes can be utilized to produce methane and oxygen using the ice as feed stock. Though giving a lower Isp than hydrogen, storage and handling is greatly simplified. Liquid methane and liquid oxygen are rocket propellants having similar cryogenic characteristics and can be maintained in spacecraft “zero boil-off” systems for longer duration missions where liquid hydrogen is currently impractical. A family of reusable and multi-use methane-oxygen systems would be very useful in establishing a cislunar infrastructure.

I find it extremely interesting that ULA is developing a piston engine for space craft auxiliary power and this type of installation is well-suited for managing methane-oxygen systems. Though they only specify hydrogen in the advert and actually mention refueling (good luck!), as stated, methane is in my view a much better fit and turns this system into “Moon tech.”

The best policy is Richard Feynman’s advice: take *everything* you read with a huge grain of salt. That was well before the current decline in academic standards.