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Re: Moonquakes

Subject: Re: Moonquakes
From: Henry Spencer
Date: Fri, 17 Mar 2006 02:14:48 GMT
Newsgroups: sci.astro, alt.sci.planetary, sci.geo.earthquakes
In article <[email protected]>,
al <[email protected]> wrote:
>J W Freeman and H K Hills Rice Uni. report on the detection of water vapour
>by suprathermal ion detectors left by Apollo 12 and 14.

If that's the Freeman/Hills/Vondrak paper of 1972, note that there is wide
consensus that the water vapor was from LM exhaust gases adsorbed in the
soil, and outgassing from the LM itself.  The gas concentration declines
steadily from one lunar day to the next; the instruments didn't last long
enough for the LM-related contamination to fade to insignificance, which
looks like it would take years. 

The mass spectrometer in the Apollo 17 ALSEP gave more useful data, and
actually yielded some information on the real lunar atmosphere, although
its data too was massively contaminated by LM residuals. 

Current estimate is that there is perhaps one water molecule every few
cubic centimeters in the daytime lunar atmosphere, formed by interactions
between the much-more-common solar-wind hydrogen (3,000-10,000/cc) and
either CO2 (1,000/cc) or oxygen in surface materials. 

(Ref:  Heiken et al, "Lunar Sourcebook".)

>Cambridge S O Agrell J H Scoon found geothite (rust) Fra Mauro.

"...FeOOH has been found and often described as 'rust' in lunar rocks from
every mission, particularly those from Apollo 16...  It has been
conclusively shown that this phase, the mineral akaganeite (beta-FeOOH),
is the product of contamination of the lunar rocks by terrestrial water
vapor, which caused the oxyhydration of indigenous lawrencite, FeCl2, to
form this water-bearing phase (Taylor/Mao/Bell 1973)."  (ibid, p. 150)

>The old stuff is the best.

"The good old days mostly weren't."
-- is temporarily off the air;               |   Henry Spencer
mail to henry at instead.               | [email protected]

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