Hi, Anne:
The missing samples involve material that NASA allocated to somebody
and now the somebody or somebody's heirs can't find the sample.
Many analyses are destructive. If an investigator wants a sample
removed from her or his inventory that was destroyed in analysis,
there's a simple form to fill out. The sample is removed from the
investigator's inventory and recorded as destroyed in the NASA data
base. Those samples would not be counted among the missing. I
suspect that a number of the "missing" samples were, in fact,
destroyed and the paperwork was not submitted.
Most thin sections used by investigators are prepared at NASA JSC (a
fine thin-sectioning lab). So, NASA keeps track of the mass loss
there and that material is not counted among the missing. (In the
data base, I think its called "attrition.")
When an investigator receives a thin section, the nominal mass of
record is always 0.010 g. If you look at the histogram I sent,
there's a big peak at 0.006-0.011. Most of these samples are 0.010-g
thin sections. Thin sections are easy to lose. They count as a line
item, but the mass of record is only 0.010 g. For the reasons you
give, however, they represent a lot more material.
hope this helps,
Randy
At 04:44 PM 2011-12-12 Monday, you wrote:
Thank you Randy for this "accounting".
But it seems to me that other factors are being ignored.
First of all some of your experiments and analysis are necessarily
destructive, and you cannot account for material that has been vaporized, or
dissolved.
Also, some of that material has been cut to make thin-sections, with an
unavoidable cutting and polishing loss.
Yes those losses would be small, but I expect that other the years hundreds
of experiments and thin-sections have been done, all these add up and
probably account for at least some of the missing material.
Anne M. Black
_http://www.impactika.com/_ (http://www.impactika.com/)
_IMPACTIKA@aol.com_ (mailto:impact...@aol.com)
Vice-President, I.M.C.A. Inc.
_http://www.imca.cc/_ (http://www.imca.cc/)
In a message dated 12/12/2011 1:09:43 PM Mountain Standard Time,
koro...@wustl.edu writes:
I'd like to address this issue of missing Apollo samples as a researcher.
I just checked my inventory. I have 999 (really!) line items of
samples from the 6 Apollo and 3 Russian Luna landing sites from
NASA. I can think of only 1 or 2 other researchers who might have
more. The total mass is 320.064 g (0.08% of the collection). That's
an average of 0.32 g/sample. But, even that number is
misleading. The mass distribution looks like this.
http://meteorites.wustl.edu/Korotev_NASA_Apollo_&_Luna_samples.jpg
Only 49 of the samples exceed 1 gram is mass. All of the samples >3
g are not "rocks" but regolith (alias soil or dust) samples. The
smallest samples are all thin sections.
My point is that every article about this issue shows a photo of a
big rock, and NASA just doesn't issue big rocks to us
researchers. As someone else mentioned, I suspect the actual mass of
missing material is not large.
Randy Korotev
______________________________________________
Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html
Meteorite-list mailing list
Meteorite-list@meteoritecentral.com
http://six.pairlist.net/mailman/listinfo/meteorite-list
