Re: moon dust info - please help

Jonathan Clarke (
Tue, 03 Nov 1998 19:32:09 +1100

Blaine D. McArthur wrote:

> Quick follow up to my last post, I just looked through the Feb. 1969
> issue of National Geographic. Found some interesting stuff.
> On page 213 there is a photo of Thomas Gold of Cornell University
> trowelling some ordinary, dry powdered cement onto the footpad of a
> Surveyor spacecraft. The caption reads in part:
> "In the long-argued question of the moon's surface composition-whether
> rocky, sandy, or powdery...."
> There was without doubt, serious debate about the nature of the moons
> surface. This can not be denied. Gold,at the time of this article,
> several months before the Apollo landing, was not of the opinion that
> the dust would be a problem.
> There is some mention of the limits of earth bound telescopes; nothing
> smaller than 800 feet across. Thus, the Ranger program, as Glenn
> mentioned in his post. A total of Seven Rangers. Much improved
> resolution, still, NASA engineers were not satisfied. I again quote
> from this article, page 218:
> "The Apollo planners needed more. They needed to actually test the
> surface, to assure that astronauts and spacecraft would not be swallowed
> up, as some people feared, in a deep treacherous seas of dust. Five
> successful Surveyors,...soft-landed on the moon and gave unequivocal
> answers...."
> " each spindly spraddle-leggged craft dropped gingerly to the
> surface, its speed largely negated by retrorocket, its THREE FOOTPAD
> strength of the surface measured as much as 5 to 10 pounds per square
> inch, ample for either astronaut or landing spacecraft." (Emphasis added
> by yours truly)
> The October 1966 issue of National Geographic addresses the Surveyor
> program and its finding. No "Sea of Dust", and NASA planners and
> engineers knew this well before the July '69 landing of men on the
> moon. There were a few dissenters, who still thought ther may be some
> areas where the dust could be much thicker. But just look at those
> famous *pads* on the lunar lander. Do you seriously think that if the
> dust layer on the surface was 30, 50, 100 feet of more, that those pads
> would be of any use at all?
> Page 216-217 contains a photomosaic of the area immediately surrounding
> Surveyor 7 showing trenches dug by its "claw arm" No evidence of a
> "deep, treacherous sea of dust" in this 1968 photo.
> I suspect anything in Life (Was Time around back then????) would
> probably be in the same vein.
> And I would still like to see those old tape of the original TV
> coverage.
> Blaine

Searching my National Geographic's for relevant articles about the moon and the
space program occur highlighted the following issues 1) Feb 58, 2) Feb 59, 3)
Oct 62, 3) March 64, 5) Nov 64, 6) Oct 66, 7) Feb 69, 8) Dec 69, and 9) Sept 73.
I have copies of 3, 4, 5, 7, 8, & 9.

Reference 3) deals with the planned Ranger 4 mission to land a seismometer on the
moon (it failed). No mention of dust, but the art work shows a cratered surface
similar to, but somewhat rockier than,what is actually the case. Reference 4)
discussed progress of forth-coming Apollo missions. Again no mention of dust, but
art work of a rocky cratered surface. The October 66 (ref 5) article is about
Ranger 7 and is by Gene Shoemaker (who I was privileged to meet last year). He
gives a good non technical summary of how he developed his model of the lunar
surface which a gardened regolith and eroded by a micrometeorite rain. Again, no
mention of thick dust. Reference 7) is as good a brief summary of the state of
pre-Apollo 11 knowledge as you are likely to get. Blaine has accurately
summarised it's contents. The Apollo 11 landing is covered by ref 8) and - you
guessed it - no thick dust either. Reference 9 is a post-Apollo summary and there
is no mention about any surprises about the nature of lunar surface. Plenty about
other unexpected things (density distribution, internal structure, and heat flow),
but nothing on regolith.

National Geographic is probably a good indicator of what the informed public would
be reading. The articles I was able to "unearth" ("unmoon"???) show that dust
theory was never portrayed in National Geographic as mainstream. At best it was a
contentious possibility. It would be interesting to see Refs 1, 2, and 6 - 1 & 2
should give pre Apollo program summaries of what was known about the moon and Ref
6 reported the Surveyor 1 mission. Anyone out there got them and wants to
summarise their contents? If this thread is still going on Thursday I will try
the second hand book shops!

Another source of info would be the Time-Life books I devoured as a child. There
was one on the Planets and one on the unversie as I recall. Both pre Apollo.