From: Henry Spencer <henry@zoo.toronto.edu>
Newsgroups: sci.space.science,sci.space.tech
Subject: Re: Did we really go to the moon?
Date: Sun, 30 Jun 1996 19:52:21 GMT

In article <4r548l$ead@crl10.crl.com> gherbert@crl.com (George Herbert) writes:
>>...Given all that I've just said, it would seem that
>>there should be some sort of crater under the LEM once it landed.  At 
>>least the area under the LEM should be blown clear of sand, rocks, dirt, etc.
>
>Look at the films of descending landers, the films of the ground as it
>comes in to land.  You see the dust being kicked up and disturbed.
>The reason you don't see a deeper crater is that the dust more than
>a couple of inches down is very tightly bound together by vaccum
>welding effects...

Actually, vacuum welding is less significant (last I heard) than the
extremely firm packing produced by millennia of meteorite impacts.  The
lunar soil, apart from a very thin surface layer, is packed harder than
can easily be achieved on Earth with heavy machinery.  Look at how hard
the astronauts had to work to get the flag to stand up, because they
couldn't push the pole in very far.

In any case, we have an excellent comparative example:  look at what
happened when DC-X made an emergency landing on the White Sands gypsum
after flight #5 was aborted.  DC-X was considerably heavier than a
landing LM.  It was landing against six times the gravity.  It was
using engines producing hotter and faster exhaust jets than the big,
low-pressure LM engine.  Its engines fired right down to the ground,
rather than being shut down 2m up when contact probes touched.  And
what happened when it landed?  A shallow dimple under each engine, so
hard to spot from any distance that the ground crew marked the spot
with a stake before moving DC-X, so they could find it again!

There is also a small pragmatic issue.  The fake-landings theory is an
"idiot plot", in writer's jargon:  it works only if all the characters are
idiots.  NASA spends many millions of dollars on faking a lunar landing,
but forgets to put a crater under the engine?  Come now, this is silly. 
Nearly everyone *expected* a crater.  The fact that there wasn't one is a
strong hint that the landing *wasn't* faked. 
-- 
If we feared danger, mankind would never           |       Henry Spencer
go to space.                  --Ellison S. Onizuka |   henry@zoo.toronto.edu