LUNAR EXPEDITION PLAN

4.2.6.6
NASA intends to measure the lunar composition directly
by means of Its Surveyor lunar probe now scheduled for Bid I963.
4.2.8.7
Neither Air Force measurements of overall lunar composition;
nor NASA measurements of spot compositions will satisfy the
requirement for location of lunar resources. Una NASA Prospector
vehicle scheduled for 1966 will obtain store widespread data,
but vti&t Is urgently needed is detailed knowledge of the variation
of lunar composition over the whole surface. Ohis can
only be accompli shed by & lunar orbiting vehicle with appropriate
instrumentation. NASA presently has this planned for 1965 and
the appropriateness of their Instrumentation remains in doubt.
Also this is too late to meet the requirements of the LUHEX
program.
4.2.8.8
2he Importance of lunar subsurface structure in exploration
of the moon lies largely In a possible collapse hazard under
vehicles and personnel, and in the possibility of utilizing -
subsurface structures as shelters and storage facilities.
Present knowledge of lunar subsurface structure 1B based
on a theoretical extrapolation from the presumed origin of the
surface features. The majority of lunar geologists believe that
lunar craters vere formed by means of the impact of large meteorites,
and that only limited volcanlsm has occurred in the lunar
highlands. 3he maria, en the other hand, are thought to be giant
lava pools; although the melting is assumed to have been triggered
by asteroldal impact.
Based on these theories of origin for the lunar surface
features, it is thought that the subsurface structure of the lunar
highlands will consist largely Of overlapping layers of debris
ejected from the impact craters. One collapse hazard of such
material is negligible. 3he maria should be covered by no more
than kO feet of vesicular (bubble filled) lava, -with "«^"i""
vesicle (bubble) size about six feet in diameter. Such terrain
could present a collapse hazard, the severity of which will
depend- upon-actual ^rather than maximum) vesicle size.
It should be noted, however, that a rival theory for the
origin of lunar craters holds that they were produced by volcanlsm
as calderas. Should this theory be correct, the collapse hazard
in the highlands would probably exceed that on the maria.
TOLAS-S-458
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