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xkcd #2908: Moon Armor Index
(imgs.xkcd.com)
Alt text:
Astronomers are a little unsure of the applicability of this index, but NASA's Planetary Protection Officer is all in favor.
Yeah, but from surface to space it's ruthly 100 km, so 43 km is quite the cover. Then again, I get what you are saying. I gues it's a matter of perspective.