From: vince@offshore.ai (Vincent Cate) Newsgroups: sci.space.tech Subject: Re: Radiation shielding for hotel at GEO? References: <9186edb5.0308081641.5036919e@posting.google.com> NNTP-Posting-Host: 207.42.133.230 alexterrell@yahoo.com (Alex Terrell) wrote in message news:... > "Passive shielding is known to work. The Earth's atmosphere supplies > about 10 t/m^2 of mass shielding and is very effective. Only half this > much is needed to bring the dosage level of cosmic rays down to 0.5 > rem/yr. In fact when calculations are made in the context of > particular geometries, it is found that because many of the incident > particles pass through walls at slanting angles a thickness of shield > of 4.5 t/m^2 is sufficient. Thanks! > If using a Rotovator you could base your hotel at L4 / L5. I really like the potential of launching a SSTT (single stage to tether) rocket every 100 minutes that an equatorial LEO rotovator gives me. But the Moon or L4/L5 would only cross an equatorial orbital plane every 2 weeks. So if I were to toss directly from LEO I could not use my rocket or LEO tether as often. So it seems better to accumulate stuff at GEO and then do a few big tosses from there every 2 weeks. The smaller delta-V from GEO means we don't need so much tether mass to handle a big payload. > This may take 1 to 2 days to reach instead of 4 hours, but the orbital > insertion requirement is less. The toss from LEO to L5 is harder than the toss to GEO. Having some delta-v at GEO is not bad as it is a small enough amount that a tether can handle it. I get about 4 days for my tosses to the Moon, and would expect similar to L5 (would guess longer rather than shorter to L5). The shielding for this longer time seems more troublesome. > Overall, I think radiation is a huge problem for fixed elevators and > skyhooks, but a rotovator is much less of a problem. I agree. -- Vince ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Vincent Cate Space Tether Enthusiast vince@offshore.ai http://spacetethers.com/ Anguilla, East Caribbean http://offshore.ai/vince ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ You have to take life as it happens, but you should try to make it happen the way you want to take it. - German Proverb