From: vince@offshore.ai (Vincent Cate) Newsgroups: sci.space.policy Subject: Re: Settle the moon first using tethers References: <9186edb5.0404210736.308d9697@posting.google.com> <9186edb5.0405061618.147d85b4@posting.google.com> <9186edb5.0405072323.2370bb04@posting.google.com> NNTP-Posting-Host: 207.42.133.252 Message-ID: <9186edb5.0405102242.4f04849@posting.google.com> vince@offshore.ai (Vincent Cate) wrote in message news:<9186edb5.0405072323.2370bb04@posting.google.com>... > If we make solar cells from lunar materials I think they can easily cost > several times less than ones in orbit. So making a power grid on the moon > could cost less even if you have several times as many solar cells. On further reflection, I don't expect solar cells in orbit to be so much more costly than solar cells on the moon. On Earth cheaper Solar cells are on the order of $100/lb (say $4/watt and 25 watts/lb). After tethers are operating around the moon, I expect the cost to send stuff from the moon to space will be much less than $100/lb, and solar cells on the moon to cost more than on Earth. So the question is, for 10 million people, is it cheaper/easier to build power lines half way around the moon (about 3,400 miles) and have 2 sets of solar cells than to lift the materials needed to build and shield an orbiting station? In 1/6 G with no wind, ice, etc, you could have power line towers really far apart. You would be using local steel/aluminum for towers and wires. You can set up some mass production. No need for paint. The power lines don't seem so bad. On the other hand, solar cells may be the main cost. Having to have double could really hurt. And it would be more than double if the orbiting guys could use direct sunlight for growing plants. So what was the total mass in the Island-3 design? -- 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