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A new tether spreadsheet

7 Aug 2015, 19:50 UTC
A new tether spreadsheet
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 A few notes on my old spreadsheetsUp to now, most of my spreadsheets for vertical tethers and elevators have been based on Jerome Pearson's work. The taper ratio I've used is based on equation (10) from Pearson's The orbital tower: a spacecraft launcher using the Earth's rotational energy. A screen capture from Pearson's PDF:Pearson is looking at a very specific vertical tether here, a space elevator whose foot is at earth's surface (r0) and whose balance point is at geosynchronous orbit (rs).But I make some substitutions to make Pearson's equations more general:Substitute r0 with rfoot, the distance of the tether's foot from body center. Substitute rs with rbalance. By rbalance I mean the point on a vertical tether where centrifugal acceleration exactly balances gravity.Substitute g0 with gfoot. By gfoot I mean gravity at tether foot. Pearson sets g0 at 9.8 meters/sec2, earth surface gravity. I set gfoot as G*(mass of central body) /  rfoot 2.My resulting spreadsheets were cumbersome and complicated. I don't like complicated -- more opportunities for error. And indeed my early versions had many errors that gave obviously wrong results. Through careful proofreading and many bottles of aspirin I started to get numbers that matched Pearson's. But I ...

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