piner@CSvax:Pucc-H:pur-phy.UUCP (09/28/83)
There is a practical problem with elevators too. If your elevator moves at 100 miles per hour. It will take 10 days to reach orbit. Rich Piner Purdue Physics Dept.
mcewan@uiucdcs.UUCP (mcewan ) (10/06/83)
#R:pur-phy:-102900:uiucdcs:12700039:000:347 uiucdcs!mcewan Oct 5 15:20:00 1983 /***** uiucdcs:net.space / pur-phy!piner / 2:03 pm Sep 28, 1983 */ There is a practical problem with elevators too. If your elevator moves at 100 miles per hour. It will take 10 days to reach orbit. Rich Piner Purdue Physics Dept. /* ---------- */ You could say the same thing about the shuttle! Scott McEwan uiucdcs!mcewan
henry@utzoo.UUCP (Henry Spencer) (10/07/83)
Unfortunately, starting from 200 miles up helps you very little when it comes to achieving orbit. It helps some, but most of the fuel burned by, say, a Shuttle, goes into velocity rather than height. 17000 mph takes a lot of rocket. You definitely want to take the elevator all the way up to Clarke ("geostationary") orbit, so that you are at orbital velocity when you let go. As for the time taken, nobody in his right mind has suggested that the elevators move as slowly as 100 mph. Clarke had his "production" elevator cars highly supersonic even while still within the atmosphere. Given enough power to drive it, a 1000-mph elevator should be straightforward with only minimal upgrades to current technology. (The Space Studies Institute's prototype mass drivers have already demonstrated electromagnetic propulsion at far higher accelerations than a passenger system would ever need -- and the latest one is self-centering, so no guide rails or suspension systems are needed.) -- Henry Spencer @ U of Toronto Zoology {allegra,ihnp4,linus,decvax}!utzoo!henry
REM@MIT-MC@sri-unix.UUCP (10/09/83)
From: Robert Elton Maas <REM @ MIT-MC> Let's see, 100 miles/hour, 10 days, 24 hours/day, that's 24,000 miles above the surface. Yeah, if you're going to geosync orbit it'll take that long. I guess people in a hurry had better go 200 miles up (that's 2 hours of travel) then jump off and fire a small rocket to achieve low-Earth-orbit before reaching the atmosphere, then at leisure maneuver to desired orbit. This is a lot cheaper than going all the way from Earth's surface using rockets. Alternately, once you're out of the atmosphere you can go faster than 100 mi/hr, i.e. the elevator can be in two parts, a slow part for initial ascent, then a mass-driver or whatever for fast main part.
crm@duke.UUCP (11/09/83)
The material needed is *REALLLY* strong wire cable, and there is no trouble with the tower falling -- it would actually be under some TENSION, and the problem would be holding it down! Charlie Martin ...!duke!crm