[net.space] elevators

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