About the ring being that low -- could it be some sort of "booster" to send
stuff up the next part of the trip? Or possibly local maintenance for part of
the elevator, or there might be some sort of relay substation for sending power
down from orbit. It could also be mostly tourist given that it looked to have
lots of shops, although if anything, I'd expect a "tourist block" to be higher.
Do we have any estimates on how long it takes to get to the Geostationary
Orbit station? Even if it takes the train a while to get there, I'd expect the
better view to compensate for the trip, from a tourist perspective.
As for needing another station past geostationary orbit, yes. Basically an
orbital elevator is balanced with its center of gravity at geostationary orbit.
Just how large of a station you need is based on how far out it is -- one
could also simply extend the tether out an equal distance into space, rather
than having a counterweight station out there. Needless to say, that big
habitat ring probably means you have to extend the tether farther or build a
bigger counterweight. That's a thought: maybe the tether and counterweight
station extend VERY far into space for use in launching lunar or interplanetary
flights, and the habitat ring is there partly to move the center of gravity
back towards Earth? The basic diagrams we saw of the elevator in the video
Saji was watching don't suggest that, but if that wasn't what they were
illustrating, who knows how accurate that part was.
Zone of the Enders: Dolores, i had another good orbital elevator. They used
large asteroids as the starting point for their stations, with the one at the
far end of the tether being configured as a spaceport to take advantage of the
centrifugal force for ships departing Earth. They also had another interesting
feature -- heavy movable counterweights that started near the center station
and moved outwards to compensate for changes in mass at the spaceport end.
> Date: Fri, 9 Nov 2007 16:53:39 -0500> From: [EMAIL PROTECTED]> To:
> [email protected]> Subject: Re: [gundam] Episode 5 Spoilers!> > > > probably
> calculate how fast they were decelerating if we knew the altitude> > > of the
> gravity block.> > Indeed the equation is pretty simple. But honestly I don't
> feel like> > working it out now, it's getting a little too technical for the
> list.> > Ok can't stop myself :P> E^2 ( 1 - r^3/S^3)> a = g ---------
> ------------------------> r^2 ( 1 - E^3/S^3)> > Where a is the gravitational
> acceleration anywhere along the space> elevator at a distance r from center
> of Earth. Remember altitude = (r> - E)> > g = gravitational acceleration on
> Earth surface, = 9.8 m/s^2> S = radius of geostationary orbit = ~42,000,000
> m> E = radius of Earth = ~ 6,300,000 m> > So for r = E, a = g, the normal
> gravity on Earth surface.> For r = S, a = 0, zero gravity> For r > S, a < 0,
> meaning you "fall" away from Earth> > Hope the list doesn't mind a small GIF.
> It's a graph of gravity pull> as percent of normal gravity versus altitude,
> along the space> elevator. At zero altitude, gravity is 100%, at 35,700 km,
> it's zero.> > > BTW, a minor point I didn't cover yet: you do fall straight
> down> (below geosyn. altitude) or straight up (above geosyn altitude).> > If
> my eyes were not too mistaken, Louise was falling at about 0.1g> (see 10% on
> the graph). That means the lower ring's altitude was> under 12,750 km, almost
> 23,000 km below Geostationary orbit. That's> only 36% of the distance from
> Earth surface to Geostationary orbit.> Frankly even I am shocked how low that
> is.> > Ok let's say my eyes were deceived, and she was only falling at 0.02g>
> (see 2% on the graph). Then the lower ring's altitude was under 26,400> km,
> still more than 9300 km below the geosyn orbit. At this altitude> it takes
> more than 3.9 seconds to fall 1.5m. Even if Louise were very> short, she has
> almost 4 seconds after she steps off the 'cliff', to> reach out a hand and
> grab on to the edge. I seem to remember the> scene from when Louise fell off
> to the time when Saji fell below the> edge to last less than one second. Even
> then... we are still talking> about using over 9000 km of tethers to hold the
> lower ring up.> > >From 26,400 km altitude, after 14 minutes (going to the
> gravity block> scene), the block would fall by almost 70 km and attain an
> extra> velocity of almost 600 km/hr. Meaning in 14 minutes it's altitude>
> fell from 26,400 km to 26,330 km, and it's original velocity of over> 8500
> km/hr suffered a maximal 7% perturbation. By comparison, ISS's> altitude is
> under 350 km. Hardly a crisis situation.> > Ok, go back to 12,750km altitude
> scenario (0.1g). After 14 minutes,> the gravity block would have fell over
> 345 km and acquired an extra> velocity of about 3000 km/hr. So it's altitude
> is still over 12,400> km, but its velocity is now an uncomfortably slow 5830
> km/hr. But the> velocity problem has much more to do with the ridiculous
> dangerous> position they started off with, not from 14 minutes of free-fall.>
> Nevertheless, they probably still have an hour of free-falling before>
> reaching the top of the atmosphere (120 km).> > Either way, the amount of
> tether material need to hold up the lower> ring runs in the ridiculous range,
> more than 1 tons of tether per 375> tons of lower ring mass (for high
> altitude case, for the low altitude> case, it is many many times more). And
> the time limit of a rescue is> nowhere near 7-14 minutes, but would in the
> range of one to many> hours.> > > -- > Dr. Core
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