OK, a geosynchronous orbit has a period of 24 hours and returns to the same point above the Earth once a day. You can't leave a space elevator attached to an asteroid in geosynchronous orbit because the asteroid would move North and South in relative position and tear your space elevator to pieces. A geostationary orbit maintains the same relative position to the planet, but is also only available at the Equator. New York is not now and never has been at the Equator.

So an asteroid at the top of a space elevator wouldn't be holding it up, it would be being held in place by the cable.

Discuss.

-Frank

Erk? They put a space elevator down in New York?

I always heard that a space elevator would /have/ to be on the equator and would have to be able to oscillate so as to avoid things in space... like the moon.

Isn't the space elevator in equatorial africa? 2 degrees off I think.

Nope, that African installation would be the maglev space catapult ...

Poor elevator. Poor New York too. I imagine that pull from the cable will cause some tremors.

However, this is why the cunning folks at NASA would want their elevator's earth end to be on a floating platform on the equator in international waters. If you choose to adapt NASA plans, best stick to them, for they ae cunning and well thought out.

The distance a geostationary satelite has to the surface changes quite a bit, depending on the relative position of other celestial objects and the earth's wobble. Thus you'd have to construct your elevator in a way to allow for that.
Also natural geostationary objects don't exist as there are quite alot of factors that can throw you of the orbit and additionaly the possibility of a planet to catch an asteroid into a geostationary orbit is close to nil.
Ignoring this your elevator would have to support itself as, as you mentioned yourself it can't be held up by your satelite. Also it would have to be extremely rigid as to withstand the forces of the wind the shaft will experience. Even if the wind would only move it by a millimeter in the atmosphere you'll end up swinging about 70m on your satelite. Thus you'd need some kind of thrusters to allow it to float at the same position on your satelite, connecting it would most likely push the satelite off the orbit and/or break the shaft.

Crashing into the moon wouldn't be a problem though as the lunar orbit is about 10 times as far away then the geostationary orbit.

Here for all to read
space elevator Wiki

WMS

@suppenhuhn: My bust, I just remember a line from "Red Mars" that talked about how the beanstalk was so long that they had to oscillate it to avoid the moon. Evidently that isn't a problem for an Earth space elevator.

Shadowrun has a Space Elevator?

????

my sentiments exactly . . what the frag ? O.o

Frank, You mention New York? DOe sthis have something to do with the upcoming SRM NYC arc? Or is there some RL news blurb we're missing here?

So New York's not on the equator, heh? Means someone has to hire Shadowrunners to alter the Earth's axis

All quite true.


Well, it was once... in the Devonian era. [/snarky geology student]

Incorrect. The counterweight (the asteriod in your example) is "holding up" the cable by offering a stable location in a stable orbit (geostationary orbit) that the cable can "hang down" from. If the cable was "holding" the counterweight in place as you suggest, geostationary orbit wouldn't be needed.

It's a bit tricky to explain without delving into orbital mechanics, but, basically, the object in geostationary doesn't care if there is a cable attached to it or not; it will continue to orbit above that location on the equator until some other force comes into play. So what is done then is to drop a tether down from geosync; gravity will take hold of it and keep it taut, and due to the fact that it's anchored to something in geosync (something with enough mass and inertia to avoid being "pulled down" by the tether) allows it to basically be lowered all the way down past Low Earth Orbit and down to the ground.

That's a very rough description of the mechanics, and there a dozen other factors I could have metioned, but all of that is the very basic description of an orbitial elevator.



Seconding the question.

isn't there the problem with elevators only being able to go that high because the weight of the cable itself will be too much to be held by the cable itself? not to mention having to add a cabin and enough carry-capacity to make the idea economically viable?

Yup. The only substance that we know of that's capable of taking the strain of supporting its own weight with enough strength left over to support cargo and/or passengers is carbon nanotubules--basically pure diamond threads.

Dikote-chains O.o
else: MAGIC!

In the interest of healthy speculation, here's an FYI to bring you up to speed:

Fact: A space elevator project is underway in the Sixth World (if you missed it check Runner Havens again).
Fact: Two possible areas have been suggested as likely for the terminus - neither is remotely near NYC. (Runner Havens, again)
Fact: Several companies are retasking factories to produce buckytubes/carbon nanotubules (you guessed it, Runner Havens, but also Corporate Enclaves)
Fact: A near-earth orbit asteroid is already being moved into local orbit by a Triple A consortium. (in Emergence).

Why hasn't everyone been paying more attention to this macro engineering project? Good question. Now: discuss.

when will we see the SHADOWRUN IN SPACE Core/Source/Rules-Book?
one book that deals with all the space thingies at once . . all space stations in whatever orbits, all the moon stations, and the mars stations AND this new asteroid thingie too <.< . .
rules for decompression, rules for magic in space, rules for movement and the such . . and of course, tons of fluff
how to get up/down there including the elevator . . maybe an escalator too? and rocket-ships and space-shuttles? or semi ballistic aeroplanes that go out of the athmosphere?

Ah ha! Okay, that makes a bit more sense...
(I don't have any of those books. )

It would appear after a quick glance at Runner Havens that it is an Aztechnology project underway in Panama.....

The traditional beanstalk design can't be in New York. There could be a space fountain. A periodic tether hook could also work, though New York might be only one stop for that.

I don't know where Frank's New-York thing comes from, Synner just said nobody ever talked about New-York.. so wtf?

maybe he'S talking about NY to change the fact that nobody talks about NY?
NY Rule Nr.1: you do NOT talk about NY!

You can't put a counterweight into geostationary orbit. The moment you apply any external force towards the earth on it (like attaching a 35000km long cable) the object will start to sink and then crash onto earth as you just pulled it closer. If you want to use a counterweight it needs to be further away from the earth then that orbit so that you end up with the center of gravity of the system counterweight+tethers+climbers+payload being at a geostationary orbit or better yet a bit beyond it.

Also such an elevator isn't feasible in the least. All it does provide is a cable where your climbers can climb up on, it doesn't provide power supply or anything else. Also a single cable could only support about 20 tons of payload, maybe a bit less and thats for climber+cargo. It also wouldnt be that fast that you could have dozens of tours a day. You're way better off catapulting your cargo into space, then you also don't need to worry about how to store the energy to get there and stuff like that in addition to not have to build that thingie in the first place and maintain it later.

There isn't ACTUALLY a requirement for the end of the tether to be at the equator, but if it isn't, you end up with some 'interesting' static structures and lose quite a bit a of lift capacity... AFAICR, you get about 50% capacity a bit north of New Orleans.

Found the slides (the old links were dead).

Geosynchronous Orbit is a point between the earth and moon... the station doesn't have to dodge the moon.

Ummm I distinctly recall reading bits of rules covering a lot of that already. Didn't Emergence cover at least some of that to a degree?

Iirc it doesn't. It's a story book mainly.

If it's 4th ed, it's mostly Arsenal.
If it's 3rd ed it's Target : Wastelands.

That's right... Extreme environments section of Arsenal covers decompression and the physics of space for SR4...

I think Street Magic (?) had rules on the different magical background counts with a sample of a dwarf on the moon?

Is the point not to use counterweighting to essentially get 'free' orbital transfers? You need to have as much material coming down the well as up and there's friction to pay for but otherwise TANSTAAFL, not.

Unlike the catapult which uses gigantic amounts of energy with every shot.

yeah, there was SOME of that Stuff in Wastelands and Arsenal . . but ALL of that in one single book would be pretty sweet . .
at least saying: "it's shadowrun . . IN SPAACEE!" is cool in it's very own way <.<

God, I hate the stuff in Arsenal. Just reading it made my eyes bleed.

Fixed energy production is really really really cheap compared to the construction of a space elevator. Most climber designs I've seen rely on projected ground power, and really, a tether climber needs just as much total energy as a catapult, it just needs it over a longer time period and avoids the stressful acceleration of a catapult as well as losing less energy to atmospheric friction. If you really want some fun, take a look at the Launch Loop, doesn't require quite the same level of material advancement as a tether, on the other hand, it's a multi thousand kilometer dynamic structure moving at 14km/s that can vaporize itself if it deviates more than a few millimeters from it's stable condition.

Anyways, the point of the counterweight is to not have to have the tether extend too far past geostationary altitude and thus save on construction costs (while significantly reducing vulnerable cross section). The tether is held in tension, by the counterweight (that is moving at greater than orbital velocity for it's altitude), the weight of the portion of the tether that is below geo stationary altitude and the actual base station of the tether, providing an anchor and allowing enough margin for things to actually climb the tether. In the event of a failure, the portion of the tether below the break falls and the portion above the break (along with the counterweight) enters an eliptical orbit with it's low point a little above geostationary orbit.

Sorry, I failed to be clear and precise.

By counterweighting I meant the sort you would find in an elevator rather than the asteroid previously mentioned. Probably some sort of high efficiency electromagnetic system, like a hybrid's regenerative braking, instead of a big lump of lead and a 'wire'.

Does a Space Elevator not also have some cool power-generation properties due to the differing strengths of the Earth's magnetic field at either end?

That was one of the factors that I wasn't mentioning in my original post, because it didn't have to do with my very basic explaination. However, you are correct in that the counterweight should be slightly beyound GEO.

Which is why you either embed your power supply in the cable itself (like the subway's third rail) or power the thing internally.

I want to see where you got those numbers from. Blanket, unsubstantiated statements like that don't hold much water with me or many others on this board.

Obviously someone hasn't done an through study of the situation; catapaults work... after a fashion. but while they're an improvement over old fashioned rocketry, they still suffer from the need for massive amounts of acceleration to get the payload up to orbital speeds, which costs a massive amount of energy and requires similarly massive construction and maintenance. The advantage of an elevator is that the cargo is being lifted slowly, which is less strenuous on any human or other delicate cargo.

I skipped that chapter... I just wanted new stuff to buy and modifications to make...

More Ways To Die = More Ways to Confuse Yourself

counterweighting is structurally (and economically) a bad idea. Unlike in modern building elevators, the tether does not move, but instead, the lift vehicles climb it. Additionally, any extra weight reduces the mass of payloads.

The elevator structure can not usefully generate power. It's 40,000+km long (100,000km in the case of a pure tether, closer to 40,000km in the counterweighted model), the heating from transmission losses would be a threat to it's integrity. In fact, this means that the structure as a whole needs to be non conductive, hence why most proposed designs have the lift vehicle powered by ground generated lasers aimed at a photo voltaic panel opposite the payload module.

Geosynchronous orbit is any orbit that remains over the same point on the planet.

Lagrangian points are the stable points where gravity effects from two celestial bodies is countered by the centripedal forces involved in landing at that position. There are 5 lagrangian points around Earth.


As far as power goes, getting anything to the top of the gravity well requires a lot of energy. Mass x gravity x height = E. The question is efficiency. My aerodyamic-fu is weak but friction losses go up exponentially with velocity. Escape velocity is something like 11kps (24,600 mph). Reduce that to anything subsonic and your air resistance is 0.09% what it was.

SR does have orbital power satellites that can beam cheap energy down to the climber. Plus descenders should actually generate power once they get solidly into the gravity well. Mass x Gravity x height works both ways. Even after losses, a descender could provide 25% of the energy for a climber.

Exactly. The issue is simple: Efficiency.

To escape the gravity well, one needs to apply a certain amount of energy to the escaping object. This is the minimum energy required and, until we figure out how to produce antigravity, that amount is not going to change. However, current methods are very wasteful.

Rocketry has the primary problem of carrying its fuel on board; to accelerate that fuel, you need even more fuel, and to accelerate that fuel you need even more fuel, in a geometric increase.

A catapult, as kigmat pointed out, runs into the serious problem of air resistance; even if you start it above most of the atmosphere, you're still talking about accelerating something to orbital or near orbital velocities inside an atmosphere. We have a term for objects that do that: meteors. And if you add heat shielding to the launch vehicle, then your energy costs just went up, as you now have to accelerate the heat shield as well.

The nice thing about space elevators, however, is that all of the energy applied goes directly into increased height-above-ground; slow and steady wins the race in this case, and, additionally, the first elevator will be the hardest to build, as all of the materials will either have to be launched traditionally or made in space (both expensive options) but subsequent elevators can be built by using the first elevator to transport the materials up to GEO.

Can you even begin to imagine the wealth that the first space elevator will represent to the Mega that builds it?

It's Aztechnology that's closest in 2070, isn't it?

Cool....

Not!

There's some lovely stuff about a Space Elevator, with floorplans, diagrams and discussion in a Traveller:2300 module ["Beanstalk", by name].


Definitely worth reading, if you plan on using one in your sessions.

One of the best hard-science depictions of a space elevator in fiction would have to be Arthur C. Clarke's The Fountains of Paradise; it's actually what got me interested in space elevators to begin with.

Ah, that takes me back. I still love stutterwarp drives...

Good luck finding any of that material these days...

Wonder if you could use the Shiva concept of powering the Beanstalk, ie use the difference in electrical potential between the surface and the ionosphere.

There was a Sci Fi book written using such long ago,but they used lasers to bridge the gap, instead of a elevator.

WMS

That was more like the opposite of what you said but meh.


Unless you somehow come up with an idea how to superconduct along your 35000 km long self supporting cable or find a new way of storing energy that goes way beyond mere hydrogen fuel cells both proposed methods are impossible.


Then why do you post here? *points to edwards and runs*


Obviously someone should be less bigheaded considering the academic knowledge he presented so far; The massive amount of energy they require isn't that much higher then that of a climber considering that you can ignore atmospheric friction after the first 100km. Also you don't need any sort of motor or energy collector or whatever on board and thus will be somewhat lighter. Speaking of massive construction when comparing anything but the death star to a space elevator is a bit weird and maintenance would also be ok considering your maintenance crew can reach their workplace by car and failure of a tether in a tether catapult also is way less dramatic then loosing the whole elevator to a cascade.

Easy for me - it's on my shelf, with several other T:2300 products


I wonder why no-one is mentioning that power is simple - big solar sails tethered to the asteroid used to counterbalance the Elevator >shrug<

Considering there are manned Orbitals [such as the home of the Court] already in place, the know-how for manufacturing, maintenance and material sciences should not be too much of a stretch.

Simple... NO!

straight forward enough for you?

eh, SR4 introduced it as a level 10 mana-void or warp, so if you can get your magic up to 11 with 5 or 6 initiations and you know some level 11 spells, you're practically good to go and get power 1 spells out of your input neh? O.o
but yes, simple enough for me *g*
i just want a book titled:"SHADOWRUN: IIN SPAACEE!" with all that fluff and crunch to everything space-based in there ^^

In related news, Arthur C. Clarke has passed away.

Hey, look at that, people who know the math are already working on thsoe problems.
Or maybe this is more to your liking.

Apparently, the current idea is to use laser energy transmission in a wavelength that experiences minimal diffusion through the atmosphere and with a few dynamic tweaks to improve the rate beyond that.