Skip to comments.Future of Space Elevator Looks Shaky
Posted on 12/10/2008 7:41:35 AM PST by Clint Williams
"In a report on NewScientist.com, researchers working on development of a space elevator (an idea we have discussed numerous times) have determined that the concept is not stable. Coriolis force on the moving climbers would cause side loading that would make stability extremely difficult, while solar wind would cause shifting loads on the geostationary midpoint. All of this would likely make it necessary to add thrusters, which would consume fuel and negate the benefits of the concept. Alternatively, careful choreography of multiple loads might ease the instability, again with unknown but negative economic impacts."
So the space elevator is going down?
< ducking >
(Hey, one bad pun deserves another!)
How about a space Escalator? ;)
One such detail, btw, would have been actually deploying the thing in the first place. Turns out that just dropping the cable would require an immense launch campaign.
285,364,283rd floor please
Well there's a twist.
Seriesly, though, from the time I first heard about this I thought the coriolis forces would be a deal-killer for it. Anything that can create a hurricane in the lower levels of the atmosphere is going to be absolutely devastating on a structure that tall.
maybe stairs or a ladder....??
Simple rockets can probably beat the space elevator in terms of cost. I’m talking about private industry, not government-funded space shuttles.
Though space elevators and other concepts can still be viable on the moon and Mars.
This is the equivalent of the “studies” 25 years ago that said Missile Defense would never be possible because “you can’t hit a bullet with a bullet”. It is simply too early in the research cycle to say what is and is not possible when we haven’t even developed the nonofibers that would be the building blocks of the cable.
To point out obstacles that ultimately would have to be overcome is fair. However to issue judgments on project viability before these and other obstacles can be addressed is not science, nor is it engineering.
The Americans with Disabilities Act requires a space ramp with a slope no greater than 1 inch per foot horizontal distance instead of stairs.
“determined that the concept is not stable.”
Something I noted when it was first discussed.
well then those ideas are out or the aclu will be on my a**
I was wondering how long it would take for reality to set in. And, if the thing ever broke... What a ride THAT would be! Insurance policy would cost a few bucks.
They should start with a stairway to heaven.
A really long rope? Maybe?
No matter how high, there will always be somebody that wants to get off on the second floor...
Mmmm. Could BE!
In case of fire, please use stairs.
Well, 100 km/hr is a 15 day journey, if you're talking several hundred km/hr, then you're cutting that down to five days.
Which is, admittedly, a heck of a lot slower than I imagined it would be, but the supposition is that for stability sake, they're starting to think maximum speed would be about 60 km/hr, which would mean the 36,000km journey would take 25 days.
However, humans tend to go to low earth orbit - the space station's at 350km from the earth - 60km/hr to there would only take about six hours, a far more practical situation, though still one heck of an interesting onramp since all the rest of the traffic is going 27000km/hr faster than you are.
Peyton Manning..."Yes I am. Fourth floor."
along the lines of a dumbwaiter maybe...??...hmmmm (sorry to all waiters and waitresses)
Told ya so / Wayback machine ping.
I was involved in a huge troll war on another forum years ago arguing just these concepts. I advocate a space catapult constructed in high mountains instead, which would be much more effective, easier and cost friendly for moving large cargo.
It was basically an Arthur C. Clarke (space elevator) VS. Robert A. Heinlein (space catapults) Science Fiction debate that turned nasty.
Asimov beats Herbert hands down. No contest really.
Yes, admittedly, you'd still have to transfer from the Beanstalk (which, like a very tall tower, is effectively motionless relative to the Earth's surface) to the untethered space station whizzing by (at about 8 km per sec) in low Earth orbit.
People currently "tend" (a curious choice of words on your part) to go to LEO not because there's anything intrinsically interesting there, but rather only because it's the nearest/lowest/cheapest "spot" which is nonetheless already in "true" space.
I, personally, have no problem with a long, stately "drive" into geostationary orbit. Who's in a hurry?
Can you imagine hitting all the buttons for the rest of the floors above you before you get off on yours? That sucker would never come down.
The Babelians tried that once, and now they’re set to try it again. The thing sounds goofy on the face of it, but if God allows it - who am I to say?
With my luck, somebody'd fart at about the 10th floor.
Only 285,364,273 floors to go....
Ok, now I have TWO 27 inch monitors to clean off the sprayed coffee when I read this.
I’m no physicist, but isn’t the Coriolis force a fictitious force? Its only an observation of behavior by the reference of being in a rotating environment?
I understand that as the elevator climbs the ribon, it will continue to need to move at an ever faster rate of speed (keeping up with the rotation of the ribbon) in the direction of the earths rotation, but the drag of its movement I would think be minimal relative to the overall system.
I assume I am just missing something.
The coriolis effect is real. Look at the rotation direction of a hurricane in the northern and southern hemispheres, for example, or the direction of "swirl" as water flows down the drain.
The reason why is, the Earth really is a rotating environment; and the acceleration is "fictitious" only from the perspective of an inertial reference frame.
As for "small forces" -- in space, small forces have significant effects because there's no friction to moderate those effects. Thus, solar radiation pressure will be a big deal.
Also, you need to realize that the reason a space elevator would work at all, is because the center of mass of the system is in a geostationary orbit. If you attach something massive to the tether and start cranking it up, the center of mass will be displaced downward, and thus the tether would want to move forward. The response is to crank something upward to keep the center of mass approximately the same; or to fire thrusters to adjust.
Solution might be to build a smaller scale elevator first on the Moon if you don’t trust your computer modeling on the Earth one.. Current materials should be strong enough for that and the risks of failure are far less. Work out the theoretical bugs there and then put the carbon nanotubes to work for the earth one. Of course such would be the most expensive engineering model in history, but conceptually it could help and would eventually make it much cheaper to get lunar raw materials into space for future construction products on SF time lines.
Actually, the Coriolis effect doesn't affect anything as small as a drain - it only noticeably affects large-scale phenomena such as hurricanes (as you also point out). In your sink, the direction of swirl is determined by the design of the fixture, and it's entirely possible to have drains in your house that swirl in both directions.
The point of the space elevator is to launch payloads to interplanetary space rather than to earth orbit, although it would suffice for geostationary orbits.
Sure, but it is the sideways force upon you when you move from the equator to the pole and is a major force in atmospheric modeling.
Somehow this failure must be connected with global warming in the future.
Two words: Ballast Weight.
Increase it slightly so the centre of mass is always above geostationary orbit position. Tension on the cable is slightly greater, but it's always stable.
A Moonstalk would have lower stress on the cable, but because of the moon's lower rotation, it would have to be on much larger scale (maybe 4 times as long as an Earthstalk) - and the lower cost of lifting mass of the surface by reaction drives or surface catapult means it's not the economic way.
Now a MarsStalk is another matter: both shorter and lower stressed than an Earthstalk.
Let's look at that. As the CM is above GEO, it will want to fall back. The tether has fixed length, so it will pull the CM downward. The net effect would most likely be that there's a slight catenary curve to the tether, with the CM at GEO, and you're back to the same situation. And that's just with the system itself -- once you add moving masses along the tether, the whole thing gets more dynamic.
Not if it's moving faster the orbital velocity for the altitude (as it would be)
Im no physicist either but there conservation of angular momentum. This means that as the elevator moves up, its angular momentum will make it slow down relative to the rotation of the earth. Its what drives the Coriolis effect and what makes an ice skater spin faster when they pull in their arms and legs.
I don't think so. The CM is still in orbit. FOr orbits, faster=higher=backward. I don't think a tether will change that.