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Future of Space Elevator Looks Shaky
Slashdot ^ | 12/9/8 | kdawson

Posted on 12/10/2008 7:41:35 AM PST by Clint Williams

lurking_giant writes

"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."


TOPICS: Technical
KEYWORDS: hinduropetrick; indianropetrick; magicropetrick; pipedream; spaceelevator; spaceexploration
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To: rjsimmon

In case of fire, please use stairs.


21 posted on 12/10/2008 8:08:05 AM PST by weegee (Sec. of State Clinton. What kind of change is it to keep the Bush-Clinton-Bush-Clinton Oligarchy?)
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To: Clint Williams
Slowing the climb would allow the space elevator to be drawn back to its stable point, perfectly vertical above the Earth's equator. But this could also make trips into orbit agonisingly slow, adding nine days or more to a climb that – at several hundred kilometres per hour – might already take about 15 days.

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.

22 posted on 12/10/2008 8:09:38 AM PST by kingu (Party for rent - conservative opinions not required.)
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To: kimmie7
Bellhop "You're going down"

Peyton Manning..."Yes I am. Fourth floor."

23 posted on 12/10/2008 8:10:33 AM PST by Deaf Smith
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To: weegee

along the lines of a dumbwaiter maybe...??...hmmmm (sorry to all waiters and waitresses)


24 posted on 12/10/2008 8:16:02 AM PST by tatsinfla
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To: Clint Williams; Titan Magroyne; KevinDavis

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.


25 posted on 12/10/2008 8:21:06 AM PST by Drumbo ("Democracy can withstand anything but democrats." - Jubal Harshaw (Robert A. Heinlein))
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To: Drumbo
was the undercard a Dune vs. Foundation battle?
26 posted on 12/10/2008 8:25:10 AM PST by Hegewisch Dupa
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To: Hegewisch Dupa

Asimov beats Herbert hands down. No contest really.


27 posted on 12/10/2008 8:26:46 AM PST by Drumbo ("Democracy can withstand anything but democrats." - Jubal Harshaw (Robert A. Heinlein))
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To: kingu
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.

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?

Regards,

28 posted on 12/10/2008 8:27:22 AM PST by alexander_busek
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To: rjsimmon

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.


29 posted on 12/10/2008 8:29:15 AM PST by Pistolshot ("Democrats don't show respect, they just demand respect " - ClearCase_guy)
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To: weegee

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?


30 posted on 12/10/2008 8:31:37 AM PST by Twinkie (TWO WRONGS DON'T MAKE A RIGHT!!!)
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To: Drumbo

agreed


31 posted on 12/10/2008 8:36:46 AM PST by Hegewisch Dupa
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To: Pistolshot
285,364,283rd floor please

With my luck, somebody'd fart at about the 10th floor.

Only 285,364,273 floors to go....

32 posted on 12/10/2008 8:41:17 AM PST by uglybiker (1f u c4n r34d th1s u r34lly n33d 2 g3t l41d)
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To: uglybiker
With my luck, somebody'd fart at about the 10th floor.

Ok, now I have TWO 27 inch monitors to clean off the sprayed coffee when I read this.

Thanks.

33 posted on 12/10/2008 8:47:34 AM PST by Pistolshot ("Democrats don't show respect, they just demand respect " - ClearCase_guy)
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To: Jonah Hex

Very punny.

lol


34 posted on 12/10/2008 9:01:27 AM PST by kimmie7 (***sigh***)
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To: r9etb

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.


35 posted on 12/10/2008 9:13:01 AM PST by HamiltonJay
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To: HamiltonJay

36 posted on 12/10/2008 9:15:45 AM PST by Scythian
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To: HamiltonJay
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?

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.

37 posted on 12/10/2008 9:24:12 AM PST by r9etb
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To: Clint Williams

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.


38 posted on 12/10/2008 11:08:04 AM PST by JohnBovenmyer
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To: r9etb
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.

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.

39 posted on 12/10/2008 11:09:14 AM PST by RansomOttawa (tm)
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To: alexander_busek

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.


40 posted on 12/10/2008 11:13:00 AM PST by RightWhale (We were so young two years ago and the DJIA was 12,000)
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