Space elevators

Taking the basic idea from Hindu epic called RAMAYANA
Arthur.C.Clarke once gave an interesting idea at a convention.
SPACE ELEVATORS
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the whole idea goes like a big Jack of the car used when tyres get punctured. the space elevator will be a big jack like thing with a big base.now,whatever has to be sent to space will be just attatched to it and with a rotating crank shaft system it"ll be taken upwards,pushed with a great force.Arthur has actually conducted a research on this and says that the cost of todays launches is pretty high,with this it"ll reduce considerably.the material will be friction,heat resistant.the depth at which it "ll it will be kept (inside the earth)will be equal to exosphere's begining.
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any comments?
bye!.

 

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ehhhh....
It just wouldn't work. To reach the escape velocity of earth vertically, the acceleration will be so great that the g-forces created will just crush everything-not to mension human. Even it is achievable, the energy required to give such a force will also be great, just like lauching a rocket.

 

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about

the possible answer to this problem is antigravity, just needs to be discovered though. I duno, maybe militarists have it already.

 

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read more...

in arthur c. clarkes book 3001: The final oddysey their is a ring around the earth, space city. their are four "towers" going up to it these are in affect space elevators they are made of diamond some how and the "elevators" in them use damnit cant remember...anyways when the " bubbles surrounding the elevator their is NO acceleration and by that time they have discoverd 0-energy. i think it is possible to build a space elevator.
it would probably use a type of magnetics system to propel it upwards at the required velocity.

 

Re: read more...

Thats exactly what he told and thats how he started his speech,as my father explained to me.

 

Space elevators first came to prominence in two novels written almost simultaneously; Arthur C. Clarke's The Fountains of Paradise and Charles Sheffield's The Web Between the Worlds. So close were they, in fact, that my edition of Web has an afterword by Clarke commiserating with Sheffield for the unfortunate timing, and assuring the readers that the parallels are coincidental. I actually prefer Sheffield's book, but then I'm a big fan of his stuff.

Anyway, these are gradually coming closer to possible. Until recently, the idea of a rope strong enough was almost inconceivble. Now, however, our good friend the nanotube may be coming to the rescue. Really, is there anything buckyballs can't do?

The idea is an asteroid in geocentric orbit would have two tethers; one anchored to the Earth and the other going out in the opposite direction. For more information check out a few pages such as Tethers Unlimited (http://www.tethers.com) or http://www.spacescience.com/headlines/y2000/ast07sep_1.htm?list , a story from NASA's excellent science site.

 

Engineering

The most logical way to acheive this Space Elevator would be to use a worm gear assembly, similar to the mechanism used to advance the laser head of a CD player.
The worm gear turns and so the 'shuttle' rises or lowers.
Easy.

 

Well I don't think the lift would have to reach escape velocity. You would just need enough force to lift the thing up the elevator.

I will scan thru my copy of 3001 and see how he explains it.

 

Idea of space elevators should take inspiration from CONTACT.it gave me an interesting thought.the idea is that the elevator falls on a magnetic field strong enough to push it upwards.or one can first rotate the elevator in the field at high speeds and then just like a sling it throws the craft(or elevator)upwards.the accelaration will be very high of such a craft.any inputs or corrections to the thought will be welcome.

bye!

 

I just read 3001

The space elevator was made out of diamond (mined from the aftermath of Jupiter's ignition)

The kind of drive that was used was an "Inertial Drive" that needed no fuel whatsoever. Any Craft of any size could go on forever witohut refueling.

 

Space Elevator - Revisited

According to this article the only real technical issue standing in the way of a Space Elevator is the quantity of carbon nanotubes that are being produced. This number is moving into the tons/year and only getting greater, so this guy says we can make a Space elevator for about 6 billion dollars in the next 15 years.

Are the time frame and financial predictions are accurate? What about safety of an earth-based space elevator? Is its worth it right now?

I would guess that any estimates from people involved in the Space program require tweaking. Look at the Space Station, for wxample. This would cost a ton I am guessing, however, the return could potentially be tremendous. The article suggests within 6 years of operation you could have double your money back.

Financial returns aside, I would have to say that this would be one of the greatest things humans have ever created. It would change the world. Humanity would finally be able to start communities on the Moon (I can't wait to go visit "Moonhattan"), Mars, and the asteroids. Science (certain branches anyhow: cosmology, astronomy, etc.) could jump by leaps and bounds with cheap access to space.

Peace.

--- Edit: fix html link ---

 

I think you could also say the mankind would go by leaps and bounds. Not to mention the benefits we would reap in the process of all the new tech required.

 

Embedded into a composite, nanotubes have enormous resilience and tensile strength and could be used to make cars that bounce in a wreck or buildings that sway rather than crack in an earthquake.

Nanotubes still cost 10 to 1,000 times more than the carbon fibers currently used in composites. And nanotubes are so smooth that they slip out of the matrix, allowing it to fracture easily.

Strength: 45 billion Pascals - High-strength steel alloys break at about 2 billion Pascals

Resilience: Can be bent at large angles and restraightened without damage - Metals and carbon fibers fracture at grain boundaries

Current Carrying Capacity: Estimated at 1 billion amps per square centimeter - Copper wires burn out at about 1 million A/cm 2

Heat Transmission: Predicted to be as high as 6,000 watts per meter per Kelvin at room temperature - Nearly pure diamond transmits 3,320 W/m·K

Temperature Stability: Stable up to 2,800 degrees Celsius in vacuum, 750 degrees C in air - Metal wires in microchips melt at 600 to 1,000 degrees C

Cost: $1,500 per gram from Bucky USA in Houston - Gold was selling for about $10/g

 

I though about this a bit more about this overnight.

In light of recent events, I wonder if a real concern here is safety. A big, stationary tower 40,000 km high is a sitting duck. A plane or three ramming it would do vast damage, especially if it's half completed. How would you protect it? And then there are natural problems, like meteors and lower orbit space debris. You'd have to proof it against something moving 7 or more km/sec, which may prove difficult.

In large-scale engineering projects, the devil is always in the details. In theory, you can build a 5,000 ft building, or a 15 mile wide bridge. We even have the materials today to do it, and proven engineering methods to rely on. Even so, the Gibralter bridge is projected to cost $20 billion.

Something like a space tether requires a tremendous amount of basic research, plus a lot of engineering and fabrication research, before you can even start. For example, the tether is going to build up one hell of an electric charge cutting through the Earth's magnetic field. Didn’t a shuttle mission conduct a tether experiment a couple of years ago where air trapped in the tether material bubbled out and caused a plasma burst that burned up the tether? What happens to the nanotubes over time? Does the high electric charge coupled with extreme temperature changes do anything to them?

Wouldn’t this be the world’s biggest lightning rod? How would decades of constant lightning strikes affect it? How does ONE lightning strike affect it? How does this thing interact with the upper atmosphere? What about the effect of storms or extremely high winds on the cars going up and down? What happens if a car malfunctions on its way up? If it jams on the cable, how do you get it down? What if the electrical system fails? How do you test these vehicles when you don't have a prototype tether to test them on?

I think 15 years is very optimistic. I'd like to see a long-term study.

Peace.

 

I have here a 4.8 megabyte PDF file from NASA about space elevators, construction and all. I am not sure if I can post such a large file as an attachment to sciforums, but I want to make this available to everyone. Any ideas? No, I can't stick it on my own website.

 

Well, none of my email options will accept such a large file, so I can't send it to anyone that way. I'll try to attach it here, see what happens...

Nope. Oh well. I'm taking my computer home this week from uni, and I should be able to FTP it onto a site from there. So, you'll all just have to wait a couple of days.

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Looking forward to it. Do you remember the download site?

Peace.

 

Can't find the file again at NASA. I'll just stick it on my own site this week. Until then, you might enjoy this: http://science.nasa.gov/headlines/y2002/27mar_stoplight.htm

 

From NASA Flight Projects Directorate

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perhaps this is the link:

here

 

Cool pic. But does the perspective look right to you guys?

Peace.