Author Topic: Japan hopes to turn sci-fi into reality with elevator to the stars  (Read 9440 times)

Offline William Barton

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Japan would have to gain approval from some country on the equator to build the elevator. The equator  passes across the land of 11 countries: Ecuador (including Galapagos Islands), Colombia, Brazil, Sao Tome &  Principe, Gabon, Republic of the Congo, Democratic Republic of the Congo, Uganda, Kenya, Somalia, Maldives, Indonesia. Which one is politically stable enough to trust with a $ 9-billion dollar space elevator?

Most of those countries are stable enough when you have several cables. Besides a good portion of the equator runs through open water with no territorial claim.

Without reflecting on cost and technical feasibility, I found myself wondering which equatorial seamount in international waters would be best, and whether or not a corporate entity could lay claim to it. Secondarily, does the seaside end of the cable need to be anchored to seabed, or would a big floating platform a la Sea Launch (but bigger, since I assume you'd probably want a nuclear reactor aboard for the powerplant) do the job?

Offline Patchouli

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Japan would have to gain approval from some country on the equator to build the elevator. The equator  passes across the land of 11 countries: Ecuador (including Galapagos Islands), Colombia, Brazil, Sao Tome &  Principe, Gabon, Republic of the Congo, Democratic Republic of the Congo, Uganda, Kenya, Somalia, Maldives, Indonesia. Which one is politically stable enough to trust with a $ 9-billion dollar space elevator?

What is the worst case scenario for 36,000km (or more) of "super light" lift cable falling back to earth due to some malfunction or miscalculation? Would if fall in one place or wrap around the earth? What type of damage would it do?

I'd have it located in Brazil because it's politically relatively stable and has a large industrial base.
Locating it inland safe from typhoons and tropical storms would be a smart move.

BTW a falling space elevator wouldn't do as much damage as one would think.
Much of it would move into a higher orbit while what does comes down would mostly burn up since it is just carbon nano tubes.

It might even be possible to repair the elevator after the incident.

The biggest danger to such an elevator would be MMOD damage from stuff in LEO.

One chicken and egg issue with building it is large quantities of long carbon nano tubes must be manufactured on a large scale first.

Also an RLV and some sort of cheap transport from LEO to GTO is needed until the first elevator is finished after that it can become self sustaining and lift materials to finish it's construction and then help construct other space elevators.

Dead sats could be used for the counter weight for the first space elevator you do need a counter weight mass much more massive then anything you are trying to lift since the tension in the cable must be greater then the mass of the object climbing it or you'll literally end up pulling it down.

If a climber can be made fast enough all one would need to reach the moon would be a craft with only 2x the delta V of an Xprize vehicle.

Though I heard it could take a month to reach geostationary orbit on an early space elevator which means any human cargo is still stuck riding costly rockets.
« Last Edit: 09/25/2008 08:21 pm by Patchouli »

Offline iamlucky13

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I'd have it located in Brazil because it's politically relatively stable and has a large industrial base.
Locating it inland safe from typhoons and tropical storms would be a smart move.

BTW a falling space elevator wouldn't do as much damage as one would think.
Much of it would move into a higher orbit while what does comes down would mostly burn up since it is just carbon nano tubes.

It might even be possible to repair the elevator after the incident.

The biggest danger to such an elevator would be MMOD damage from stuff in LEO.

It doesn't need to avoid tropical storms. See the map below of all tropical storm tracks from the last 20 years. Can you guess the latitude of the empty stripe?

Also, depending on the altitude and mass of the counterweight and the elevation a sever occurs at, it may not simply move to a higher orbit. It may have escape velocity.

I believe there's been some papers written on MMOD to a space elevator ribbon. It comes down to oversizing it so that accumulated damage over a given time period does not overly weaken it.


Offline alexterrell

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Japan would have to gain approval from some country on the equator to build the elevator. The equator  passes across the land of 11 countries: Ecuador (including Galapagos Islands), Colombia, Brazil, Sao Tome &  Principe, Gabon, Republic of the Congo, Democratic Republic of the Congo, Uganda, Kenya, Somalia, Maldives, Indonesia. Which one is politically stable enough to trust with a $ 9-billion dollar space elevator?

Most of those countries are stable enough when you have several cables. Besides a good portion of the equator runs through open water with no territorial claim.

Without reflecting on cost and technical feasibility, I found myself wondering which equatorial seamount in international waters would be best, and whether or not a corporate entity could lay claim to it. Secondarily, does the seaside end of the cable need to be anchored to seabed, or would a big floating platform a la Sea Launch (but bigger, since I assume you'd probably want a nuclear reactor aboard for the powerplant) do the job?
I can't find the reference but the most detailed study I've seen envisioned a platform floating in the Pacific off Ecuador, in a region with few storms.

The platform would move to avoid any tracked space debris.

The elevator itself is a ribbon, wider at the top and narrower near Earth. Smaller debris would pass through the ribbon, making a small hole but not breaking the ribbon.

The first piece of ribbon would be launched with about 20 tons in GEO. Then climbers would stitch on additional ribbon to make the structure stronger and stronger. The ribbon would be less than a mm thick, but up to a few metres wide at the top.

Elevator cars would climb the ribbon using wheels, powered by laser (laser solar cells can achieve 50% efficiency). Only about the first 1,000km of climb would be powered from the launch ship, after which a mountain top laser in Ecuador would take over (I'd suggest rapidly adding a space based, solar power laser beaming downwards).

IIRC transit time was on the order of a few days.

All space elevator design suffer from a long transit time which makes radiation a real concern.

On the other hand, a hypersonic rotovator could be built using today's materials (Spectra 2000?). This could orbit at 7km/s, pick up at 4km/s, and release at 10km/s, which is about right for GTO and LTO.

« Last Edit: 09/26/2008 09:39 am by alexterrell »

Offline iamlucky13

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On the other hand, a hypersonic rotovator could be built using today's materials (Spectra 2000?). This could orbit at 7km/s, pick up at 4km/s, and release at 10km/s, which is about right for GTO and LTO.


9000 mph rendezvous's are a rather ambitious goal, and unless I completely misunderstand the rotovator concept, it would need a reboost after every launch.

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