I think I understand the Andreas/windimut proposal, which may be workable, if the CNT is strong enough. Somewhat weaker CNT, is useable if the ribbon is thicker near geo altitude. If the loop is powered only at the bottom, it may be necessary to remove all vehicles from the system to permit accelerating the loop to higher kilometers per minute, as accelerating will stretch the pulling down portion of the loop. The pull down tension trancient will take days to reach the top pulley and more days to come back down the other half of the loop and take up the slack ribbon being produced by the bottom pulley.   Neil

My guess is a SE type elevator car can go non stop hundreds of stories, while traditional elevators typically only go 20 or 30 stories, max, before you have to change elevators. That would be a big plus for the elevator riders, and the SE type elevator might be safer than a traditional elevator, if the building is burning or an earthquake is in progress.  Neil

There seems to be strong agreement that significant energy can be obtained from conductive tehers in Earth's LEO, so my guess is most anywhere near Jupiter is a good source of tether enegy. The lower half of the SE is moving rather slow compared to Earth's magnetic field. Tether energy may however be helpful when and if we move vehicles toward Earth from the far end. Out going vehicles can get more energy than they can use from dynamic breaking, the last 50,000 kilometers of the SE.
Has anyone data on tether energy beyond LEO from ionized particles?   Neil

The elevator car will be cold, if it is a light color, which reflects sun light and laser energy. The infrared photovoltaic panels will be hot, as will the drive motors, so both are a possible source of cabin heat, when needed. It may be practical to electricly change the color of the cabin to keep optimum temperature. Some thermal and sound insulation is likely. Are the cenospheres presently available at a reasonable cost?
It may practical to adapt the space elevator cars for use in tall buildings, to replace traditional elevator cars.   Neil

Setting a goal of 2018 may be realistic, if cheap and abundent CNT = carbon nano tube ribbon is available soon. It needs to be abundent as the CNT will quickly be in demand for many projects, if it meets optimistic projections. I think Frank has confused km with miles. The altitude of the top end of the ribbon usually mentioned is 100,000 km = 60,000 miles. A few years ago there was mention of 91,000 km. The counterweight would need to increase mass by 2.7 times to use 60,000 km instead of 100,000 km, if another posters analysis is correct.
200 miles per hour may be correct for the rocket (perhaps something like an ion engine) unrolling the starter ribbon at and above geo altitude = 36,000 kilometers = 22,000 miles. Possibly correct for the thread laying climbers which will strengthen the starter thread and for the elevator car which will carry the payload on the finished SE. Somewhat faster is desirable for all three, but may not be safe. I suspect the speed will vary with conditions =  available power and how hot the drive motors and ribbon are. There will be a maximum safe speed, somewhat less than where the rollers start to tear up the ribbon even under ideal conditions. The ribbon will be cold when shaded by Earth, perhaps as cold as minus 150 degrees c. The rollers will heat the ribbon, sunlight will heat the ribbon, the lasers will heat the ribbon, tension transcients will heat the ribbon. It may occasionally be necessary to reduce the laser power, to avoid possible heat damage to the ribbon, especially in Earth's upper atmosphere where atomic oxygen is present.   Neil

Hi Frank: 60,000 kilometers = 37,000 miles may be too short as it leaves only 15,000 miles = 24,000 kilometers beyond GEO altitude requiring a very heavy counter weight which would put a lot of strain on the outer 15,000 miles of ribbon. There was however early talk of a 91,000 kilometer ribbon.
Yes, the 91,000 kilometer, or longer ribbon can throw the retired climbers at the moon where they will make small craters. A soft landing or stable moon orbit would require a small rocket and a guidance system. Either way, an error could result in the climber burning up in Earth's atmosphere much later.
I agree, someone may want the retired climbers eventually, but soon is unlikely. It would be sort of like storing a bunch of 1999 computers in hopes that you can find someone who will want them later.   Neil

Ideally a vehicle that can deliver 100 tons to GEO orbit will start unrolling starter ribbon just before it reaches GEO altitude, but will keep moving out ward to about 100,000 kilometers when the last of the ribbon is unwound.
Several alternatives are practical if the ribbon fails to unroll completely or the vehicle can't make it quite to 100,000 kilometers. In any case several thread laying climbers can begin inspecting and repairing weak spots in the ribbon, if the heavy lift vehicle can carry the extra load. If the heavy lift vehicle is only 30 tons, the ribbon safety factor will be tiny, and failure before attachment at the anchor at sea is high risk. If the CNT = carbon nano tubes meet optimistic projections, less than 30 tons starter ribbon may be practical, but more than 200 thread laying climbers will be needed to bring the ribbon strength to daily 10 tons payload or bimonthly 20 ton payload to the far end. At an average speed of 200 kilometers per hour, it will take 500 hours = 21 days to reach the far end. Hopefully 500 kilometers per hour will prove practical. I suspect the various tension transcients and other transcients on the ribbon will determine when the next thread laying climber or pay load can be launched. Climbers will need to inspect the ribbon and make repairs through out the useful life of the ribbon in my opinion.   Neil

If a laser is 20 kilometers from the base and the the lifter is at 20,000 kilometers, the beam width (200 meters?) of the laser may be sufficient to hit the ribbon at 36,000 kilometers, especially if the ribbon is curved slightly. You are correct the laser beam would be weak and intermitant, so most of the geo station energy should be from sun tracking solar cells.   Neil

I don't think 200 retired lifters at 100,000 kilometers is a major problem, but planning to dump them into solar orbits will really upset some people. If CNT (and heavy lift rockets) exceeds optimistic projections, 100 lifters may be enough. With bad luck, we could use 999 lifters, whose mass would require us to shorten the ribbon. Most of the lifters will need repairs after traveling 100,000 (or a bit more) kilometers. Some however could move slowly back toward GEO altitude, if the surface lasers can deliver enough power to them at about 100,000 kilometers.  There will be additional options for building the subseqent space elevators, making 150,000 kilometer ribbons practical.
If the far end of the ribbon is optimised for low electrical resistance, the dynamic braking of out going lifters could power a few lifters moving back toward GEO altitude.
I'm still waiting for a discussion of passing on the ribbon and details of attaching fixed items to the ribbon, so that they won't interfer with high speed lifters and elevator cars. If the rollers pinch only 45% of the ribbon width during passing, modest rocket motors would reduce the stress placed on the ribbon.   Neil

It's true that the space elevator provides little horizontal speed  the first few thousand kilometers. Even then considerable delta V is needed to get into LEO = low Earth orbit. Except for single stage to orbit and possibly Launch Loop, this is true also of competing systems.
Very low cost CNT = carbon nano tubes may make Launch Loop practical, but there are several other possible show stoppers for Launch Loop.   Neil

ET that are even slightly more advanced than Human best are likely monitoring Earth covertly, and cautiously to avoid transfering technology and ideas that might make humans even more dangerous.
While ET may have found something better than electromagnetic photons = radio for communications, radio is easy, so radio likely has some applications even in a class 2 civilization if there are any.
A technology which allows instant communications to everywhere is likely to have high noise level if there are a trillion simultanious users. Please embellish, refute and/or comment.  Neil

The ring station can receive laser energy that misses the lifters/climbers/elevator cars. With some modifcations, the ring station may be quite helpful. The diameter needs to be large as the ribbon moves to avoid space junk and the climbers/ lifters/ elevator car also causes some horizontal movement of the ribbon. My guess is movement is least at GEO altitude due to the larger local mass. The ribbon is tapered.
For a break above GEO altitude the best strategy may be to dump all or part of the counter weight, to slow the escape of the outer portion. Splicing in a replacement section may be possible increasing the total length to perhaps 150,000 kilometers. Elevators and repair climbers near both ends can fine tune the the ribbon speed by reversing direction and/or firing  modest rocket engines.
A longer ribbon provides faster release at the far end, so the repaired space elevator may be more valuable.   Neil

Another post in another thread, suggested drop from 18,000 miles as a low energy way from space elevator to LEO. 4000 kilometers or less will work, but requires more energy to get into LEO. If the rocket fails to ignite, you burn up in Earth's atmosphere.  Neil

By any method, it will take all day, if not longer to get to LEO = low Earth orbit, for typical travelers, just as it does take almost that long to fly to another city by airline. If the space elevator takes 8 hours to climb to an altitude of 4000 kilometers where it is dropped off the ribbon to get enough speed for LEO, you will be in the desired orbit about 9 hours after the elevator starts up the ribbon. Considering the space elevator is much less costly, I think it will be very competitive for both passengers and cargo to LEO and GEO orbit. Admittedly 200 hours to the far end of the ribbon is an ordeal, which may attract few human travelers. Does anyone think the elevator can average more than 500 kilometers per hour safely?   Neil

These platforms would be mobile, which would allow the elevator, with sufficient warning, to avoid orbiting satellites and debris by moving the anchor end of the cable back and forth about 1 km, pulling the ribbon out of the path of an oncoming object. While debris and other objects down to 10 cm in diameter are currently tracked, objects with diameters as small as 1 cm are a potential threat to the elevator. As a consequence, the current elevator system design includes a high-sensitivity ground-based radar facility to track all objects in low-Earth orbit that are at least 1 cm wide [see illustration, "Watching the Skies"]. A system like this was designed for the International Space Station but never implemented.

Eliminating erosion from atomic oxygen at altitudes of 100 to 800 km would be the job of thin metal coatings ~Each of the two starter ribbons has surface area of 200 billion square centimeters = 20 million square meters. If the metal coating averages one nano meter thick, the total metal coating is  equivent to two centimeters by one meter by one meter = about 50 kilograms. Will each micro ribbon (layed by a climber) require a metal coating? We can omit the metal coating for 99% of the 100,000 kilometers, but that may mean trouble if the ribbon brakes a few hundred kilometers above the anchor and the bottom portion is lost twice. Is even a 1000 nano meter metal coating realistic? Will the metal coating adhre to the CNT reliably over a 500 degree c temperature changes and being squeezed daily by climber rollers?~ applied to the cable. Radiation damage would be mitigated by using carbon nanotubes and plastic polymer materials that are inherently radiation resistant ~it seems to me that each change of a carbon nucleus weakens the nano tube significantly as it will be a flaw in the almost perfect molecule/crystal~.

To avoid problems with cable oscillations induced by tidal forces, my ribbon design calls for a natural resonant period—7.2 hours ~the transient needs to propagate 5000 kilometers (average)per hour if the effectve length is 36,000 kilometers/ that seems much too fast for a very thin ribbon, mostly under light tension/The outer portion is about 64,000 kilometers long and will have oscillations during micro ribbon laying. My guess is the oscillations can be useful~   that does not resonate with the 24-hour periods of the moon and sun. Any oscillations that do occur would be damped by the mobile anchor station ~likely effective the bottom thousand kilometers, but my guess is other measures are needed for 99% of the ribbon. Please correct any errors I have made.   Neil~.