Hi Andreas: Does that mean you are doubtful that the oscillating ribbon can get the climber to 91,000 kilometers in one day? From 91,000 kilometers we can crash into any object in the inner solar system without any fuel or propulsion in the payload. We will need some payload delta v to make an orbit insertion or a soft landing at the destination. The space elevator may still be a good idea, even if we have cheap access to LEO and GEO. If we build a 200,000 kilometer space elevator I think we can pass Saturn's orbit in about one year/ 52,000 miles per hour with respect to Earth's surface when the payload leaves the ribbon?   Neil

Perhaps you can give us more details on your first paragraph. About 24,000 miles is the minimum length for the Brad Edwards' space elevator. We can do a bolo (soon) which is much shorter, but also much different. A bolo is a thousand miles or so of ribbon flipping end over end in low earth orbit. It is oriented so the low end travels about 16,000 miles per hour with respect to Earth's surface, so a hypersonic rocket is needed to attach the payload to the low end. Timing is very critical as the low end and high end switch places several times per hour. The payload is released near the high end about 1000 miles higher and about 3000 miles per hour faster. With stronger ribbon, which may be available soon, the bolo can flip more times per hour. Faster means the release speed is faster, perhaps fast enough to hit the Moon or Mars without any fuel or propulsion. Some payload propulsion is needed to make a soft landing at the Moon or Mars. Making the bolo longer has some advantages, but not much.
If the tips of the bolo dip as low as 65 miles altitude, air friction losses slow the bolo more than can be recovered with some solar panels near each end.   Neil

Apparently Virgin plans to fly Space ship two in 2010 to 110 kilometers altitude, sub orbital, with a payload of about 1.3 tons. The 20 ton starter ribbon needs to be lofted to about 36,000 kilometers, which may be possible with space ship 3 or some other private corporation. With bad luck on ribbon strength, the starter ribbon may weigh as much as 100 tons.  Neil

The climber on an Edwards type ribbon is travening much less than orbital speed, so graviy at 300 kilometers altitude is still about 0.99g The climber must overcome significant gravity until it reaches an altitude of about 35,000 kilometers.
Some beam spreading occurs, so a beam which has traveled a million kilometers total over many reflections requires a prohibitably large mirror at both ends, especially if the mirror aiming is typically in error by one second of arc. At visable light wavelengths, the mirors also require extreem surface precision to avoid scattering most of the light out of the beam. That is not to say the concept is entirely worthless, but we will be disappointed if we expect a big improvemement.  Neil

Banning vehicles is going too far, but we can get more use from the railroad tracks that are in place and do pilot programs with a few more no vehicle communities. Zoning our cities so most everything is available in each square kilometer (or an adjacent square kilometer) would reduce driving across town for many of us.   Neil

If your aircraft cariers ect have an average density of more than one kilogram per cubic meter = 1/1000 th the density of water, they will float below the cloud tops of Venus where the sulpheric acid clouds are found, and little solar energy is available. CNT = carbon nano tubes may permit a low enough average density to stay just above the cloud tops which I agree is ideal, except the habitats will fall if large quantities of carbon dioxide leak in. I agree linking them (with air locks) makes falling very improbable as it is very unlikely more than one would have a bad leak. Floating cities high in Earth's atmosphere have much the same problem, except the inhabitants might survive the fall of their habitat to Earth's surface.   Neil

Unless the new iceage is worse than the previous iceages, I'm possibly safe in Florida: But survivil will be difficult 1000 kilometers farther from the equator and perhaps no survivers more than 2000 kilometers farther from the Equator. Solar mirrors, in solar synchonous semi polar low Earth orbit, could ease the suffering of people who live more than 30 degrees from the Equator.   Neil

Some experts think the Sun's Energy output will increase about 1% per 100 million years, so Earth and Venus will be in trouble in about 3 billion years when the Sun produces 30% more energy. Mars will then have comfortable temperatures, but in a few billion more years (perhaps sooner) Mars will also be too hot. No need to worry, 3 billion is 3000 times 1000 times 1000 which is extreemly far in the future. The sun is not expected to change detectably in the million years, it may take to terraform Mars and part of Venus.   Neil

I'm old and poor, so I can't travel or help with the cost, but I am a generalist, so I occasionally have a useful slant that the specialists miss. Will you use pinch rollars as needed for CNT = carbon nano tubes? They are only about 30% efficient. Perhaps you could interest Tesla Motors in loaning you a 56 kilowatt-hour battery pack. I think it can supply a megawatt briefly, and get your climber to the top in seconds instead of minutes. Tesla would get great publicity, if the pack was still 90% charged after taking your climber to the top in seconds.   Neil

Hi Andreas: Let's not make it harder than reality. Earth's gravity is down to 1/4 g at about 6000 kilometers altitude and 1% of g at about 60,000 kilometers, so the lunar elevator ribbon has rather modest stress, unless the tip comes within 60,000 kilometers of Earth. I agree 4 or 5 times longer increases the stress a lot, but the prototype lunar elevator can likely be as short as 70,000 kilometers.
The lunar elevator will be attached near the center of the visable (from Earth) surface of the Moon.  Neil

I'm not sure how I missed this thread before. A possible problem is the tension transient takes something like 7 hours to propagate the 91,000 kilometer length of the ribbon, so we would have to plan ahead carefully for the tension transients to reach the climber simultainiously.   Neil

I agree: One of the tie down ribbons should at least be shiethed in CNT, so climber traction can be analyzed. CNT is very slipery, like teflon, so traction may be a problem even with pinch rollers.   Neil

Unlike an Earth elevator the terminas is moving slower than Venus, but occasionally in the correct direction for a trip to Mars, but the orbit needs to modified with considerable delta V so the elipse reaches Mars. The payload of dry ice would hit Mars at very high speed, unless considerable more delta v slowed the payload. Perhaps it does not matter. Would most of the carbon dioxide remain in Mars' atmosphere if the dry ice evaporates at 60,000 kilometers altitude instead of at the surface of Mars?
The shading disk would effectively shade only the last few kilometers of the ribbon, unless it is planet diameter.   Neil

As I understand the Andreas oscillating ribbon, the starter ribbon is similar to the Edwards starting ribbon except it has two down segments about 38,000 kilometers long, and is thus shaped like an upside down Y. The launch rocket can lift it to 35,000 kilometers or somewhat less at a bit more than GEO altitude orbital speed. The third stage can then continue to lift the reel of ribbon and unwind the two legs of the Y toward Earth. The decending Y legs may need some minor propulsion to avoid tangling since they are both moving in the same direction toward Earth. The single ribbon part is unwound from the reel until it reaches an altitude of 90,000 kilometers or a bit more. The unwind speed likely cannot exceed 3600 RPM, so the third stage may need to slow the falling away from Earth for as long as 24 hours. This is a bit of a balacing act as the starter ribbon is fragile, but needs to maintan enough tension to counter the weight of the double ribbon below GEO altitude. The GEO altitude portion needs to stay close to GEO altitude orbital speed or the ribbon will possiblly collide with GEO satellites. Initially 2 anchor ships are needed, one for each down leg of the upside down Y. The oscillations can now be started one up and one down 180 degrees out of phase. The anchor ships can now be merged as correllis will keep the ribbons apart as long as they are one up and one down. We can now launch a climber which lays a strengthening thread, on the ribbon which is slipping though the slot. This may not be possible if the speed difference is 100 meters per second or more. It may be practical to allow the gripping leg to slip some to reduce the speed to the maximum thread laying speed. Alternatelly we can just stop laying thread, until the speed difference is low enough. The climber likely needs some additional power for fine tuning the speed, managing trancients and to reverse briefly, so that a triple strenghening thread can be put on any weak spots in the ribbon. Some power may also be needed to transfer from the double ribbon to the single ribbon at about 38,000 kilometers, where the ribbons are stationary with respect to each other. Operation will be somewhat simpler after the ribbon strenghing is complete. ie Two anchor ships are not needed unless something goes wrong. Most of the pay loads will not go higher than 38,000 kilometers.   Neil

Someone thought the orbital altitude should be 600 kilometers to 800 kilometers instead of the 400 kilometers I suggested. My guess is very cirular is also important to help keep the swarm evenly spaced. Does that reduce the Falcon payload to about 800 pounds?
I have not seen any design details. The solar panels should face the sun approximately, but the microwave transmitting yagi needs to be preceisly alligned with other antenas in the swarm, plus very precice phase lock.
A laser diode array, also needs extreem pointing accuracy to deliver the beam to the correct 100 square meters or less. Either way the illuminated spot needs to be much less than one square kilometer, or the energy received will not be at all impresssive. We can receive picowatts per square meter from Direct TV or Dish satelites at present, thoughout most of Colorado, USA.  Neil