re: MacChine  12-29-05: Throwing nueclear waste at the sun requires more energy than one would think. Earth orbits the sun at about 50 kilometers per second. Even an over length SE flips payloads at less than 15 kilometers per second (with respect to Earth) which can subtract from the 50, if the payload is flipped about midnight, I think. Lot's more delta v is needed to hit the sun instead of doing a gravity asssist manuver around the sun. I don't think the Sun would respond, detectably, if we dumped the entire inventory of nuclear waste into the Sun in the same second, but getting it to hit the sun is too costly, plus the possibility of something going wrong.  Neil

A length of ribbon beyond the counter weight may be an excellent idea, but hundreds of kilometers (instead of thousands) is likely enough to get a good crack the whip effect which can send the payload faster and in a significantly different direction. A winch at the counterweight could fine tune the crack the whip, but my guess is fine tuning the counter weight will typically be done by dumping some of the counterweight into solar orbit, and/or moving some of the retired climbers either in or out on the ribbon.   Neil

If Modavis is correct,"the strengthening threads need to be applied at full tension" 1 we will have to stop laying thread during trancients that reduce the tension 2 Slight defects are likely to break the ribbon if it near max alowable tension during thread laying.   Neil

The dead head problem may be minor as the sea anchor will have a staff of several who will want to take leave occasionally and the anchor base will likely be a tourist attraction, plus an occasional consultant, scientest and dignitary.   Neil

My guess is Jallison has the details correct. Is there any chance that a high temperature ceramic binder can be developed, or the carbon/carbon bond that someone mentioned on another thread?
In the presence of oxygen the ribbon will burn up like charcoal or graphite, if heated to more than about 500 degrees c = 932 f.
CNT can't burn, if there is no oxygen, chlorine, nor a few other chemicals than attack hot carbon. Does anyone know the temperature at which CNT begins to revert to amorphous carbon which has little strength?   Neil

I have no opinion on most of this, except the anchor at sea will likely have several kilometers of ribbon in a reel/winch, so slippage will not be a problem unless friction is zero. Zero friction, if it occurs, may not allow the climbers to move by pinching the ribbon between rollars.
I would like to see a bonding material that can tolerate temperatures in excess of 1000 degrees c as I suspect the nano tubes are very temperature tolerant in a very high vacuum.   Neil

Hi temlakos: If the first 20 ton SE is semi successful, I think the concept can be scalled up to 100 tons or more. I agree, speed at release is sufficient to go anywhere in the inner solar system. unless the SE is shorter than 91,000 kilometers. Only minor mid course correction and destation manuvering requires a small propulsion system and small amount of fuel. A 130,000 kilometer SE can likely reach Jupiter or Saturn, in a few years, then do a sling shot manuver.
My guess is oscillations/transients can flip the pay load in at least a slightly different direction, but timing will be critical.  Neil

If the inside dimensions of the passenger cab are a cube 2.2 meter on an edge with the corners and edges rounded slightly, 6 people sitting plus two laying down would be comfortable.
Only one could stand up and pace a bit. A small conversion van size toilet and shower would take up part of the passenger cabin. Food storage, food preparation and life support could be wholly or mostly outside the passenger space, along with some small cargo space, if the transcient conditions allowed cargo for this particular launch.
The ribbon needs to pass though the center of the cab for the stress on the ribbon to be balanced, but the ribbon shieth only needs to be one or two cm thick as the ribbon has almost no thickness. Some cargo is desirable as the passenger movements will be swamped out, if no one passenger is more than 2% of the gross weight of the elevator car. The cargo also reduces the radiation exposure to about double that of a typical commercial jet, provided the car returns to the Earth after climbing to an altitude of about 100 kilometers. That is one hour round trip if the car averages 200 kilometers per hour. It likely is not practical to carry cargo, unless it can be left at a way station at 100 kilometer altitude. Passengers would travel on even days and cargo on odd days of the month. The above are my wild guess, so please comment, refute or embellish.   Neil

Since the tallest towers built so far are about one kilometers, 3000 kilometers would take centuries if we double the heigth each decade. It is prudent to add only about 10% to the previous tallest success. More than double would be total folly in the minds of most contractors. Optimistic projections for CNT may be a ten kilometers tower, even if cost is no object.
I don't think the tower would halve the total mass of the ribbon. Can you explain 150 times? The tower may have 150 times the mass of the slightly shorter ribbon. You may be thinking taper backwards: the massive portion of the tether is near GEO altitude. Don't tall buildings such as the World Trade Center have dozens of  reinfoced concrete pillers exceeding one square meter near the bottom/not sufficient to save the structure from a very hot fire? The ribbon will have a cross section of much less than one square centimeter!   Neil

364,000 kilometers tall may be possible for the SE anchored on Earth's surface, but the limits of CNT would be pushed as counterweight would be required on the Earth side of GEO altitude, or there would be very high tension at the Earth's surface anchor.   Neil

Perhaps several miles under favorable conditions. The CNT is black, 1 meter wide, so it will not reflect light, but might be visable against a white cloud or blue sky background. The sky is black day and night above about 30 kilometers. The coating that protects from atomic oxygen will likely increase visability. In any case it may be more visable at some infrared wavelengths.  Neil

It is generally agreed that tether fragments are invisible more than a mile away. Electrically conductive tethers should be trackable with specially designed RADAR, but non-conductive tethers will not be trackable, I think, unless the fragment has a transponder, beacon or other radio device.
Is anyone of the opinion that tin snips, scissors or simular will cut 100 nano meter thick CNT ribbon?   Neil

It is generally agreed that tether fragments are invisable more than a mile away. Electrically conductive tethers should be trackable with specially designed RADAR, but non-conductive treathers will be untrackable,I think, unless the frament has a transponder, beacon or other radio device.
Is anyone of the opinion that tin snips, sissors or simular will cut 100 nano meter thick CNT ribbon?   Neil

With a counterweight, it appears that 100,000 kilometers is long enough for a moon space elevator which passes though L1, so tangling is not a problem unless we design both for much longer. The moon elevator would be useful to travel from moon to L1 and return, but the tip speed would be  too low for most other uses, except a sling shot manuever around Earth.   Neil

Hi MACchine: Some of us analyzed the www.skypower.com web site earlier this year and concluded they were exaggerating. It may, however, be adequate to support all the SE weight below 30 kilometers, most of the time, plus supply electricity half of the time. The ribbon above would get stretched as the 30 kilometer station drifted lower, but the lift would all but surely be restored before serious damage occurred to the space elevator, or the 30 kilometer station. I have been saying the stretch transient propagates up the ribbon at about 500 kilometers per hour = 200 hours to reach the top. At least one person suggested 7 kilometers per second = 25,200 kilometers per hour = 4 hours to the top. There are several types of transcients that will travel on the ribbon, perhaps at different speeds. Can someone clarify?   Neil