Currently they’re just trying to get a concept of how a space elevator climber would work, but maybe it would be a lot easier if they don’t try to make one climber that can make it all the way, but have multiple smaller climbers. Rather than one climber that can carry a ton and makes a round trip every 10 days, have 5 climbers that can carry 400 pounds each and make a round trip over a portion of the cable every 2 days. There simply needs to be a mechanism to transfer the load between climbers.

An added benefit is that each climber can be optimized for a different part of the cable. For example, the low altitude climber might benefit from streamlined aerodynamics, or might have sails to take advantage of wind power to get a boost or use lighter than air features for buoyancy. The climbers going through the Van Allen radiation belts would have better shielding, but I assume that at least some ranges of the cable could be traversed with lighter shielding, so having shielding on one or two of the 1/5th size climber would be lighter than having the equivalent shielding on one large climber and not have it actually be needed for much of the journey. There might be a similar principle in regard to impact shielding for zones with lots of space junk. The climber traversing through “cleaner” regions might have large, more delicate solar panels.

One design possibility for the space elevator is to use a tapered cable, allowing its construction with weaker materials. But a tapered cable makes the design of the climber more difficult. As an intermediate version, if the cable had 5 different thicknesses over its length, each one could be serviced by a different climber designed for that section of cable. In that case the climbers would need to be designed so that one climber could carry another climber, either as one piece or possibly in multiple pieces to be assembled at the transition point between the cable types. If a climber needed maintenance or replacement, the lower climbers could carry it back down.

Of course 5 is a completely arbitrary number. The actual number would be determined based on the actual challenges that are out there and the distance that each challenge is in effect. Also, if the system to transfer loads involves a procedure with a checklist that takes an hour to accomplish, the number of climber regions would ideally be minimized, but if load transfer could happen mostly automatically in just a couple minutes, then a larger number of climbers would be reasonable.

One unfixable downside is that this does reduce the size of the maximum possible single object. Large objects would need to be brought up in pieces and assembled
-- scad mientist, Aug 02 2012

[+] nice, though there's a vague pulling at my mental coat-tails that says half-baked in a SF story.
-- FlyingToaster, Aug 02 2012


Ah, preheated possibly? Rings no bells with me though. And imagine the union work rules at the cargo exchange points, staggered like so many truck stops on a rope (+).
-- normzone, Aug 02 2012


Is it really a problem to make a machine that can climb a few hundred miles of string? Why?
-- MaxwellBuchanan, Aug 02 2012


//a few hundred miles// sp. "twenty-two thousand miles"
-- FlyingToaster, Aug 02 2012


OK - is it really a problem to make a machine that can climb twenty-two thousand miles of string? Why?

A quick calculation shows that the Guatemalan narrow-backed frog, which feeds at night on the ground, but roosts in the upper forest canopy by day, climbs about 20-30,000 miles during its lifetime. Clearly, then, we need to work on developing pressure suits and backpacks for these guys.

In any event, the climbers will need uniforms or nobody will know they're official.
-- MaxwellBuchanan, Aug 02 2012


or frogs.

Actually I'm surprised that all of the DARPA contestants used plain old friction; I'da expected magnetism to be in there somewhere (it was an aluminium cable, no?)

Anyways, if you have one piece of 22kilomile string, why not have 9 or 10 so you can carry a nice chunk of weight.

I like the staged idea though: platforms for resting and taking photos of the ride up, etc.
-- FlyingToaster, Aug 02 2012



random, halfbakery