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How to Advance the Development of Space
by Twenty Years


by Win Wenger, Ph.D.

#

Short of some anti-gravity device and technology that might never be found, the most elegant solution for getting people and payloads into space is the Space Elevator.

Counter-weighted from beyond the point of geosynchronous orbit, 22,000 miles out, the Space Elevator would use simple mechanical energy (or, more likely, the mass driver effect) simply to lift people and payloads up and down. A long ride, but arguably better than a high-gee ride atop some huge bomb of a rocket spewing costly reaction mass all over. A long but gentle ride all the way — riders will probably party all the way!

And more to the point, it would cost only 1% of what it costs per person or per pound with the present shuttle/rocket system even when that system is operating.

And, also more to the point:  operating a constant high volume of traffic up and down between space and ground, in contrast to the very occasional solitary missions of the shuttle even when it is running. With that high volume of traffic, unit costs would be way-y-y-y down!

But —

Alas, there is a slight hitch:

We are still years or decades away from being able to create materials strong enough. We can't make a cable that can support its own weight over such distances, much less the elevator apparatus that would have to be supported on it. It might be 20, 30, 40 years before we can create materials which are strong enough for that purpose.

But —

Here's a surprise:  We can have the Space Elevator up within 6-7 years — without need of such a super-super strong material for the cable! Here is how —

O

Supports along the way

The cable does not have to support all of its own enormous weight.

Most of the length of elevator cable can be supported at frequent intervals — thousand-mile intervals, hundred-mile intervals, or even much closer intervals — by solar sails. Most of the upper portions of the system can be more a tethered solar sail system than anything else, and the shorter intervals of cable do not have to be unusually strong in order to do their job.

Closer in to the Earth, where the Earth's shadow would fall for enough of each day to render solar sails useless, there may be an additional solution — temporary lift support by small, efficient rocket motors distributed along the length of the lower reaches, to maintain and sustain the mass driver track and to correct the temporary deformations which would necessarily accompany each launch.

If the efficiency of cesium ion drive can be improved, those little motors can go for years, and power can be supplied along the cable instead of the motors' having to be self-contained with their own more conventional fuel and power source.

The bottom thousand or so miles of cable and elevator system still have to be quite strong, but not nearly so strong as 40,000 or so miles would have to be. We already have, I'm given to understand, materials strong enough for this easier purpose. We don't have to wait twenty years or a century to have a working Space Elevator.

O

Elegance vs. having the system now

The original elevator scheme is elegant. This proposed version of it, alas, is not. Solar sails flopping around, supplementary engines station-keeping, arranged to redistribute and help support the load. Both sails and drive engines would have to be multiply redundant, replaced on an automatic rotation. (Most of that process, and most of the elevator's construction generally, could be done by computers and remote control.)

There would have to be redundant systems all over so that, even if sections of the elevator system were to fail, they won't cascade and, especially, that they won't cascade downward — that thousands of miles of cable with gravitational energy won't come crashing down on someone's head. Later, when we do develop strong enough materials, we can replace this jury-rigged space elevator with the elegant model.

But the elegant model is twenty or thirty or fifty years off while we wait for the superstrong material for cables to be developed. With this jury-rigged, patchwork elevator we can have a working space elevator within four to seven years.

Not only would we have very low unit costs per launch — in stark contrast to our space shuttle even on those rare occasions when it is operating - but we would have declining long-term cost curves, meaning that the more it was used, the more the costs of space development would further reduce. This would induce a huge increase and acceleration in the development of space. That would only continue and expand once we had the elegant version of the elevator — meanwhile, we'd have enjoyed thirty years or so of burgeoning space development to prosper from and with.

O

Comparison with our other proposed launch system

This proposed system has some nice advantages in common with our other proposed launch system, which none of the other launch systems proposed from elsewhere appear to enjoy.

  1. Power is mainly supplied externally, from the ground.
  2. We can use old technology sitting there on the shelf.
  3. The supporting launch track, through which power and moment are supplied, is in turn externally supported.
  4. Deformation and recovery occur with each launch as the track realigns by laser-sighted computers and motors.
  5. Unit costs are very low, and get lower the more one uses the system.

Until some basic engineering studies are run, this writer simply does not know which of the two systems — the elevator track supported from space, or the O'Neill mass driver track supported from the atmosphere by balloons tethered from the ground — will be less expensive to build. We would appreciate input on this. But it'd be nice indeed to have in 4 to 5 years the kind and degree of space development which otherwise we'd have to wait many decades for.

Comments welcome.
 

Related Space Science Reading

O

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Win Wenger


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