Tuesday, January 6, 2009

Can a Space Elevator be Powered Mechanically?

Every once in a while, someone comes up with an idea so simple and obvious, yet so revolutionary, it's akin to inventing the wheel in 1950. Yesterday was one of those days.

One of the main problems with the creation of the space elevator is how to power the lifter. It would be impossible with current technology (or even with technologies under development) to give the lifter enough batteries or generator fuel to power its climb. The batteries or fuel simply wouldn't have enough power to lift their own weight 20,000 miles. So up until now, the main ideas have been to power the lifter with lasers or microwaves beamed from earth, which are technologies under development that could potentially work. However, those ideas come with various significant health and safety risks, and nobody is sure that either of the technologies will be there anytime soon.

Then this video came out yesterday. Age-Raymond Rice, a ground station engineer for the ESA, took a broomstick, an electric sander, and some hair brushes, and demonstrated a startlingly, disgustingly simple method to mechanically power a space elevator. You can view a video in the BBC article on this.

Basically, he strapped the hairbrushes to the broomstick with the bristles pointed down. This made it more difficult for the brushes to move down than up. Then he vibrated the broomstick using the sander. When the broomstick was jerked down, the brushes climbed up. When the broomstick was jerked up, the brushes stayed put. This caused the brushes to slowly rise along the broomstick using purely mechanical power.

A number of obstacles would need to be overcome to apply this technique to a space elevator. You would need a suspension system to keep the occupants and cargo inside the elevator from being shaken apart. You would need a way to ensure the jerking on the tether wouldn't tug the satellite off course. You would need to design a lifter that would remain balanced on either side of the tether (despite the movement of its occupants) to avoid rotational motion of the lifter caused by the jerking. Finally, you would need to design a system to ensure that the lifter's version of the hairbrush bristles and the constant jerking do not damage the tether.

However, these obstacles seem much simpler to overcome than designing lasers to power the lifter without the risk of kersploding it. Not that I'm against using lasers for anything and everything...


Progress: 4.03%  Flight Time: 0:06:05


Tony said...

How does this solve the power storage problem?

Joe Space Tourist said...

Well, most of the power needed by the lifter (using the old model) is to actually lift it. If it doesn't need to lift its own weight, all it needs power for is life support, lights, transmitters, and the like. That's a much easier task that can be handled by the same battery technology they use on the space shuttle.