Monday, December 29, 2008

More problems with the Space Elevator?

The concept of the Space Elevator has plenty of problems; nobody is denying it. Not the least of these problems is the fact that technology needed to manufacture the necessary carbon nanotube ribbons hasn't been invented yet There are also the issues of avoiding storms in the vicinity of the ribbon, providing power to the elevator during its ascent, and how the heck do you launch a satellite tethered to the ground without destroying the tether during launch?

Well, a new study presents a new problem; the Coriolis effect could throw the satellite off-course during the elevator's ascent. Yep, the Coriolis effect. The same effect that makes Canadian toilet water spin one way and Australian toilet water spin the other is going to pose an issue to any potential space elevator.

Because the ribbon tethering the satellite to the ground will be flexible and not rigid, the Coriolis effect will drag a single rising elevator in the opposite direction to the Earth's spin, causing the satellite at the end of the ribbon to be pulled off-course.

Don't understand why this would occur? There's a simple experiment you can perform. Put a large bead on a strong string, and make sure the bead will slide easily along the string. Tie the string to the edge of a merry-go-round and sit in the middle, holding tightly on to the other end of the string so that it is straight. As the merry-go-round is spinning, throw the bead out along the string away from you. You'll notice that as the bead gets closer to the edge of the merry-go-round, it will pull the string in the direction opposite to the spin. This is the same effect.

However, all is not lost; the study proposes a few potential solutions to this problem. The simplest of these is that the elevator would need to ascend incredibly slowly to minimize the effect. However, any elevator ascending at the necessary speed would take over three weeks to arrive at its destination.

Cool Science Fact 1: To say that slowing the elevator would "minimize" the Coriolis effect is an oversimplification; in reality, moving the elevator slowly would allow it time to slow down the Earth's spin, stealing enough energy from the earth's spin so that the effect isn't readily apparent.

Most of the other potential solutions involve various methods of coordinating the ascent and descent of multiple climbers to cancel out the effect. Many of these require two or more ribbons, but that seems likely anyway. Having two ribbons attached to the same satellite is a lot more economical than just one, and anyone who knows anything about space travel knows that you don't send anything into space without a backup.

So all in all, it's a problem, but one that is likely to be easier to overcome than the issue of manufacturing twenty-thousand-mile sub-microscopic tubes of linked carbon atoms.

Progress: 4.03%  Flight Time: 0:06:05

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