LaserMotive Wins Space Elevator Competition

Speaking of contests, another interesting competition was held that I hadn't actually heard about until recently.

The Spaceward Foundation, for the past few years, has organized space elevator competitions inspired by the X-Prize for the past few years. The Space Elevator Competition actually has two different contests: one for tether strength, and one for climber speed and capabilities.

It is the climber contest we're interested in here. There have never been any winners until now, yet the competition has become more difficult every year. In order to win this year, a competitor must demonstrate a device that climbs a nearly kilometer-long tether hung by a helicopter at a speed of at least two meters per second using wireless power provided from the ground. A difficult feat to be sure!

Yet this year, we have a winner. LaserMotive successfully demonstrated this feat using a climber attached to a solar panel that collected energy from a ground laser. LaserMotive is primarily a company interested in developing remote power capabilities rather than doing space-oriented activities, but that is certainly one of the pieces of the puzzle needed to create a successful space elevator.

Trip to Space

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Solar Array

Progress: 6.47%  Power: 65W

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...

LASERS!!!

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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.

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Japaneese Company Announces Space Elevator

I know, I know, I'm way behind on space tourism news. I plan a flurry of posts in the next couple of days to catch up.

It seems the LiftPort Group has some competition! Another group, the Japan Space Elevator Association, has announced that it is in the initial stages of planning a space elevator.

The elevator's cables (presumably made of the same carbon nannotube material that the LiftPort Group plans) will rise out of the atmosphere and cross the 22,000 mile span to a satellite in geosynchronous orbit. The energy required to lift items into space using this telescope is anticipated to be as little as a hundredth of that required to launch a space shuttle. And they only plan to spend a trillion yen to build it.

I couldn't find a lot of information on the Japan Space Elevator Association itself; they don't have an official website that I could find. When I do find more information. I'll write up a full company profile.

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