HopDavid wrote:
Well, it's only 1/4 the length of the Great Wall of China. But it's about 100 times taller than Burj Khalifa, the world's tallest building. Sorry, not plausible.
Look at the website (
http://launchloop.com
), read the paper, do the math. If it still isn't plausible to you, I would love to hear an informed opinion why. But if your reason is "it doesn't resemble stuff I already know about", then it would help to learn about the history of engineering, and be amazed at what technological imagination can make possible.
Before it was built, the Great Wall of China was implausible. The 828 meter Burj Khalifa, with construction started in 2004, would have been implausible in 1904, when the world's tallest building was the Philadelphia City Hall at 167 meters. All are compression structures.
But compression is not the only way to hold stuff up - consider the airplane, which is a structure held up by deflected mass. A stream of airplanes, nose to tail, takeoff to landing, could be made into a very strange, very tall structure. One of the taller "structures" of recent times was the helicopter and 1 km tether that Ben Shelef arranged for the 2009 space elevator games, which my friend Jordin Kare won with his multi-kilowatt laser.
The launch loop is a "dynamic structure". One example of a dynamic structure is a firehose stiffened by moving water. Fast moving water can hold the hose up many meters, while the same water, uncontained and unmoving, forms a shallow puddle. The launch loop contains a stream of iron moving very fast, supporting a narrow (10 cm diameter) vacuum enclosure with actively controlled magnets. Seems crazy until you do the math. But then, the New York Times couldn't do the math in 1920 when it claimed Goddard's rockets needed something to push against.
Here's an amusing small scale demo of a dynamic structure by a student in Virginia.
http://launchloop.com/EugeneKovalenko
. His loop rose only about a meter, but at 1:80000 scale, it is closer to a practical launch loop than Ben's kilometer tether is to a space elevator with a 100,000km counterweight. Eugene got all the pieces at Home Depot (and rented the motor tool). Somewhat cheaper than Ben's multimillion dollar setup.
The Curiosity landing was one of the most implausible things I've ever witnessed. But those amazing engineers at JPL did the math. The machine did, on Mars, what the calculations did in the computer years before. Launch loop will certainly be more of a challenge than Curiosity, and will rest on an equally long string of incremental accomplishments by many people over a long time. But Curiosity's story began in that field in Auburn Massachusetts in 1925, in von Neumann's Maniac computer, in Noyce's planar integrated circuit, and in many other observations, speculations, experiments, and inventions. You might not find any of those plausible before they happened, but all resulted from hard work motivated by knowledge and imagination.
Russian schoolteacher Konstantin Tsiolkovsky dreamed of many things like Curiosity in his log cabin in Kaluga - we can only hope we can be as creative and forward looking. It is OK to dream, to be unreasonable, to use you mind to see things that others haven't noticed yet. Then start analyzing and building. The way to predict the future is to invent it.
Statistics: Posted by keithl — Sun Aug 19, 2012 5:43 am UTC