Friday, May 13, 2011

New Scientist: Beam Riders

The dream of making space commercially attractive has been on the minds of many investors over the years. Space hotels, mining operations on the moon, all of it can become economically viable if lasers and microwaves come into action. Usually it takes a large amount of oxidant and fuel to bring a rocket to escape velocity thus increasing the costs ten-fold. And the cost per kilo of cargo is enormous over 10k dollars. In order to reduce these costs beamed propulsion is the key.

Two different theories have been developed and even put into practice small scale to solve this problem. The first one involves a heat exchanger which uses microwaves or lasers to trap their energy. This is then converted to kinetic energy as the hydrogen atoms inside the tank expand rapidly and escape through the exhaust. By using this method the speed of the rocket increases exponentially(from 4400 meters per second to 7000) and the weight decreases as well. The best of both worlds. However there are still some disadvantages to this particular method. Any beam is diffracted by air as the distance from the source increases. The longer the wavelength the worse the effect. To counteract this the wavelength must be very small and the dish used for the laser very large.

The second way is to use a "lightcraft" that is much much smaller than all types of rockets and creates a plasma of superheated plasma to fly. The trick of this vessel is that it uses the surrounding air as fuel as it travels only requiring an internal fuel tank for its last jump. I won't go into much more detail because I don't understand some of it myself, so let's just say that both require ground laser to function.

As we can see the amounts of new ideas and theories that surround our world is enormous. Whoever said that the modern age is a stagnant age should really read this article and reflect on their opinion. And our dreams of sending our children to space may not be so far away as we think.