Fuel economy…in a rocket?
Until now, all chemical rocket engines function essentially the same: spark off the reaction and hold on for dear life. You could redirect the thrust and, sometimes, turn it off entirely, however it was pretty much a light-switch type reaction. Although this certainly made it easy to calculate fuel use, it was also extremely inefficient. See, an engine must be capable of accelerating the rocket to escape velocity, and keeping it at, or above, that speed. Since our current rocket engines are only capable of accelerating, we have to calculate the exact break even point where the rocket runs out of fuel but has enough velocity to reach it's intended orbit. This means a lot of wasted fuel and problems if we miss our mark. It's basically like driving a car with only one gear, no brakes, and a throttle that is either open all the way, or completely closed. To get anywhere, you must accelerate to a point where you can just coast the rest of the way. Fortunately, that's all about to change. Some researchers at Georgia Tech have designed an new rocket engine that would be 40% more efficient, and be smaller, than what we have now. It's basically the equivalent of upgrading to a five gear transmission with full throttle control.
Curious? Read more here.