Rocket fuel tank
Automobile fuel is in a tank, exiting towards the engine through a pipeline at its lowest point – gravity ensures that you will be able to use every last drop. In space it is more complicated because, whether liquid or gaseous, fuel tends to spread throughout the tank, as there is not enough gravity to pull it in any direction. The outlet used today consists of movable metal plates, which close as fuel is used. It has worked, but far from ideal, with serious constraints for very small or very large ships. And tanks in the shape of inflatable balloons never worked satisfactorily, tearing up very quickly.
Kjell Westra and his colleagues at the University of Washington, USA, say they have now found the definitive solution to this problem. They created a fuel tank for spacecraft using the Japanese folding technique, called origami, applied to a high-strength industrial plastic.
Origami bellows
Interestingly, while the fuel balloons tend to tear, the origami folds spread stresses in the material, making it less likely to tear. Simple as that, with no need for disruptive innovation. “The best solutions are those that are already ready and that you can transfer to what you’re working on,” recognizes Westra. After folding the plastic following instructions in a video he saw on Youtube, the researcher tested it in liquid nitrogen , at -196 ºC. The fuel bladder can be compressed at least 100 times without breaking or leaking, even in the extreme cold. And because it works like a bellows, it can expel every last breath of fuel. The researcher is now starting to conduct more rigorous tests and is preparing to do tests with liquid hydrogen (-253 ° C), in addition to comparing the flow rates of his bladder with current systems.
