Researchers have used the ancient Japanese art of paper folding to possibly solve a key challenge for outer space travel: how to store and move fuel to rocket engines. They developed an origami-inspired, folded plastic fuel bladder that doesn’t crack at super-cold temperatures and could someday be used to store and pump fuel.
The challenge of fuels management has been an important limiting factor in space travel, largely restricting space travel to either shorter trips for large amounts of cargo or to small satellites for long-duration missions. In the 1960s and 1970s, U.S. researchers tried to develop round balloons to store and pump liquid hydrogen fuel; however, the bladders would shatter or leak as they tried to squeeze it at the required very cold temperatures for the liquid fuels. The heartiest designs only lasted five cycles. Current systems use metal plates and the principle of surface tension to manage liquid fuels but the systems are slow and can only dribble out fuels in small quantities, so the size of fuel tanks and missions are limited.
In an origami-based bellows, the folds spread out stresses on the material, making it less likely to tear. Using a thin, Mylar plastic sheet, the team used the design to develop a fuel bladder. Once folded, the bladder was tested in liquid nitrogen at about 77 degrees Kelvin. The researchers found that the bladder can be squeezed at least 100 times without breaking or leaking under cold conditions. They’ve since demonstrated the bellows numerous times and it still doesn’t have holes in it.
The researchers are now beginning to conduct more rigorous testing. They plan to do testing with liquid hydrogen, assessing how well they can store and expel fuel and comparing the flow rates of their bladder with current systems.