ESA has made a breakthrough in its Future Launchers Preparatory Program, finding that carbon fiber reinforced plastic tanks are viable for rockets. The new work builds on earlier studies and has demonstrated a new design for a small-scale tank made of unique carbon fiber reinforced plastic (CFRP). The material is leakproof when used with liquid hydrogen and is also compatible with liquid oxygen without using a metal liner.
Project researchers note that a tank made completely of CFRP is significantly lighter than metal tanks and is faster and cheaper to build. The new tank is such a breakthrough because storing cryogenic propellants like liquid oxygen and liquid hydrogen requires tanks featuring metallic liners to make them leakproof with or without a composite overwrap.
The reason the metallic liners are required is because the propellants are cooled to -253 degrees Celsius. Fuel storage tanks are critical elements of the propulsion system, and the research provides proof that a high-performance pressure tank made from CFRP can withstand cryogenic stress. Researchers believe that future use of CFRP high-performance tanks would enable safer rocket launches while offering significantly lower mass than metallic tanks.
Constructing rockets using lower mass components that allow the rocket to produce the same thrust means higher payload capacity. Researchers say they discovered a very specific carbon composite and processing method allowing them to consider new architectures and combinations of functions to create upper stages not possible using metal.
Constructing the CFRP tanks to be leakproof required a complicated weave of black carbon fiber and a special resin. The material resisted extremely cold cryogenic temperatures, pressure cycles, and reactive substances over a number of separate tests. Additional tests with integrated thermal protection will soon be conducted with data from testing used to develop a full-scale demonstrator.