In addition to the temperature and pressure cycling, the larger tank will receive mechanical loads testing at Marshall designed to simulate the shear and moment acting on fuel tanks in flight. “It would be multiple pressurization and cryogenic thermal cycles as well as multiple mechanical loads, all those in combinations,” Vickers says. “Our objective is to prove that the tank can both contain hydrogen without leakage or permeation and that it can sustain the mechanical loads of launch.”
The work is being done under the NASA technology-development organization's effort to generate “game-changing” technologies. The agency already plans to use composite fuel tanks in the cryogenic upper stage it needs to develop to help increase the capability of the heavy-lift Space Launch System to 130 metric tons from 70.
While work on that stage is just beginning, Vickers says the composite tanks can be retrofitted into existing launch vehicles, passing the weight savings along directly to increase payload capacity. That is attracting attention in the launch-vehicle industry as new players like SpaceX and Blue Origin crank up the competition.
“There is a lot of excitement about this technology,” he says. “We are being approached by other organizations—government and industry—to transition this technology to their products.”
Within Boeing, too, interest is growing, says Rivera. “We're getting very similar interest from our unmanned systems, space systems and advanced space systems units,” he says. “We're working closely with them to provide the information they need so they can include composite cryotanks in their trade studies.”