The fuel tanks responsible for launching rockets into space have been metal for decades. Launching a rocket is not a gentle feat, and space is not exactly the friendliest environment either. Metal deals with the conditions well, but it is has a major downside. Weight.
It costs in the thousands of dollars per pound to get materials into space, so composites hold some definite promise. However, these fuel tanks are not the puny things you might find in your car or on a bus, or anything on the road. The proposed tank is 18 feet in diameter. That scale requires some clever processing.
To accomplish the gargantuan creation, NASA and Boeing engineers teamed up to meet the challenge. The Dreamliner is proof positive that Boeing knows a little something about composites, and NASA certainly knows a little something about space exploration.
The fuel tank must withstand extreme conditions of temperature and pressure. The tank will be tested under these conditions to determine suitability. The fuel is liquid (cryogenic) hydrogen which boils at a balmy 20.271 K (−252.879 °C or −423.182 °F).
Hydrogen, being such a small atom (or more often diatomic molecule), it is also difficult to prevent it from diffusing or otherwise leaking. The tank development involved new approaches to laying up the carbon fiber which do not require an autoclave and new materials as well. The project has required concurrent innovation in many areas to achieve the desired results.
The tank was just finished at Boeing’s Developmental Center in Washington State and will be moved to NASA’s Marshall Space Flight Center in Alabama for testing this Summer. The 18 foot diameter tank is comparable to current, metallic versions, but was preceded by promising results from a smaller 8 foot diameter tank.
The engineers are hoping their hard work will be paying dividends in the not-too-distant future. The design is expected to be cheaper and better, with a 30 percent reduction in weight and a 25 percent cost savings over the current state-of-the-art competitors.
Although composites have been in use throughout the space program, extensions to major components such as fuel tanks are showing there is still room for improvement. That improvement has only been made possible through new materials and manufacturing.
The video below shows some of the manufacturing process.
Images courtesy of NASA