Description: GTL has already made substantial progress in developing and validating the BHLTM technology for application to cryotanks. Earlier coupon testing of the temperature-dependent material properties confirmed the potential of the BHL technology to eliminate the microcracking issue. This was followed by the fabrication and cryo-pressure cycle testing of small BHL cylinders. No laminate leaks or degradation were detected in a test with more than 40 cryo-pressure cycles. While other efforts are exploring the reliability aspects of the BHL technology at larger scales, the proposed effort will focus on evaluating the long-term cryogenic propellant storage capabilities of the BHL technology. Specifically, this effort will include initial tests to examine the implications of long-term oxygen exposure on the BHL laminate as the first step towards validating the technology for long-term NASA exploration and other missions. The effort will also refine the BHL laminate design to optimize it for long-term cryogenic propellant storage. This will include an effort to increase the insulating capability of the structural laminate to minimize the need for secondary insulation. A small BHL cylinder shall be fabricated using these refinements as a proof-of-concept.

Benefits: The cryotank technical barriers are essentially the same for NASA and Non-NASA applications. The proposed BHL cryotank technology directly addresses these issues and will provide the marketplace with access to high-performance, reusability and reliable cryotanks. These cryotanks can be used to enhance the capabilities of traditional DoD and commercial spacecraft, rockets and launch vehicles. This technology could be critical for commercial space tourism by providing affordable robust capabilities that are beyond the current state of the art.

The high strength to weight of modern composite materials offers the potential for substantial performance gains compared to traditional structural and pressure vessel approaches. These weight savings will be especially critical to meet the high performance requirements of future NASA exploration systems, including heavy lift launch vehicles, Earth departure stages, lunar or asteroid descent vehicles, and long-term propellant storage in space, on the Moon or on Mars. While the use of composite materials is fairly mature when it comes to non-wetted structures, there have been substantial technical barriers that have slowed the application of this technology to propellant storage. These barriers are most evident in attempts to apply composite technology in cryotanks for cryogenic propellant storage, which is a critical need for NASA exploration systems. The BHL technology addresses these issues and offers high-performance, reusability and reliable cryotanks for future NASA missions.