Description: Current cryogenic insulation materials suffer from various drawbacks including high cost and weight, lack of structural or load-bearing capability, fabrication complexity, and property anisotropy. A need clearly exists for lightweight thermal insulation that is isotropic and structurally capable with high thermal performance, while also offering reduced fabrication and installation complexity and lower cost. In previous work for NASA and DoD involving lightweight structural insulation for high temperature engine and airframe applications, Ultramet developed and demonstrated lightweight open-cell foam insulators composed of a carbon or ceramic structural foam skeleton filled with a low-cost, nanoscale aerogel insulator. The potential exists to adapt and optimize aerogel-filled structural foam for the cryogenic insulation application, taking advantage of the thermal and mechanical benefits of each component while offering low cost and manufacturability in complex shapes. In Phase I, the feasibility of fabricating aerogel-filled open-cell foam for cryogenic application was demonstrated, initial thermal performance was established, and a path for continued material and structural optimization was developed through design and modeling. In Phase II, Ultramet will again team with Ocellus, a leader in low-cost aerogel fabrication, and Materials Research and Design for design and analysis support. Thermal performance will be characterized at the Cryogenics Test Laboratory at Kennedy Space Center.

Benefits: Advanced cryogenic insulation will find extensive commercial application as cryogenic liquids (nitrogen, oxygen, argon, carbon dioxide, and liquefied natural gas) must be stored, handled, and transferred in support of the food, transportation, energy, and medical industries. To minimize heat leaks into storage tanks and transfer lines, high-performance, economical materials are needed to provide high levels of thermal isolation and minimize evaporation losses. Specific applications for these industries include energy (electricity, power transmission, and fuel cells), food (preservation and packaging), medicine (biological storage), electronics (imaging and semiconductors), and scientific research instrumentation.

The potential application of this technology as a lightweight structural insulator for cryogenic propellant tanks and lines both at ambient pressure and under high vacuum may prove an enabling technology for future NASA space and planetary missions and ground operations. Passive thermal control is required for zero-boiloff storage of cryogens for both long term (>200 days for liquid oxygen and hydrogen) on the lunar surface and short term (14 days) on orbit. Future launch sites on Earth and in space will need a new approach for supplying propellants, gases, and electrical power. Insulation advances must be built around system-integrated concepts for both energy conservation and cryogenic production. Piping networks to deliver the cryogenic fluids across long distances will be a key element, and cost-efficient production and storage of cryogens is an important area of future NASA technology development. The proposed aerogel-filled structural foam cryogenic insulation will offer improved thermal performance over current materials, with the added benefits of reduced weight and fabrication and installation costs relative to conventional multilayer insulation.