Load Responsive MLI: Thermal Insulation with High In-Atmosphere and On-Orbit Performance, Phase II

Lightweight, high performance thermal insulation is critical to NASA's next generation Exploration spacecraft. Zero or low cryogenic propellant boiloff is required during extended missions and lengthy on-orbit times. Heat flow through multilayer insulation is usually the largest heat leak in cryogenic systems, so improvements are desirable. Load Responsive Multi-Layer Insulation (LRMLI) is an innovative new technology using micro-molded polymer dynamic spacers that provide high performance insulation both in-atmosphere and on-orbit. LRMLI under atmospheric pressure compresses dynamic spacers to support an integrated, thin vacuum shell for high performance in-atmosphere operation, and disconnects the spacers during on-orbit/lunar surface operation to reduce heat leak and provide ultra-high performance thermal insulation. LRMLI was successfully proven feasible in Phase I work, reaching TRL4. A LRMLI prototype was built and tested and a 3-layer, 0.25" thick blanket demonstrated 7.1 W/m2 (0.19 mW/m-K) heat leak for on-orbit and 14.3 W/m2 (0.34 mW/m-K) for in-atmosphere operation. Equal heat leak on-orbit of a 0.25" LRMLI blanket (2.1 kg/m2) would require 16" of SOFI (15 kg/m2), with LRMLI having a 64X advantage in thickness and a 7X advantage in mass. LRMLI insulation can provide superior cryogen insulation during ground hold, launch and on-orbit/vacuum conditions without need for purge. Total heat gain into cryogenic systems could be substantially reduced. Terrestrial non-NASA applications include LH2 powered aircraft and cars in development. This proposal is to further develop LRMLI toward commercialization. Tasks proposed include a study of both NASA& non-NASA applications to select two for further optimization, next generation design of dynamic spacers and modular vacuum shells, and building and testing prototypes in realistic environments such as a 3' diameter cryotank similar to a selected use like NASA Altair or Boeing HALE tanks.