Advanced space propulsion systems are a critical need for future NASA deep space missions. High thrust or high Isp engines could revolutionize space exploration. Nuclear Thermal Propulsion ("NTP") is a high thrust/high Isp propulsion technology, with a demonstrated Isp ~850, twice that of chemical rockets. Zero boil off of LH2 propellant for long duration missions is among the critical technology advancements needed for NTP. Quest proposes to develop and test an innovative, high performance thermal insulation system, designed to provide high performance on large LH2 tanks. Cellular Load Responsive ("CLR") multilayer insulation integrates a mid-size cryopumping self-evacuating vacuum cell core with load bearing LRMLI within the compartments. CLR can offer a structural, high performance insulation system, that is damage tolerant, can support external loads such as thermal shields, and provides good thermal insulation both in-air (for ground and ascent phases) and in-vacuum (once in-space). CLR could provide 92% lower heat leak in-air during ground hold, and 97% lower heat leak in-space than SOFI. NASA's Technology Roadmaps call "Zero Boil Off storage of cryogenic propellants for long duration missions" and "Nuclear Thermal Propulsion components and systems" the #2 and #7 ranked technical challenge for future NASA missions. In this Phase I program, a CLRMLI system would be modeled, analyzed, designed, fabricated, installed on a cryotank, and tested for thermal performance for ground/ascent and in-space operation. CLRMLI could provide a robust SOFI replacement, with higher performance, lower mass, able to eliminate freezing/cryopumping of air components during ground and ascent stages. CLRMLI could help meet NASA's cryogenic fluid management requirements such as Zero Boil Off for cryogenic propellant storage and transfer.