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Load Responsive MLI

Load Responsive MLI (LRMLI) uses a dynamic spacer and a modular, lightweight vacuum shell to withstand atmospheric loads. LRMLI provides both high thermal performance in-air, and ultra-high performance on-orbit. LRMLI is a SOFI replacement system with substantially higher performance. The LRMLI system is the most durable product in the next generation MLI product family. LRMLI is ideal insulation for LH2-tanks with in-air operation.

Load Responsive MultiLayer Insulation (LRMLI) is an advanced thermal insulation system that uses dynamic beam discrete spacers that provide high thermal performance both in-air and on-orbit. LRMLI may provide novel insulation systems with unique properties, including higher in-air performance than competing insulations such as SOFI or aerogels, with less thickness and less mass for equal heat leak, robust, high strength structure that can self support thin, flexible vacuum shells, support high strength ballistic layers for micrometeoroid protection, or support vapor cooled shields for advanced zero boil-off cryogenic storage systems.

In this Phase II program a next generation LRMLI system was designed, prototypes built, and structurally and thermally tested. Improved performance over the LRMLI prototypes was obtained, much knowledge of how to design and install LRMLI on cryotanks was gained, and LRMLI technology was reduced to practice on larger cryotanks. LRMLI prototypes (3 layers, 0.63cm thick, 77K cold, 295K hot) had an in-air heat flux of 29.3 W/m2, and an in-vacuum heat flux of 4.83 W/m2.

In-air LRMLI has a 24X advantage over Spray On Foam Insulation (SOFI) in heat flux per thickness and a 22X advantage over aerogel. On-orbit LRMLI has a 144X lower heat flux than SOFI per thickness and 8X lower heat flux than aerogel.

Load Responsive MLIIn the Phase II program significant progress was made in several key aspects of LRMLI technology. LRMLI uses a novel, proprietary and patented discrete spacer that provides both low thermal conductance and the ability to support over 90psi when loaded but disconnect when unloaded (external load). LRMLI insulation structures use a modular, flexible thin vacuum shell that allows the insulation to maintain an internal high vacuum while minimizing system mass.

LRMLI prototypes were successfully built, installed and tested on 20L cryotanks, then mixed LRMLI/Integrated MLI systems were built and tested, and finally LRMLI was installed and tested on a more complex 400L cylindrical/hemispherical cryotank, reaching TRL5.

LRMLI is an advanced thermal insulation system that has been successfully demonstrated in the relevant environment of mid-scale cryotanks. It offers substantially higher thermal performance than SOFI, and may be an excellent SOFI replacement for cryogenic fueled launch vehicles, for insulating orbital fuel depots with advanced vapor cooled shield zero boil-off design, and for cryogenic insulation in-air applications.

Highlights:

  • Load Responsive MLI dynamically connects spacers self supporting an integrated vacuum shell.
  • Modular LRMLI insulation structure with a thin, flexible, modular vacuum shell has been successfully designed, built and tested.
  • LRMLI offers unique thermal performance characteristics of high thermal performance in-air and ultra high thermal performance on-orbit
  • LRMLI is structurally very robust, able to self support over 90 lbs per square inch load
  • LRMLI can self support integrated Vapor Cooled Shields
  • LRMLI has higher thermal performance than SOFI or aerogels for insulating cryogens.
  • LRMLI in-vacuum has 144x lower heat flux than SOFI per thickness, with a 13x mass advantage
  • LRMLI in-air has 24x lower heat flux than SOFI with 2x lower mass.
  • LRMLI in-vacuum has 8x lower heat flux than aerogel per thickness with 2.8x less mass.
  • LRMLI in-air has 22x lower heat flux than aerogel per thickness with 7x lower mass.

 

Load Responsive MLI