Improved Aerogel Vacuum Thermal Insulation

Lyndon B. Johnson Space Center

An improved design concept for aerogel vacuum thermal-insulation panels calls for multiple layers of aerogel sandwiched between layers of aluminized Mylar (or equivalent) poly(ethylene terephthalate), as depicted in the figure. This concept is applicable to both the rigid (brick) form and the flexible (blanket) form of aerogel vacuum thermal-insulation panels.

An Improved Aerogel Vacuum Insulation Panel contains multiple layers of aerogel interspersed with layers of aluminized poly(ethylene terephthalate). The panel is shown here in the uncompressed form at an intermediate stage of fabrication. Once the interior of the panel is evacuated, exterior atmospheric pressure squeezes the layers together.

Heretofore, the fabrication of a typical aerogel vacuum insulating panel has involved encapsulation of a single layer of aerogel in poly(ethylene terephthalate) and pumping of gases out of the aerogel-filled volume. A multilayer panel according to the improved design concept is fabricated in basically the same way: Multiple alternating layers of aerogel and aluminized poly(ethylene terephthalate) are assembled, then encapsulated in an outer layer of poly(ethylene terephthalate), and then the volume containing the multilayer structure is evacuated as in the single-layer case.

The multilayer concept makes it possible to reduce effective thermal conductivity of a panel below that of a comparable single-layer panel, without adding weight or incurring other performance penalties. Implementation of the multilayer concept is simple and relatively inexpensive, involving only a few additional fabrication steps to assemble the multiple layers prior to evacuation. For a panel of the blanket type, the multilayer concept, affords the additional advantage of reduced stiffness.

This work was done by Warren P. Ruemmele and Grant C. Bue of Johnson Space Center. MSC-24351-1