Flexible Reusable Surface Insulation Blankets
AFRSI blankets replace the
vast majority of the LRSI tiles. AFRSI consists of a low-density
fibrous silica batting that is made up of high-purity silica and
99.8-percent amorphous silica fibers (1 to 2 mils thick). This
batting is sandwiched between an outer woven silica high-temperature
fabric and an inner woven glass lower temperature fabric. After
the composite is sewn with silica thread, it has a quiltlike appearance.
The AFRSI blankets are coated with a ceramic collodial silica
and high-purity silica fibers (referred to as C-9) that provide
endurance. The AFRSI composite density is approximately 8 to 9
pounds per cubic foot and varies in thickness from 0.45 to 0.95
inch. The thickness is determined by the heat load the blanket
encounters during entry. The blankets are cut to the planform
shape required and bonded directly to the orbiter by RTV silicon
adhesive 0.20 inch thick. The very thin glue line reduces weight
and minimizes the thermal expansion during temperature changes.
The sewn quilted fabric blanket is manufactured by Rockwell in
3- by 3-foot squares of the proper thickness. The direct application
of the blankets to the orbiter results in weight reduction, improved
producibility and durability, reduced fabrication and installation
cost, and reduced installation schedule time.