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Name: AFRSI-2500 Blanket
Database: NASA Ames Thermal Protection Materials
Category: Silicon-Based Reusable Composites: Composite Flexible Blankets
Composition: extel 440 outer fabric, Saffil alumina insulation, and S-glass inner fabric, sewn together with a Nextel 440 thread.
Manufacturer: HiTemp Insulations, Oceaneering Thermal Systems
Technical Readiness Level: 9
Last Modified: 2001-10-01

Description:

• A development of the basic AFRSI TPS architecture, AFRSI-2500 is a quilted blanket TPS consisting of a woven alumina-borosilicate outer fabric, a woven glass inner fabric, and fibrous alumina batting sewn together with alumina-borosilicate thread. For most applications, a water-proofing agent would typically be applied to AFRSI-2500 at the factory and again between flights. Also, a surface coating of a ceramic material such as C-9 would most likely be required. In addition to meeting emittance requirements, the coating makes the outer surface more rigid and helps to protect the blanket's top surface fibers from aerodynamically-induced abrasion. <BR><BR> Compared to tile-type TPS, AFRSI-2500's installed cost is low, but its aerodynamic capabilities are far more limited. It has a much rougher surface finish than most tiles and therefore has an increased propensity to force a laminar boundary layer into turbulence. This increased roughness can also produce markedly amplified local heating where boundary layers are relatively thin, such as the windward side of most reentry vehicles. Additionally, AFRSI-2500 has lower tensile and shear strength compared to tiles, making it less applicable in areas of high aerodynamic loading; especially rapidly fluctuating aerodynamic loads. Although the blanket is very flexible during installation, its surface becomes hardened after application of the C-9 coating and brittle after thermal exposure. This material has a higher thermal conductivity when measured parallel to the blanket surface than when measured through the blanket. Only data for thermal conductivity normal to the plane of the blanket is given below. Data shown is for a .967" thick, 9.36 lb/ft3 blanket from an EMTL Final Report No. 1817. Conductivity data for AFRSI-2500 of other thicknesses may vary due to its non-uniform density construction. The same report documented some tests on a similar thickness of AFRSI where it had 3-5% lower thermal conductivity at higher pressures and 15-25% lower thermal conductivity at lower pressures than AFRSI-2500.

Point of Contact:

• Marc Rezin
• NASA Ames Research Center
• mrezin@mail.arc.nasa.gov