During the formative years of the space shuttle program, NASA Dryden F-15 and F-104 jets were used to flight-test various advanced Thermal Protection System (TPS) materials for the shuttles.
These tests included TPS materials from different locations on shuttle orbiters, and they were tested for everything from rain impact integrity, to air-loads strength and surface bonding.
During one such effort, NASA Dryden engineers conducted flight-testing of the orbiter’s advanced, flexible Felt Reusable Surface Insulation (FRSI) and Advanced Flexible Reusable Surface Insulation (AFRSI) TPS materials. These were the soft, sewn blanket-like materials that covered most of the upper surfaces of the orbiters, while black silicon tiles covered the underside, and reinforced carbon-carbon materials protected the nose and leading edges of the wings.
The objectives of the FRSI and AFRSI tests were to evaluate the performance of the materials at simulated shuttle launch aerodynamic loads, and also to provide a database for future advanced TPS flight tests.
These flights were flown mostly on Dryden’s F-104 test bed aircraft in the 1980s, with the TPS materials attached to a fin-like structure called the Flight Test Fixture (FTF) underneath the F-104.