A closeup of the stitching being done on pieces of insulation blankets inside the ring that fits in the nose cap of Discovery.

A closeup of the stitching being done on pieces of insulation blankets inside the ring that fits in the nose cap of Discovery. The blankets consist of layered, pure silica felt sandwiched between a layer of silica fabric (the hot side) and a layer of S-Glass fabric. The blankets are semi-rigid and can be made as large as 30 inches by 30 inches. The blanket is through-stitched with pure silica thread in a 1-inch grid pattern. After fabrication, the blanket is bonded directly to the vehicle structure and finally coated with a high purity silica coating that improves erosion resistance.