8 x 10 Color Photo Signed Air Force B-52 X-15 LAUNCH Test Pilot; JOE COTTON.
After receiving a full scale ablative coating to protect the craft from the high temperatures associated with high-Mach-number supersonic flight, the X-15A-2 (56-6671) rocket powered research aircraft was then covered with a white sealant coat and mounted with additional external fuel tanks. This ablative coating and sealant would help the #2 aircraft reach the record speed of 4,520 mph (Mach 6.7). Under the lower fin is a dummy ramjet engine. It was intended to use the X-15A-2 for tests of an actual engine but this never happened.