X-15A-2

The X-15 No. 2 had been damaged in a crash landing in November 1962. Subsequently, the fuselage was lengthened, and it was outfitted with two large drop tanks. To protect it against aerodynamic heating, researchers had coated it with an ablative coating covered by a layer of white paint. These changes allowed the X-15A-2 to reach a maximum speed of Mach 6.7, although it could be sustained for only a brief period.