U.S. Air Force cruise missile Navaho on the launch pad. Even though it never reached operational status before cancellation in 1957, Navaho research development contributed to the aeronautical research program. The heavy Navaho vehicle weighed 136,000 kilograms, capable of Mach-3 speeds, and used an improved V-2 engine, was boosted into the air by three liquid-propellant rocket engines of 135,000 pounds of thrust each. Variants of these engines were developed for Army's Redstone and Jupiter rockets.