project harp | in 1966 the project installed its third and final 16-inch gun at a new test site in yuma, arizona. on november 18, 1966 the yuma gun fired a 400 lb (180 kg) martlet 2 projectile at 7,000 ft/s (2,100 m/s) sending it briefly into space and setting an altitude record of 180 km (590,000 ft; 110 mi) [wikipedia]