 Shortly in advance of the USAF visiting Avro in 1955 to review the Arrow's development, a contract was granted to North American Aviation for design studies for the LRIX, designated the North American XF-108 Rapier.Performance requirements were for a range of 1,000 miles, Mach 3, and combat altitude of 60,000 feet.In September 1957, Avro's Project Studies PS-1 and PS-2 were released.