Exotic design for an intercontinental missile using a gas core fission reactor for cruise propulsion. Studied circa 1957.

The Tu-123 was an exotic missile design using an airbreathing kerosene/nuclear mixed propulsion engine. It was proposed as an alternative upper stage on the 'DP' winged rocket system in place of the Tu-130 hypersonic glider. The engine would have given the missile a range in excess of 4000 km (perhaps essentially unlimited, as the American SLAM/Project Pluto) at a speed of 3000 km/hr. Other sources assign the Tu-123 designation to the conventional missile also known as Tu-133.

Manufacturer: Tupolev. Total Mass: 35,000 kg (77,000 lb). Core Diameter: 1.70 m (5.50 ft). Total Length: 24.80 m (81.30 ft). Span: 8.50 m (27.80 ft). Standard warhead mass: 3,000 kg (6,600 lb). Number Standard Warheads: 1. Standard warhead: 205. Boost Propulsion: Kerosene/Nuclear. Maximum speed: 3,000 kph (1,800 mph). Minimum range: 4,000 km (2,400 mi).