Can anyone ID this jet with booster underneath?

The Regulus II, designated "SSM-N-9" and later "RGM-15", was a sleek, pretty dart of a missile, with swept wings and no tailplane like the Regulus I, but with the air intake under the belly ahead of the wings and small canard fins on the nose. The wings and tailfin folded for storage. Preliminary design work began in 1951, with Vought submitting a proposal to the Navy in late 1952, and the Navy awarding the company a development contract in April 1954, specifying construction of prototypes.

The initial prototypes were fitted with retractable tricycle landing gear and a drag parachute, allowing them to take off and land from an airstrip, and were powered in cruise flight by a Curtiss-Wright J65 turbojet, an American copy of the British Sapphire engine. The Sapphire was strictly an interim fit, however, since it could not support sustained supersonic flight, and production missiles were fitted with a General Electric J79 afterburning turbojet engine with 66.7 kN (6,800 kgp / 15,000 lbf) thrust.

Production missiles were launched off a rail by a solid-fuel booster rocket with 512 kN (52,160 kgp / 115,000 lbf) thrust. The Regulus II flew in continuous afterburner, operating at high altitude in supersonic cruise at Mach 2 plus. It had a large fuel supply to provide the required range and featured an automatic fuel trim system. The Regulus II was guided by an INS. The warhead separated during terminal dive to target. This made interception more difficult, and also eliminated the need to stress the airframe to tolerate a dive into the target.

Initial flight of a prototype was on 29 May 1956, at Edwards Air Force Base in California. The first rocket-boosted launch was on 13 November 1957, also from Edwards.