Complex sentence: Propulsion was by a dual-thrust boost-sustain solid-propellant rocket supplied by the Grand Central Rocket Company and the Hercules Powder Company; a gyroscopic-driven autopilot stabilized the rocket in flight.
Split into simpler sentences: Propulsion was by a dual-thrust boost-sustain solid-propellant rocket supplied by the Grand Central Rocket Company and the Hercules Powder Company. A gyroscopic-driven autopilot stabilized the rocket in flight.