An analytical investigation has been made of the flight mechanics, aerodynamic heating, and system weight for a booster recovery system in which a single large balloon is used as both a decelerator for reentry and a buoyant device for final recovery. The balloon was assumed to use ram air for maintenance of inflation and to use burners to heat the internal air to provide buoyancy in the atmosphere at low altitude for final recovery. The specific application of the system investigated was for the recovery of the Saturn S-1C booster. The study indicated that a balloon made of conventional glass-fiber cloth, treated by a relatively inexpensive process to provide added heat resistance, could withstand the conditions encountered during both the deceleration and the buoyant phases, and that the deceleration levels were within acceptable levels for the booster. A balloon diameter of 275 feet (84 meters), or possibly less, was adequate for the task, and the total recovery-system weight was of the order of 45,000 to 50,000 pounds (20,412 to 22,680 kilograms). The use of a recovery system of this weight would result in a reduction in mission payload weight of about 3.5 percent. Although the subject recovery system appears feasible from the standpoint of factors studied in this investigation, there are many possible problem areas, particularly in the area of flight mechanics, that would have to be investigated before it could be considered feasible.