against US missiles and their ICBMs against US bomber fields could inflict serious damage. The one weapon system that was not open to attack was the US Navy's Polaris missile system. The Polaris equipped submarines could cruise in large areas of the Atlantic or Pacific where the Soviet fleet was unable to find them, and launch their missiles with impunity. If the goal of the nuclear force was to maintain deterrence by ensuring that a counterstrike would be launched, Polaris met this goal in a way the existing Air Force fleet could not. This fact was more worrying to the Air Force than the Soviet arsenal and generated a number of internal reports on how to deal with this threat to their dominance in the strategic field. WS-199 and WS-138 In response, in 1957 the Air Force began studying solutions to the "Puzzle of Polaris" under the WS-199 program. WS-199 was a grab-bag effort, studying anything that might improve the survivability of the Air Force strike capability. Primary among the concepts were two air-launched ballistic missiles, Bold Orion and High Virgo. These systems would give the Air Force a method somewhat similar to the Navy's; in times of high alert, the bomber force would be sent to holding positions far outside the range of any Soviet defenses, and then launch their missiles on command. Using aerial refueling, a bomber might be expected to be able to loiter for as long as a day. This system had a major advantage compared to Polaris, as the aircraft could be sent radio instructions to retarget the missiles before launch. In theory, the bombers could be used as a second-strike weapon, attacking only those targets that had been missed in a first-strike, or alternately, being switched from counterforce to countervalue targets or vice versa. Ground-based systems like Atlas and Polaris lacked this ability, and could only be retargeted with a significant amount of effort. Even the latest Air Force design, the LGM-30 Minuteman, required changes in targeting data to be loaded from magnetic tape in a process that took several weeks. WS-199 was generally successful, but the two ALBMs had shorter range than desired. The Air Force tendered bids for a longer-range version in early 1959. Douglas Aircraft received the prime contract in May, and in turn subcontracted to Northrop for the guidance system, Aerojet for the propulsion system, and General Electric for the