Design and development
WS-119L program to develop long-distance, high-altitude balloons for
aerial reconnaissance, the United States Air Force initiated WS-124A in early 1953 to develop a method of delivering weaponry to targets in the
Soviet Union using
 such a capability was considered potentially valuable in the event of a limited nuclear conflict, or in a "
broken-back" scenario following a massive nuclear exchange.
The WS-124A balloons were intended to fly at altitudes of roughly 38,600 feet (11,800 m), within the
jet stream; as
weather forecasts were considered to be sufficiently accurate to forecast approximately three days of wind patterns, the design flight duration was for 60 hours, in which they were expected to cover a distance of 1,500 nautical miles (1,700 mi; 2,800 km).
 The WS-124A balloon was designed to be capable of launching in wind speeds of up to 30 knots (35 mph; 56 km/h).
It was accepted that there would be an inherent inaccuracy in the concept; the expected target area was 360 nautical miles (410 mi; 670 km) by 480 nautical miles (550 mi; 890 km),
 which was considered acceptable as the designed payloads involved
biological weaponry, although
incendiary bombs, for starting forest fires, were also considered as a payload.
 It was believed that releasing chemical or biological agents from the balloons could contaminate an area "comparable in size to that affected by a low-yield
 Some sources claim that
dirty bombs were also considered for carriage by WS-124A.
 In addition, the ability of the balloons to spread
propaganda leaflets across enemy territory was considered useful.