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High altitude polyethylene balloons and standard rubber weather balloons differ greatly in size, construction, and utility. The difference between these two types of balloons historically has been the subject of misunderstandings in that the term “weather balloon” is often used to describe both types of balloons.

High altitude polyethylene balloons are used to transport scientific payloads of several pounds to several tons to altitudes of nearly 200,000 feet. Polyethylene balloons do not increase in size and burst with increases in volume as they rise, as do standard rubber weather balloons. They are launched with excess capacity to accommodate the increase in volume. This characteristic of polyethylene balloons makes them substantially more stable than rubber weather balloons and capable of sustained constant level flight, a requirement for most scientific applications.

Fig. 48. Relative sizes of a modern high altitude polyethylene research balloon, an airliner, and a hot-air balloon. Inaccurate characterizations of the giant high altitude research balloons as “weather balloons” (which are typically 15 feet in diameter) has historically been the source of confusion. (courtesy of Mike Smith, Raven Industries) Raven Industries 40 million cubic foot balloon. 450 ft in diameter at 130,000 feet DC-9 airliner 104 ft long Hot-air balloon. 50 ft in diameter