Superpressure balloon
From Wikipedia, the free encyclopedia
A superpressure balloon is style of balloon where the pressure of lifting gas changes as the balloon temperature changes due to the heating and cooling of the diurnal cycle. This is an alternative to the more common approach of allowing the gas volume to change in response to diurnal heating and cooling. However, a change in gas volume will necessarily produce a change in the buoyancy of the aircraft which will necessarily lead to a change in altitude.
Superpressure balloons have the advantage of maintaining a steady altitude regardless of heating and cooling. A disadvantage is that they require much stronger materials than non-pressurized balloons. Superpressure balloons are typically used for extremely long duration flights of unmanned scientific experiments in the upper atmosphere.
The difference between a superpressure balloon and other types of balloon is that the buoyancy stays constant due to the volume staying constant. The envelope of a superpressure balloon is made of inelastic material with high tensile strength which does not deform when it is subjected to changes in pressure.
