LONG DURATION BALLOON TEST

The CNES Balloon Division studied in early 90's a new type of open-neck stratospheric balloon with a long-duration flight capability. Its main feature would be to ensure a stable flight level under all conditions, during day and night, without the need to release ballast. The approach adopted was to cover the top of the balloon envelope with an insulating "cape" corresponding to 3% of the total envelope area under daytime conditions. As the balloon descended after sunset, its volume would decrease while the proportion of the gas bubble covered by the cape would increase to 50%. Even under the most adverse radiative conditions, this configuration would produce a sufficient improvement in the balloon's heat budget to ensure a stable float altitude in the lower stratosphere. At sunrise, the balloon would ascend to its daytime float altitude, making it possible to repeat a large number of day-night cycles.

In order to demonstrate the validity of the theoretical work, the CNES Balloon Division flight tested the first balloon of this type on April 26 1990, from its base in Aire-sur-l'Adour in southwest France. The prime aim of this flight was to demonstrate the technology, which was effectively achieved since the results obtained agreed with predicted performance.

Balloon launched on: 4/26/1990
Launch site: Centre de Lancement de Ballons CLBA, Aire Sur L'Adour, Landes, France  
Balloon launched by: Centre National d'Etudes Spatiales (CNES)
Balloon manufacturer/size/composition: Zero Pressure Balloon 400.000 m3
End of flight (L for landing time, W for last contact, otherwise termination time): ??/??/1990

• Concept for an open-neck stratospheric balloon with long-duration flight capability Advances in Space Research, Volume 13, Issue 2, p. 119