Purpose of the flight and payload description
The objective of the flight was to validate a new balloon envelope tearing system to be actuated after the payload separation. This mission also served to test new instrumentation aimed to characterize the mechanical behavior of the flight chain.
Starting in 2005, CNES Balloon flights in France were seriously constrained in terms of safety due to increasing population in flight zones. As a result, flight window opportunities were sharply reduced in order to comply a minimal damage probability (material and human damages). On this regard, the envelope deflation phase at the enf of a flight has an important impact on the envelope drag coefficient. Residual helium inside the envelope can maintain a residual lift reducing the expected descent rate and generating a dispersion in the descent trajectory from flight to flight that increase the size of the potential landing zone.
Developments were initiated in order to cope with these problems and improve the landing precision. CNES balloon engineers focused on developing a new deflation system and a new parachute system for zero pressure balloons (ZPB), in order to reduce the size of the impact uncertainty zone.
In order to understand the behaviour and measure the performance of the new deflating system, CNES developed a light video system to get pictures of the envelop in its descend phase from separation point to the landing zone. Simultaneously, the envelope trajectory during the descent to the ground is recorded in order to determine the ballistic coefficient.
Details of the balloon flight
Balloon launched on: 9/12/2009
Launch site: European Space Range, Kiruna, Sweden
Balloon launched by: Centre National d'Etudes Spatiales (CNES)
Balloon manufacturer/size/composition: Zero Pressure Balloon model 100z Zodiac - 100.000 m3
End of flight (L for landing time, W for last contact, otherwise termination time): 9/12/2009 at 8:30
Landing site: 120 km ESE from Kiruna, Sweden
Payload weight: 595 kg