A balloon trajectory prediction system

Safety requirements and the increase in balloon flight duration make a computerized balloon control system essential. Starting with a global thermodynamic model of a stratospheric balloon (NASA-SINBAD) and 48-h wind forecast data, a flexible system can be built to predict its trajectory. In order to increase the trajectory forecast accuracy, the thermodynamic model of SINBAD, related to infrared radiation and albedo, has been improved. The model and the methodology have been evaluated by comparing the altitude excursion of some already flown zero-pressure balloons, with the altitude excursion computed by SINBAD; meteorological and satellite data (METEOSAT) and meteorological forecast data have been used as input. This system, connected during the mission to the balloon's managing unit, will continuously update the forecast trajectory and will enable real and simulated data to be compared. In this way it will also be possible to simulate the balloon flight trajectory in case of any failures. This paper explains the solution adopted for this system and the application that was carried out for the Italian Space Agency's 2002 summer balloon campaign.