The Comas sola mission to test the HUYGENS/HASI instrument on board a stratospheric balloon

Abstract The HUYGENS Atmospheric Structure Instrument (HASI) was designed to characterise the atmosphere of Titan during the descent of the HUYGENS probe in the framework of the NASA/ESA CASSINI/HUYGENS mission in November 2004. A balloon campaign was conducted in Leon, Spain, in December 1995, in order to test the HASI hardware and software in the terrestrial atmosphere and investigate the influence of the HUYGENS probe on the electrical measurements in a real environment. The subsystems from the HASI instrument: the Pressure Profile, the Accelerometer, the Temperature Profile and the Permittivity, Wave and Altimetry packages with their corresponding sensors were accommodated on a HUYGENS 1:1 mock-up and launched by a stratospheric balloon crossing a distance of 340 km and reaching a maximum altitude of around 30 km. The Huygens mission at Titan was simulated by a drop test; the probe was separated from the balloon in order to descent to ground dragged by a parachute. Measurements have been performed both in the ascending and descending phases.