The HUYGENS Thermal Shield: Design, Development and Qualification Rationale

The ESA HUYGENS probe is scheduled for launch as part of the CASSINI mission to the Saturnian system in 1997, due to arrive at TITAN in late 2004. The HUYGENS probe shall then perform a 2.5 h exploratory descent in TITAN's atmosphere. This descent phase will be preceded by a 3 mn Entry phase during which the velocity of the European probe will be reduced from 6 km/s down to around 400 m/s. This will be obtained by means of a 2.7 m diameter shield.

This paper presents the general rationale used for the shield design, development and qualification.The following steps are described:

• choice of shield concept and materials
• verification of compliance of thermal protection materials with shield requirements
• development of new processes imposed by the mission specificities
• verification of interface compatibility between thermal protection materials and shield structure
• qualification of the thermal protection system and of the shield design to the entry mechanical loads and thermal fluxes.

The preceding tasks are now successfully achieved. The flight model shield will be provided by AEROSPATIALE to ESA on September 15th, 95.