Design and Qualification of HERSCHEL Instrument Helium Cooling System

Herschel is the fourth cornerstone mission in the European Space Agency (ESA) science programme. It will perform imaging photometry and spectroscopy in the far infrared and submillimetre part of the spectrum, covering the 57-670 µm wavelength range. This successor of the Infrared Space Observatory (ISO) is scheduled to be launched by an Ariane 5 in 2007. Once operational Herschel will offer a minimum of three years of routine observations.

EADS-ASTRIUM, in charge of the Extended Payload Module, has involved AIR LIQUIDE in the design and manufacturing of major components of the spacecraft cryostat: the two Helium Tanks, all Thermal Links [1.6 K - 9 K], the Optical Bench Helium Cooling Loop, the three Thermal Shields and all the Helium System Tubing from the tanks to the Cryostat Vacuum Vessel. All these elements contribute to the final aim of the system to provide the required cold environment to the Herschel Focal Plane Units.

This paper presents the items provided by AIR LIQUIDE, from design to qualification. Particular emphasis is given to the leak test with superfluid Helium of the main tank equipped with its tubing.