LAUNCH PREPARATION OF THE HERSCHEL CRYOSTAT

The cryostat for the ‘Herschel Space Observatory’ for the European Space Agency (ESA) science program, successfully launched with Ariane 5 on 14^th of May 2009, was designed for 6 days ground hold time and 3.5 years lifetime in orbit. Due to a leak in the secondary tank, detected very late in the program, the cryostat’s configuration and the operations for launch autonomy had to be changed. The logistics for high purity liquid helium supply, the cryo‐vacuum set‐up for superfluid helium filling on the launcher and the operations for liquid helium cooling for the last days under the Ariane fairing will be described. The final cryostat conditions at launch are explained.