Herschel cryostat cool-down setup

In this picture the Herschel spacecraft is set up for the cool-down of its cryostat vacuum vessel. After a bake out that removed unwanted volatiles from the system, the cryostat vacuum vessel was prepared for the filling of the cooling system with helium. The temperature in the cryostat was gradually lowered over a few weeks, with the outer vessel staying at ambient temperature.