A peek at the Herschel cryostat through the fairing

The Herschel cryostat seen through a door in the fairing of the Ariane 5. The cryostat will be flushed with helium via vents that pass through such doors until the day before launch when the cryostat will be closed, the vents and auxiliary connections removed, and the doors of the fairing shut. This process keeps the cryostat and the instrument detectors as cool as possible.