Herschel has been mounted on the top of the Ariane 5 rocket, where it now sits on top of it’s lower passenger, the Planck Surveyor observatory.
With Herschel and Planck now on Ariane 5, preparations for the May 14 launch from French Guiana move into their final phase – with several peculiarities for the pioneering dual space science mission.
This includes a “top-up” of Herschel’s cryostat cooling system with liquid helium, which is now underway and will continue into next weekend. The cryostat will keep the temperature of Herschel’s scientific instrument detectors close to absolute zero (–273ºC), enabling the space telescope to provide an unprecedented view of the “cold universe” during observations made in far-infrared and sub-millimeter wavelengths.
Once the liquid helium top-up is completed, the Herschel/Planck stack will be covered by Ariane 5’s nose-cone, the final step before launch.