(C22) Fuelling Preparation

After the unloading from the Paylaod adaptor (CCU), MSG-4 has been weighed last Monday (08/06). The dry mass of the spacecraft is 1074 kg. This weighing method (double pesée) has been explained in a dedicated post for MSG-3 (MSG-3 on the weighing scale).
MSG-4 is set now on the fuelling stand where the filling of the propellant tanks with MON (oxidiser) and MMH (hydrazine fuel) will take place. About 970 kg of propellant (604 kg of MON and 366 kg of MMH) will be loaded for the nominal seven year mission.

 

ThalesAleniaSpace team removing hoisting devices after mating on the Fuelling stand

During the recent transfer activities, it was possible to get a view on a part that can rarely been observed as it is located beneath the spacecraft : the cooler cover. This cover, that will be ejected ca 8 days after the launch, protects an important area of the SEVIRI thermal subsystem: a series very fragile mirrors glued on the conical sunshield that helps to cool down the spacecraft during its mission.

 

View of the Cover Cooler seen through the payload adaptor

Coming back to the propulsion, today (09/06), the MON containers have been delivered in the dedicated storage room of the S5B facility as it can be seen from the TV monitors installed in S1B. The MMH containers are planned to arrive on Friday and will be stored in a separate room. These two components are dangerous substances for humans and environment and stringent safety precautions are implemented to prevent any accident. Only a dedicated ThalesAleniaSpace team (called in French "les ergoliers") is authorised to perform this fuelling operation.

MON container in S5B storage room

In parallel, the preparation and validation of the Fuelling Ground Segment Equipment (to be used to transfer the propellant from these containers to the tanks) are made.