...Cryogenic age has not spread over the Kourou river, or a new glaciation era has not suddenly hit French Guyana as it may be suggested by the picture below...
This is just the quiet
Kocher river in
Sindringen last January. A romantic place in the
Baden-Württemberg near
Lampoldshausen where the propellant drums for MSG were produced by
ASTRIUM and were accepted by ESA and Thales before shipment by road and boat to Degrad de Cannes, the Cayenne harbour.
Two drums are needed to fuel MSG: one for
MON, one for
MMH plus two back up drums (i.e. four drums in total).
Here under is a representation of one of these highly securised containers.
The scale enables to reach the top of the drum for the leak detection measurements on the flanges, valves and manometers... these measurements are repeated at various steps of the transport to make sure that the drums are tight.
The fuelling (MON and MMH) will be done in EPCU S5B facility which has been already described in a
previous message.
But...another operation will take place before the fuelling: The pressurisation of the
Helium tank to 260 Bars (this operation will still be done in EPCU 5C). This
inert gas will play the essential role in orbit to pressurise the MON and MMH tanks to about 13 bars in order that the different satellites manoeuvres required for the mission can be achieved. 85% of the propellant will be consumed within the first 2 weeks of the mission for the proper firing of the two Liquid Apogee Motors (LAM). With four Apogee Motor Firings (AMF), MSG-3 will move from the (elliptical)
transfer orbit to its
Geostationary position. The remaining 15% of propellant gas will be used for the usual orbit and attitude control manoeuvres performed by the thrusters during the 7 year nominal life time... and very likely more.
The Helium tank filling will be made using the Fill and Drain Valve (FDV), the last blue cap on the left, located just under the battery as showed on the picture below. The four other FDVs are used for testing only. Note that the Multi Layer Insulation (MLI) is not completely installed for permitting this filling operation.
As the filling is an hazardous operation (static and dynamic risks linked to pressurisation), two large protective"walls" called blasting shields have been installed in the S5C clean room.
When the Helium pressurisation will be completed by mid of next week, the walls will be removed and MSG-3 will be transported to S5B for the fuelling.
By the way, all walls have eventually to be removed one day... or painted to tell their story!
Berlin,
Postdamer Platz, June 6th 2010.
Note: The technical part of this message was proof read by Rolf our propellant expert
