Three Clusters visible as FM7 mating begins
15 February 1999The fleet of Cluster II spacecraft is growing daily inside the giant cleanroom at theDornier Satellitensysteme plant in Friedrichshafen, Germany. Three of thefour spacecraftare now visible in various stages of construction
Flight model (FM) 6, the furthest advanced of the trio, is now fully assembled and is undergoing the final stages of electrical testing. It should be shipped to IABG in Munich early next month for extensive environmental tests.
Nearby is FM 7, which recently began its lengthy process of assembly and integration. The latest landmark for FM7 arrived today (16 February) when the main equipment platform was mated to its central cylinder.
This equipment platform consists of an aluminium-skinned honeycomb panel which is reinforced by an outer aluminium ring. Most of the subsystems, such as the power and computer processing hardware, have already been integrated on its lower surface. In the coming weeks, the science experiments will be placed on top of the main equipment platform. Eventually, six curved solar array panels will also be attached around the outside of the platform.
The FM7 spacecraft's central cylinder is made of an aluminium honeycomb structure covered with a skin of carbon-fibre reinforced plastic. The satellite's main engine, two high-pressure fuel tanks and other parts of the propulsion system were installed inside the cylinder prior to its mating with the equipment platform.
Also in the clean room is the skeleton of FM 5 (Phoenix), which is partially constructed from spacecraft spares left over from Cluster I. FM5 will be the last of the Cluster II quartet to be assembled and tested.
Each cylindrical Cluster II spacecraft measures 2.9 metres in diameter and 1.3 metres in height, and will carry an identical set of 11 scientific instruments. All four must be completed by next March if they are to meet their launch deadlines in June and July 2000.