Manufacturing heritage panels for an EO Satellite

Primary structure lay-out & hexagonal C-modules

Flight model 6

Over the past 15 years, GTM has been contracted by Airbus DS NL for the build-to-print manufacture at GTM facilities of an unnamed EO program bus primary structures, a family of earth observation satellites. Apart from the development models, 5 Flight Models have so far been successfully delivered, the latest (FM4 and FM5) in the fall of 2017. A 6th Flight Model is currently in production, with delivery scheduled later in 2019.

Structural panel in semi-finishes state

Primary structure

The primary structure is a complex shape, consisting of several single flat panels, a baseplate and an integral manufactured hexagonal “barrel” or “C-module” with embedded heat pipes.

The single flat panels consist of honeycomb sandwich with 3 embedded U-shaped heat pipes with combined square and circular cross sections. On average, the panels have 50 inserts of various types each, structural reinforcement elements, and have various (thermal-) finishes on either side (including black paint and OSR’s).

Structural panels

Main characteristics

The main characteristics of the complex hexagonal structure are an assembly of six honeycomb sandwich panels with embedded heat pipes along the “circumference”. The embedded heat pipes are applied in five “horizontal” layers while they runs through maximum three panels, i.e. maximum two bends per heat pipe. Two groups of three straight heat pipes are applied in “vertical” direction. The hexagonal structure has 36 Aluminium brackets, up to 400 inserts and OSRs on six outer surfaces. Due to its composition, the hexagonal structure has very tight tolerances.