Payload Module structural support

The Payload Module (PLM) provides the main supporting structure for both the payload instruments and the payload support systems. Instrument sensors and antennae are mounted on the external panels, while most of the electronic units are accommodated inside the PLM.The accommodation of the large suite of instruments is a significant design driver for the overall PLM configuration. The PLM also houses all of the avionics necessary for power regulation and distribution, command and control, and the handling of scientific data.The Payload Module (PLM) is the main supporting structure for the complement of instruments and various deployable features. The internal design of the PLM allows these instruments to work optimally.

PLM structural designThe MetOp PLM structural design concept is based on the Environmental Satellite (Envisat) and consists of a 'box' shape structure with a central cylinder as the main structural load path to the Service Module (SVM). The PLM structures can be categorised as being primary or secondary structural elements.

Thermal control of the PLM is passive (i.e. radiators and MLI) and supplemented by heaters.

On the MetOp spacecraft command and control is implemented separately to measurement data handling. This does not work for the American instruments inherited from the National Oceanic and Atmospheric Administration (NOAA). A dedicated NOAA Interface Unit (NIU) has therefore been implemented to adapt the NOAA interfaces to European standards.