It’s known colloquially as a ‘flying Dutchman’ operation: lowering an engineer down into ESA’s Large Space Simulator to make adjustments on the test item within; in this case the payload module of the newest in the MetOp series of weather satellites. The LSS is the largest vacuum chamber in Europe, based at ESA’s Test Centre in Noordwijk, the Netherlands.

MetOp is a set of three polar-orbiting satellites whose temperature and humidity observations from a relatively close 800 km-altitude orbit have sharpened the accuracy of weather forecasting. Procured by ESA for Eumetsat, the European Organisation for the Exploitation of Meteorological Satellites, MetOp-A was launched in 2006 and MetOp-B in 2012, with MetOp-C due to follow next year.

The 2.1 tonne module carries a suite of meteorology and climatology instruments, variously procured by ESA or sourced from Eumetsat, France’s CNES space agency and the US National Oceanic and Atmospheric Administration. Once testing is complete, MetOp-C’s payload module will travel to the Airbus Defence and Space facility in Toulouse, France, to be integrated with its service module – the segment of the satellite providing attitude and orbit control, electrical power and communications, and hosting the main computer. The launch of MetOp-C by Soyuz from Europe’s Spaceport in French Guiana is scheduled for October 2018.