Cutaway view of the Soyuz rocket fairing carrying a pair of Galileo satellites. – photo © ESA – J. Huart, 2014

Europe’s latest Galileo satellites are fully fuelled, leaving them ready to be attached to their launcher upper stage in preparation for their 11 September launch, it was reported by the European Space Agency (ESA) on 28 August.

Galileo 9 and 10 are due to launch atop a Soyuz launcher at 0408 GMT on 11 September from Europe’s Spaceport in French Guiana.

Technicians donned SCAPE (Self Contained Atmospheric Protective Ensemble) suits to fill each satellite with sufficient hydrazine fuel for their planned twelve years of operations in space. This fuel is needed for fine-tuning of their orbital paths following their launch, followed by routine orbital and attitude control in the course of their working lives.

Each Galileo satellite needs to keep its navigation antenna trained on Earth’s disc at all times, employing dedicated infrared Earth and Sun sensors for this purpose.

This marked the first time Galileo had been fuelled within the Guiana Space Centre’s 3SB preparation building. Previously the S5 fuelling building was dedicated to this purpose, but upgrades by Arianespace mean fuelling can now take place at the same location where they will subsequently be attached to their Fregat upper stage, streamlining the satellite preparation process.