Alphasat's fit with its launcher is checked with an Arianespace flight adaptor

Xenon tanks fuelled

27 June 2013

Alphasat has passed its health checks with flying colours, and its xenon tanks are now also filled and ready to take to the air.

The team watched the Soyuz take off on Tuesday, and with this launch successfully completed the Kourou spaceport is now being prepared for its next task: the upcoming Alphasat launch.

Most of the satellite health tests were performed automatically. Some could even be run in parallel, and the teams were alerted whenever the system found inconsistencies. All of the onboard equipment has been given the go-ahead.

The next step was to fill the tanks with more than 200 kg of xenon, a colourless, odourless gas that is obtained from liquid air and made up of heavy molecules. It is used by the satellite’s electrical propulsion systems to regulate its north-south station-keeping and so maintain its position once it reaches orbit. During fuelling, the tanks’ temperature and pressure levels were monitored very closely.

In total, the process took around two days, with the gas being introduced more and more slowly until the tanks were filled.  

The fuelling operations will continue next week, this time with the thrusters. In contrast to the xenon tanks, the thrusters will take around two weeks to be completely filled with chemical propellant. The chemical fuel of bi-propellant and helium is what will drive the satellite to geostationary orbit after launch.

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