How to test an extendible spacecraft boom designed to work in weightlessness down here on the ground? This is when helium balloons come in handy.

The 3 m-long magnetometer boom of a ‘structural and thermal model’ prototype of the Solar wind Magnetosphere Ionosphere Link Explorer (Smile) was deployed with balloons attached during its test campaign at the ESTEC Test Centre in the Netherlands, the largest satellite test establishment in Europe.

Smile is a joint mission between ESA and the Chinese Academy of Sciences (CAS) and will aim to build a more complete understanding of the Sun-Earth connection by measuring the solar wind and its dynamic interaction with the magnetosphere.

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