Testing Smile’s X-ray camera

In July 2025, engineers at ESA’s technical heart, ESTEC, tested the Smile spacecraft’s soft X-ray imager (SXI). SXI will be the first-ever camera to take X-ray photos of Earth’s magnetic field.

The engineers were checking for cracks in SXI’s fragile optics following mechanical and thermal testing of the spacecraft. Though the optics were undamaged, they found a cobweb or thread of glue that will be cleaned in the coming weeks.

This photo looks directly into the instrument, which follows a design inspired by lobsters’ eyes. It uses a lightweight, well-established and cost-effective technique called micro pore optics to focus X-rays.

The photos taken by SXI will help us map out how the magnetic field – our shield against the solar wind – moves and changes in shape in response to being hit by particles from the Sun.

Read more about the final stages of the Smile test campaign

Smile (the Solar wind Magnetosphere Ionosphere Link Explorer) is a collaboration between the European Space Agency (ESA) and the Chinese Academy of Sciences (CAS).

[Image description: Close-up of a spacecraft instrument in a cleanroom. The bottom section shows a large black rectangular opening with slats inside, framed by copper-coloured edges. Above it, there are numerous orange cables and electronic components. A person’s hand holding a torch is visible on the right, shining light on the equipment.]