Cutting-edge x-ray telescope completed for solar wind research mission

The final instrument has been handed over for integration into a spacecraft that promises to deliver new insights into these cosmic phenomena.

The Soft X-ray Imager (SXI) on the Solar wind Magnetosphere Ionosphere Link Explorer (SMILE), led by the University of Leicester, is a state-of-the-art wide-field X-ray telescope. Utilising micropore optics, it will spectrally map the location, shape, and motion of Earth's magnetospheric boundaries.

Developed through a collaborative effort involving the University of Leicester, Mullard Space Science Laboratory (MSSL), and the Open University within the UK, alongside several European institutions, the project saw UK space engineers contribute key subsystems. These include the main telescope assembly, X-ray optics module, advanced X-ray detector system, and the associated readout electronics.

The SXI is the first instrument delivered using the facilities at Space Park Leicester. The Assembly, Integration, and Test (AIT) Team there successfully integrated the space-flight subsystems within a specially designed cleanroom to complete the SXI Telescope.

Following a rigorous development programme, which involved building and testing several models of the instrument to endure the harsh conditions of space, the final flight model has been delivered to Airbus Defence and Space in Madrid. This model will be integrated onto the European Space Agency (ESA) platform, which serves as the main instrument hub on the SMILE spacecraft.

Credit: University of Leicester

SMILE is a joint collaborative science mission between ESA and the Chinese Academy of Sciences (CAS) aimed at studying the solar wind’s interaction with Earth’s magnetic environment. It is scheduled for launch in September 2025 on an ESA Vega-C rocket from Kourou, French Guiana.

Over the next few months, SXI and other instruments that make up the SMILE payload will undergo system tests in conjunction with the platform before the complete spacecraft is integrated at the European Space Technology Centre (ESTEC) in the Netherlands.

Dr Steven Sembay, SMILE SXI Principal Investigator at the University of Leicester, commented: “SXI is a powerful but compact X-ray telescope that has been challenging to design within the constraints on size and mass and the space environment imposed by the SMILE mission. It has been a real team effort to meet and get past all these challenges and is a testament to both the technical skill of our University-based engineers here in the UK and the great collaborative atmosphere all across our international consortium.”

Dr Jennifer Carter from the University of Leicester School of Physics and Astronomy explained the mission’s significance: “Our Earth is protected from the solar wind by its magnetic field, which acts like a shield. SMILE will transform our understanding of this highly dynamic magnetosphere. SXI will image this magnetic shield, whilst a different camera will take ultraviolet pictures of aurora in the Northern Hemisphere. For the first time ever, we will see how changes to this shield cause effects in the upper atmosphere at the same time.”

Dr Colin Forsyth from Mullard Space Science Laboratory, the SMILE Co-Principal Investigator at the Mission level, added: “SXI is crucial to the innovative observations that SMILE will provide, enabling us to reveal the invisible structures and processes around Earth, so it is very exciting to see this key instrument ready to go.”

Dr Caroline Harper, Head of Space Science at the UK Space Agency, stated: “This a major milestone for Space Park Leicester and a huge achievement for the University of Leicester who led this international team to develop the cutting-edge instrumentation for SMILE, that will help us to understand more about the solar wind and how space weather can impact Earth.

“Space weather was responsible for the beautiful auroras that got the whole of the UK staying up, and looking up, in May 2024. It also brings potential risks such as radio blackouts, disruptions to satellites, and power grid failures. So, it is vital we build our understanding and gain new insights into the solar winds that bombard our planet’s magnetosphere.

“The UK Space Agency has supported the delivery of this instrument with approximately £13m of funding, building on our mission to invest in cutting-edge technologies and world-class science that bring the benefits of space back to citizens on Earth. We look forward to the next steps in the project.”

The completion and delivery of the SXI telescope represent a crucial step towards enhancing our understanding of the solar wind and its impacts, paving the way for significant advancements in space weather research.