The Solar Wind Magnetosphere Ionosphere Link Explorer (Smile), a joint mission between the European Space Agency (ESA) and the Chinese Academy of Sciences (CAS), has completed its ten-month Assembly, Integration and Testing (AIT) phase, ESA said. The spacecraft is designed to give scientists an unprecedented view of how Earth’s magnetic environment responds to solar particles and radiation using X-ray and ultraviolet cameras, as well as particle and magnetic field detectors.
The AIT campaign began in November 2024 and concluded in September 2025 at ESA’s ESTEC technical centre in the Netherlands. With testing finalised, Smile will now move into launch preparation activities ahead of its planned liftoff on a Vega-C rocket between 8 April and 7 May 2026 from Europe’s Spaceport in French Guiana. ESA said the exact launch date within the window will be confirmed early next year, citing the need for “careful planning” due to a heavy launch schedule at the site.
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ESA Director of Science Carole Mundell said the collaboration with Chinese partners had progressed smoothly. “I’m very proud that the collaboration between our Chinese colleagues and our ESA teams has gone so well and that we’re on the right track to launch in spring 2026,” she said, adding that Smile builds on the 24-year legacy of ESA’s Cluster mission that ended operations last year. She described the new spacecraft as “the next big step in revealing how our planet’s magnetic shield protects us from the solar wind.”
Smile is expected to leave ESTEC in February for transport to French Guiana. The spacecraft will travel by boat from the Port of Amsterdam, a journey ESA said will take around 12 days. Once at the launch site, teams will begin the final preparation campaign ahead of integration with the Vega-C launcher.
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ESA has also released new images and video documenting the mission’s final test stages at ESTEC, including vibration assessments and qualification reviews completed between July and September 2025.
Source: ESA