The Solar wind Magnetosphere Ionosphere Link Explorer (SMILE) mission, a joint project between the European Space Agency (ESA) and China, successfully launched into orbit on May 18. The Vega C rocket lifted off at 11:52 p.m. Eastern (0352 UTC, May 19) from Kourou, French Guiana. The spacecraft separated from its launch vehicle approximately 57 minutes after liftoff, with solar arrays deploying successfully shortly thereafter.
SMILE is designed for a three-year mission to study the interaction between Earth’s magnetosphere and solar storms, aiming to improve space weather prediction capabilities. The 2,200-kilogram spacecraft, which includes 1,500 kg of propellant, was initially placed into a 706-kilometer orbit inclined at 70 degrees. Over the next month, SMILE will use about 90 percent of its propellant to reach its highly elliptical science orbit.
Mission Objectives and Instrumentation
The mission's highly elliptical orbit will allow SMILE to achieve an apogee of approximately 121,000 kilometers above the North Pole.
This position will provide a unique, global perspective of Earth’s magnetosphere using its wide-angle X-ray SXI and UVI ultraviolet cameras. Data will be downlinked to DLR’s O’Higgins Antarctic ground station during passes over the South Pole, at a perigee of about 5,000 km. The orbit also enables 45 hours of continuous aurora observations during each 51-hour orbital period.
Wang Chi, director general of the National Space Science Center (NSSC), stated that SMILE will capture the first images of the magnetopause, a magnetic field acting as a shell for Earth. He noted that previous missions only provided local measurements of these dynamics. Wang emphasized that imaging the magnetopause's movement as solar activity varies will be crucial for understanding how mass and energy are transported from the solar wind, which is vital for predicting space weather.
International Collaboration and Technical Details
ESA science director Carole Mundell highlighted the mission's importance, stating, "For the first time ever, we will be able to understand cause and effect." She added that this understanding is critical scientifically and for modern life, which relies heavily on space infrastructure.
SMILE was jointly developed by the European Space Agency and the Chinese Academy of Sciences (CAS). The mission was selected in 2015 from 13 proposals submitted by joint ESA-CAS teams. The spacecraft carries four scientific instruments: the soft X-ray imager (SXI), the ultraviolet imager (UVI), an in-situ ion analyzer, and a magnetometer. The SXI, developed by the UK's Leicester University, incorporates lobster-eye optics and large CCDs cooled to minus 120 degrees Celsius. This instrument focuses on solar wind charge exchange emission, which occurs when highly charged solar wind ions interact with neutral atoms. The combination of imagers and in-situ payloads will provide both global response views and simultaneous measurements of the particles driving these phenomena.
ESA science director Carole Mundell highlighted the mission's importance, stating, "For the first time ever, we will be able to understand cause and effect." She added that this understanding is critical scientifically and for modern life, which relies heavily on space infrastructure.
The mission experienced delays due to component changes following an export control assessment in 2020 and disruptions from the COVID-19 pandemic. Both agencies acknowledged the success of their partnership, with Mundell noting that the collaboration fostered learning across different engineering and scientific approaches. This launch marked the seventh flight for the Vega C rocket, with Italian company Avio serving as the launch operator for the first time.
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