The Solar wind Magnetosphere Ionosphere Link Explorer (SMILE) mission, a collaborative effort between the European Space Agency (ESA) and China, successfully launched into orbit. The Vega C rocket lifted off at 11:52 p.m. Eastern on May 18 (0352 UTC, May 19) from Kourou, French Guiana. The spacecraft separated from its launch vehicle approximately 57 minutes after liftoff, followed by the successful deployment of its solar arrays.
The SMILE mission is designed for a planned three-year duration to investigate the interaction between Earth’s magnetosphere and solar storms. This research aims to enhance the ability to predict the impacts of space weather. The 2,200-kilogram spacecraft, which includes 1,500 kg of propellant, was initially launched into a 706-kilometer orbit inclined at 70 degrees. Over the next month, SMILE will utilize about 90 percent of its propellant to achieve its highly elliptical science orbit.
Mission Objectives and Instrumentation
SMILE will reach an apogee of approximately 121,000 kilometers above the North Pole, offering a unique global perspective of Earth’s magnetosphere.
This view will be captured 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 highly elliptical orbit will also enable SMILE to conduct 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 the mission aims to provide the first images of the magnetopause, a structure whose shape has previously been unknown. He noted that prior space science missions could only offer localized measurements of these dynamics. Wang added that successful imaging would allow scientists to study the movement of this magnetic pulse and the transport of mass and energy from the solar wind, which is crucial for space weather prediction.
International Collaboration and Technical Details
The SXI, developed by the UK’s Leicester University, incorporates lobster-eye optics and some of the largest CCDs ever used in space, cooled to minus 120 degrees Celsius.
The SMILE mission was jointly developed by ESA and the Chinese Academy of Sciences (CAS). It 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 magnetometer instruments.
The SXI, developed by the UK’s Leicester University, incorporates lobster-eye optics and some of the largest CCDs ever used in space, 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 emphasized the mission's importance for understanding cause and effect, particularly given modern society's reliance on space infrastructure.
The mission experienced several delays, including component changes following an export control assessment in 2020 and disruptions caused by the COVID-19 pandemic. Despite these challenges, both ESA and CAS officials highlighted the success of their partnership. Mundell noted that the collaboration fostered learning across different engineering and scientific approaches. This launch marked the seventh flight for the Vega C rocket and the first instance where the Italian company Avio assumed the role of launch operator.
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