China and Europe jointly launched the Solar wind Magnetosphere Ionosphere Link Explorer satellite (SMILE) aboard a Vega-C rocket from Europe's Spaceport in French Guiana on Tuesday. Following liftoff, the satellite entered its planned orbit, with solar arrays deployed and all systems operating normally.

The mission, a collaboration between the Chinese Academy of Sciences and the European Space Agency, aims to study how the solar wind interacts with Earth's magnetic environment. The successful launch marks a milestone in China-Europe space cooperation.

"Earth is surrounded by an invisible magnetic field, the magnetosphere, which functions like a protective umbrella, constantly deflecting most solar wind — high-speed streams of charged particles from the sun. Without this protective shield, life on Earth would not be able to survive," said Wang Chi, a CAS academician and the Chinese principal investigator of the SMILE satellite.

Wang, who is also director of the CAS National Space Science Center, added that when charged particles penetrate the magnetosphere and enter near-Earth space, they can disturb the space environment, jeopardize the safety of orbiting satellites, interfere with communication and navigation systems, and even cause large-scale power outages.

However, previous studies of the magnetosphere's structure and related processes have largely relied on isolated observations and point measurements from individual satellites, making it difficult to establish a complete physical picture.

With the satellite now in orbit, scientists will, for the first time, conduct panoramic imaging of Earth's magnetosphere, achieving global imaging of its large-scale structure — a curved boundary sculpted by the solar wind that resembles a smile, echoing the mission's name. The mission will also quantitatively describe the physical processes governing solar wind-magnetosphere interactions, improving space weather forecasting capabilities.

To achieve these goals, SMILE carries four advanced instruments. The centerpiece is the space-borne Soft X-ray Imager, which detects X-rays emitted when charged particles from the solar wind interact with neutral particles in Earth's upper atmosphere, allowing scientists to visualize the previously invisible boundaries of the magnetosphere for the first time.