The Solar wind Magnetosphere Ionosphere Link Explorer (SMILE), a joint satellite mission of the Chinese Academy of Sciences (CAS) and the European Space Agency (ESA), has passed its in-orbit test review and entered the scientific operation phase, the National Space Science Center under CAS announced. The move ends commissioning and starts the mission’s planned science campaign, aimed at the first panoramic imaging of how the solar wind interacts with Earth’s magnetosphere—the process that drives space weather and can disrupt satellites, power grids, and communications.
On Wednesday, China and Europe released the first batch of images and data from the mission’s four instruments. The Ultraviolet Imager returned the first uninterrupted panoramic images of northern-hemisphere auroras, including fine structure in the auroral oval. The Soft X-ray Imager captured a supernova remnant in the Large Magellanic Cloud, its first image and a calibration target for what is described as the first Earth-orbiting soft X-ray imager intended for magnetospheric work. The Magnetometer and the Low-Energy Ion Analyzer (also called the Light Ion Analyser) delivered the first high-resolution in-orbit measurements from very high Earth orbits, covering magnetic field and ion plasma conditions in regions that previous missions sampled only sparsely.
SMILE launched on May 19, 2026, from Europe’s Spaceport in Kourou, French Guiana, aboard a Vega-C rocket. After about a month of orbital maneuvers it reached its science orbit on June 20, with a perigee of 5,120 km and an apogee of 120,900 km. That highly elliptical path takes the spacecraft far above the northern hemisphere, nearly a third of the way to the Moon at apogee, so it can look back at the Sun-facing boundary of Earth’s magnetic field for long stretches of each orbit. In-orbit tests showed all mission units working normally. Payload checkout and calibration produced valid scientific data in line with expectations, and the CAS team completed all payload-module operations independently.
The spacecraft was jointly developed by CAS and ESA. It is the concluding mission of the CAS Strategic Priority Research Program in Space Science (Phase II) and follows the Double Star mission of 2003, the earlier China–Europe magnetospheric collaboration. Both sides described SMILE as a new milestone in mission-level cooperation: an equal, complementary partnership rather than a one-sided contribution of instruments. ESA is responsible for the payload module, the launch, one instrument, and part of science operations; CAS is responsible for the platform, three instruments, and mission and science operations. The planned science phase is about three years, with data to be shared with the wider research community.
The early results do not yet constitute the mission’s main magnetopause movie. Soft X-ray imaging of the dayside boundary is expected to improve as stray light falls toward a minimum around mid-October, when the imager should be better placed to record the magnetopause and the northern polar cusp. Even so, the commissioning images and in-situ data confirm that the four-instrument suite—global imaging plus local plasma and field measurements—is functioning. Mission managers say that combination should give space physics a new observational perspective and improve forecasts and mitigation of space-weather hazards.
Context. Earth’s magnetosphere is the cavity carved in the solar wind by the planet’s magnetic field. The solar wind, a supersonic flow of protons, alpha particles, and embedded magnetic field from the Sun, piles up at a bow shock, slows in the magnetosheath, and presses on the magnetopause. When the interplanetary magnetic field turns southward, reconnection opens the boundary, funnels plasma into the polar cusps, and powers auroras and geomagnetic storms. Those storms induce currents in power grids, increase drag and radiation dose on satellites, and disturb radio links. Until SMILE, that system was known mainly from in-situ fleets such as Cluster and Double Star, which sample single points, and from auroral imagers that see the ionospheric footprint but not the dayside boundary itself.
SMILE’s distinctive method is soft X-ray imaging of solar-wind charge exchange. Heavy ions in the solar wind steal electrons from neutral hydrogen in the geocorona and emit soft X-rays; the emission traces where dense solar wind piles up, outlining the magnetopause, bow shock, and cusps. A wide-field “lobster-eye” Soft X-ray Imager maps that glow while an Ultraviolet Imager records the northern aurora for up to about 40–45 hours at a time. The magnetometer, on a boom, and the light-ion analyser supply the local solar-wind and magnetosheath context needed to interpret the images. Proposed after a 2015 joint call, selected that year, and adopted by ESA in 2019, the mission is built to link cause in the solar wind to effect in the magnetosphere and ionosphere in one continuous view.
Featured image: A coronal mass ejection erupts from the Sun; its connection with Earth’s magnetosphere produced auroras. Credit: NASA/GSFC/SDO