HELSINKI — Scientists at the European Space Agency’s ESTEC and visiting Chinese counterparts conducted a series of spacecraft-rocket integration tests for a joint mission.

The Solar wind-Magnetosphere-Ionosphere Link Explorer (SMILE) mission is a joint mission of ESA and the Chinese Academy of Sciences (CAS). Teams conducted docking, satellite separation and impact tests with a prototype of the SMILE satellite developed by the Innovation Academy for Microsatellites of the CAS (IAMCAS) and the payload adapter for the mission’s Vega-C rocket at the European Space Research and Technology Centre (ESTEC), CAS stated Feb. 13. It is the first time a Chinese team has conducted such tests at ESA facilities.

Last year Airbus sent a structural thermal model of the payload module to Shanghai for integration with the IAMCAS platform and qualification of the satellite.

SMILE is a Sino-European joint mission expected to be launched in April 2025, according to CAS’s National Space Science Center (NSSC). SMILE was last year slated for launch in November 2024, following a number of delays to the project. 

The three-year mission will study the interaction between the solar wind and the Earth’s magnetosphere and knock-on effects in the ionosphere, as well as phenomena such as coronal mass ejections. It will operate in a highly inclined, highly elliptical orbit around Earth which will take it a third of the way to the Moon at apogee.

The mission was selected in 2015 from 13 joint Sino-European proposals. SMILE originally targeted launch on a Vega-C rocket from Europe’s Spaceport in Kourou in 2021, but has faced a number of delays.

“SMILE was very early on in 2016 intended for launch in 2021. Following initial studies and programmatic arrangements for the mission, the launch date was revised to be towards end-2023 to mid-2024 on the basis of which it was adopted by the ESA Science Programme Committee (SPC) in 2019,” David Agnolon, SMILE project manager, told SpaceNews via email.

“Following a number of technical difficulties and programmatic evolutions, among which a significant impact due to Covid, the development faced a one-year delay. The mission is on-track for launch in 2025, which will be confirmed at the Critical Design Review foreseen to take place mid-2023.”

CAS provides the propulsion and service modules, satellite bus and takes charge of mission operations for the mission, while also providing Chinese-developed instruments. ESA will provide the payload module, launcher, AIT facilities. SMILE will carrying the SXI (Soft X-ray Imager) featuring Lobster-Eye optics and the SWCX (Solar Wind Charge eXchange) X-ray imager. The spacecraft have a wet mass of around 2,200 kg.

The collaborative project builds on earlier cooperation on the Double Star mission in the early 2000s and ESA participation in CAS’s first round of missions under the Strategic Priority Program on Space Science in the mid 2010s.

Exchanges between China and ESA with a view to sending European astronauts to China’s Tiangong space station later this decade have, however, stalled, ESA Director General Josef Aschbacher said last month.

SMILE may not be the only project to be realized from the joint ESA-CAS workshops which led to the selection of SMILE.

Chinese teams have gone on to conduct studies on some of the proposals including the Discovering the Sky at the Longest Wavelength (DSL) mission. DSL proposes to send an array of 10 small satellites into lunar orbit, using the moon as a shield from Earth interference to study faint signals from the early universe. It is now one of 13 candidates for acceptance under CAS’s “New Horizons” program.

Andrew Jones covers China's space industry for SpaceNews. Andrew has previously lived in China and reported from major space conferences there. Based in Helsinki, Finland, he has written for National Geographic, New Scientist, Smithsonian Magazine, Sky...