The Solar wind Magnetosphere Ionosphere Link Explorer, Smile, has been given the green light for implementation by ESA’s Science Programme Committee.

The announcement clears the way for full development of this new mission to explore the Sun-Earth connection, which will be conducted in collaboration with China.

Smile is expected to revolutionise scientists’ understanding of the physical processes taking place during the continuous interaction between particles in the solar wind and Earth’s magnetic shield – the magnetosphere.

The mission will be a major scientific endeavour in collaboration between ESA and China, following on from the success of the Double Star / Tan Ce mission which flew between 2003 and 2008. Unlike Double Star, which started out as a China-only project, Smile is envisaged from the start as a joint ESA-China mission.

The scientific collaboration began with two workshops – one held in China, one in Europe – that were held to facilitate collaboration between Chinese- and European-based researchers. This was followed by a joint call for proposals that was issued in January 2015 by ESA’s Directorate of Science and Robotic Exploration and the Chinese Academy of Sciences (CAS).

Following selection in November 2015, detailed studies by ESA, CAS, three European industrial contractors and the Science Study Team have finalised the mission architecture, including the space and ground elements that are required to fulfil the science requirements.

Under current plans, the 2200 kg spacecraft will be launched by a European Vega-C rocket or Ariane 6-2 in 2023, and subsequently be placed in a highly inclined elliptical orbit around Earth. Every 51 hours, Smile will fly out to 121 000 km – almost one third of the distance to the Moon – giving it a prolonged view of Earth’s northern polar regions. It will then return to within 5000 km of the planet in order to download its treasure trove of stored data to an ESA ground station in Antarctica and the CAS ground station in Sanya, China.