Today, during a signature ceremony, ESA announced that the Smile mission will be launched on board a Vega C rocket, from Europe’s Spaceport in late 2025. Solar wind Magnetosphere Link Explore (Smile) is the result of an unprecedented collaboration between the European Space Agency and the Chinese Academy of Sciences (CAS).
The satellite will study, like never before, Earth’s magnetic environment, building a more complete understanding of the Sun-Earth connection. The choice of the Vega C could be a sign of confidence from both ESA and Arianespace in a return to operation by the end of 2024 for the Avio launcher, which has been inactive since 2022.
“Today marks a major milestone for our innovative Smile mission and signals the determination of all our teams and partners to deliver a successful mission on schedule for maximum scientific benefit.”
— Prof. Carole Mundell, ESA Director of Science
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A European-Chinese mission
Smile was selected in 2015 from a pool of 13 potential missions under a joint ESA-CAS call. In 2023, the mission’s Critical Design Review was completed and in October 2024 the section of the spacecraft from Europe and China will be integrated at the European Space Research and Technology Centre (ESTEC) in Noordwijk, Netherlands.
As the name suggests, the mission will focus on improving our understanding of the interactions between the solar wind and the Earth’s magnetosphere. When charged particles, ejected at high speeds from the Sun, collide with the Earth’s magnetic field, they produce disturbances in the magnetosphere. Once these particles ionize in the upper atmosphere, they give rise to the fascinating and famous phenomenon of the aurora. Smile will investigate these events as never been done before.
To do so the spacecraft will take advantage of a particular orbit and a new technique, already demonstrated by ESA’s XMM-Newton. As part of the “solar wind charge exchange” method, Smile will detect the X-ray light emitted when solar wind particles interact with neutral particles in Earth’s upper atmosphere.
To complement these data the satellite will continuously image the auroras in ultraviolet. Thanks to a highly elliptical orbit, Smile will spend much of its time at high altitude, allowing continuous observation for more than 40 hours. At apogee, the spacecraft will reach a distance of 121,182 km, one-third of the way to the Moon. Vega C will insert the satellite into low earth orbit. A propulsion module will then push it to the nominal orbital.
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Vega C: a complex return to flight
If the preparation schedule for the Smile satellite is clear and in line with the expected timing, there are still many doubts about the return to flight of the Vega C. The small-lift rocket developed and operated in collaboration by the Italian Avio and Arianespace, has been grounded since the failed VV-22 mission, in December 2022.
An independent investigation conducted by the ESA has indicated that the cause of the incident was a “thermo-mechanical over-erosion” of a component of the Zefiro-40 solid-fuel second stage. The failure caused the loss of two Airbus Pléiades Neo imaging satellites.
Moreover, a failure during a Z40 static-fire test in June 2023 further postponed the launcher’s return to service. Following further internal investigation, ESA established that the motor nozzle would need to be entirely redesigned. Now Vega C is officially expected to lift off again not before November 2024 to carry the Sentinel 1C Earth observation satellite.
Despite these failures, Avio and Arianespace aim to conduct several launches of the Vega C in the coming years, with five missions planned for 2025 alone. This ambitious schedule will depend on the two key static-fire tests planned for this year.
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