Space travel Smile: Understanding Solar Storms, Geomagnetic Storms, and Space Weather

On May 19, 2026, the Smile space probe launched with a Vega-C rocket from the European Spaceport in French Guiana. Smile, a joint project of ESA and the Chinese Academy of Sciences, aims to demonstrate how Earth responds to particle streams and radiation bursts from the Sun.

Solar Wind Magnetosphere Ionosphere Link Explorer, or Smile, will utilise four scientific instruments to investigate how the Earth responds to the solar wind. In this way, Smile will enhance the understanding of solar storms, geomagnetic storms, and the science of space weather. The ESA is responsible for providing Smile's payload module, one of the spacecraft's four scientific instruments, namely the Soft X-ray Imager (SXI), the launch vehicle, as well as the facilities and services for assembly, integration, and testing. The ESA also contributes to a second scientific instrument, the Ultraviolet Imager (UVI), as well as to mission operations once Smile is in orbit.

The Chinese Academy of Sciences (CAS) provides the other three scientific instruments as well as the spacecraft platform and is responsible for operating the spacecraft in orbit.

"We are on the verge of witnessing something we have never seen before—the Earth's invisible protective shield in action," explains ESA Director General Josef Aschbacher. "With Smile, we are pushing the boundaries of science to answer big questions that have remained a mystery since our discovery over seventy years ago that the Earth is safely enclosed within a giant magnetic bubble." David Agnolon, Smile Project Manager at ESA, adds: "Smile will shed light on the mysteries of Earth's magnetic field. The mission is made possible through seamless collaboration between ESA and CAS, with contributions from partners across Europe. It is the first time that ESA and China have jointly selected, designed, implemented, launched, and operated a mission, and we are all very excited about the significant scientific discoveries we expect from Smile over the next three years."

How does the defence against the solar wind work?

For nearly four billion years, the Earth has maintained a massive shield against the relentless onslaught of charged particles from the Sun. This solar wind can damage everything in its path, especially when it intensifies into solar storms. The solar wind would turn the green and blue Earth into a rocky, brown wasteland—if not for the magnetic field generated deep within our planet. This magnetic field forms a giant protective bubble around the Earth, the magnetosphere.

For the first time in history, humanity has reached a point where scientific instruments and technologies have advanced enough to clarify how this defence against the solar wind works. Smile is equipped with a set of instruments designed to provide a comprehensive insight into how Earth's magnetic field responds to the relentless assaults of the Sun.

The Earth's magnetic field is being observed with X-ray vision to reveal where and how it is struck by the solar wind. This interaction triggers disturbances—from small substorms to major geomagnetic storms—that spread through the magnetosphere toward the North and South Poles. There, the magnetic storms create a light spectacle, the aurora. Smile will record the northern lights using ultraviolet radiation for 45 continuous hours, making it the first mission to observe them for such a duration and the first since 2008 to observe the entire auroral oval around the North Pole in ultraviolet light.

By comparing the X-ray and ultraviolet images, it is possible to track in real-time how the Earth reacts to the onslaught of the solar wind.

Data collection begins in July

Over the course of the next month, Smile will slowly gain altitude through eleven engine ignitions and eventually settle into an extremely elliptical orbit, taking it 121,000 km (approx. 75185 miles) over the North Pole to collect data before descending to 5,000 km (approx. 3107 miles) over the South Pole to efficiently transmit this data to the eagerly awaiting scientists on Earth.

Data collection will begin in earnest in July after the team has deployed the booms, opened the camera covers, and confirmed that everything is functioning as expected.

Collaboration made in Europe

Smile is an international project with significant European contributions. On behalf of the ESA, Airbus Defence and Space in Spain has built the payload module of Smile. This crucial part of the spacecraft houses three of the mission's four scientific instruments—including the X-ray and ultraviolet cameras, as well as the control unit for the instruments and the communication channel through which all valuable scientific data is transmitted back to Earth.

Europe was also responsible for the X-ray camera, Smile's largest instrument. On behalf of ESA, this camera was developed and built in the UK by the University of Leicester in collaboration with the Mullard Space Science Laboratory, the Open University, and several other institutions across Europe.

A total of institutes and companies from 14 European countries were involved in the development of the payload module and the X-ray camera, with the United Kingdom and Spain making the largest contributions.

The ESA's financial contribution to the mission amounts to 130 million euros (approx. 150 million USD) and includes over 25 procurement contracts with more than 40 companies and institutes. All ESA member states make an indirect contribution through the agency's science program, with the average contribution to Smile being around 28 cents per European resident. (se)