Science & Technology (Commonwealth Union) – Through the ages the need to explore the external universe has led to extensive knowledge that have made current space exploration possible.
A newly launched space mission, proposed and jointly led by researchers from UCL, is set to capture the first-ever images of the outer boundary of Earth’s magnetic shield. The spacecraft lifted off today from Europe’s Spaceport in French Guiana.
Known as the magnetosphere, this protective magnetic envelope shields Earth from the solar wind — a constant flow of charged particles emitted by the Sun. Without it, life on our planet would be exposed to harmful solar radiation.
The mission, named Smile (Solar wind Magnetosphere Ionosphere Link Explorer), will observe this protective region by detecting X-rays produced when solar wind particles collide with Earth’s magnetic field.
Positioned in an orbit approximately 121,000 kilometres above the North Pole, the spacecraft will have a unique viewpoint that enables it to map these X-rays across a vast area of space. This will provide the first comprehensive view of how Earth’s magnetic defences react to incoming solar wind.
Scientists say the mission will improve understanding of the connection between the Sun and Earth, helping to enhance forecasts of space weather events that can threaten astronauts and interfere with GPS navigation, radio networks, and electrical power systems.
Smile is a collaborative mission between the European Space Agency and the Chinese Academy of Sciences, supported by £15 million in funding from the UK Space Agency. On the European side, scientific leadership for the mission has been provided by researchers at UCL’s Mullard Space Science Laboratory (MSSL).
The Soft X-ray Imager (SXI), designed to map Earth’s magnetic shield, was developed by the University of Leicester in collaboration with MSSL (which contributed the electronics), the Open University, and other European partners.
Dr Colin Forsyth of UCL’s Mullard Space Science Laboratory, who serves as co-principal investigator alongside Professor Chi Wang from the Chinese Academy of Sciences, indicated that missions on prior occasions could detect the edge of Earth’s magnetic field only as they moved through it, giving single-point readings. To determine the field’s overall shape and size, we had to average these positions across different conditions. Until now, no mission has ever been able to directly image its boundary.
“With Smile, we will be able to see how our magnetic bubble changes its shape, whether it does this smoothly or in steps, and how it gets squeezed down as eruptions from the Sun pass Earth. We’ve never done anything like this before. We have lots of models and theoretical frameworks but now we get to see what’s going on.”
Alongside being the first mission to study Earth’s magnetic bubble in X-rays, SMILE will also feature an ultraviolet camera, the Ultraviolet Aurora Imager, which will, for the first time, capture the northern lights continuously for up to 45 hours.
The northern and southern auroras occur when Earth’s magnetic bubble traps and guides charged particles from the solar wind toward the poles, providing another way to track the interaction between the solar wind and our planet’s magnetic field.
Dr Forsyth indicated that by combining the X-ray and ultraviolet observations, we can observe not only the energy entering the system but also how that energy is delivered into the upper atmosphere near the poles.
The mission’s two additional instruments, the Magnetometer (MAG) and the Light Ion Analyser (LIA), will monitor the magnetic field and surrounding plasma environment, providing scientists with detailed information about conditions at the boundary of Earth’s magnetic bubble. Calibration testing for the LIA instrument was carried out in the facilities at MSSL, with support from LIA Co-Principal Investigator Dr Georgios Nicolaou.
Dr Nicolaou indicated that the calibration results obtained at MSSL showed excellent consistency with those from the National Space Science Centre of the Chinese Academy of Sciences and they are now eager to begin examining the first measurements returned from space.
