Smile, the joint mission between the European Space Agency and the Chinese Academy of Sciences, is ready to get down to its real work. ESA announced on 30 September that the spacecraft was declared ready for science operations on 23 September, after about three months of commissioning in orbit.

Smile's job is to show how Earth's magnetic field copes with the solar wind, the stream of charged particles that pours off the Sun. Along with the news, ESA put out the mission's first ultraviolet footage of the northern lights and the first two test images from its brand-new X-ray camera.

From launch to a science licence

Smile (short for Solar wind Magnetosphere Ionosphere Link Explorer) lifted off on a Vega-C rocket from Europe's Spaceport in French Guiana on 19 May. That's the same European rocket that carried FLEX and Sentinel-3C into orbit in September. There was an Australian link on launch day, too. ESA's New Norcia ground station, north of Perth, picked up Smile's first signal after it separated from the rocket.

Photo: European Space Agency / Wikimedia Commons (CC BY-SA 3.0 IGO), cropped

Over the next month the spacecraft raised its own orbit with 11 engine burns. It ended up in a long, stretched-out loop. At the top it climbs about 121,000 km above the North Pole to collect data. Then it swings down to about 5,000 km over the South Pole to send that data home. Smile reached that science orbit on 20 June.

Then came commissioning. ESA says the European and Chinese teams spent the time since 20 June deploying mechanisms, switching on units, checking every communications link between the spacecraft and the ground, and fixing problems as they cropped up. "A spacecraft never quite behaves the same in space as it does on the ground," the agency wrote.

Carole Mundell, ESA's Director of Science, put it this way in the release: "Smile is now approved to begin science operations. This is a very important milestone – a true pleasure to announce – and I am sure our excellent collaboration will deliver ground-breaking data to scientists around the world."

What the aurora camera has already seen

Smile carries four science instruments. There's a soft X-ray imager, an ultraviolet aurora imager, a magnetometer and a light ion analyser. Right now, the ultraviolet camera is the one with pictures to show.

ESA's first UVI release covers just under an hour, from 00:00 to 00:58 Universal Time on 24 July 2026. That was about two weeks after the camera was switched on. You see Earth as a light blue disc with a swirling white ring around the North Pole. That ring is the aurora. The way it ripples tells scientists a substorm was going on in Earth's magnetosphere.

ESA describes substorms as brief disturbances. They happen when the solar wind squashes Earth's magnetic field lines, forcing them to pinch together and fire a burst of energetic particles towards the poles. That's what lights up the northern and southern lights. The agency expects about 300 substorms over Smile's planned three-year mission. It says they're more common than usual right now, because the Sun is at the busiest point in its 11-year cycle.

The headline numbers belong to this camera. According to ESA, Smile is the first spacecraft since 2008 to capture the full ring of northern lights around the North Pole in ultraviolet light. It's also watching the aurora for 45 hours at a time, which the agency calls a record. Those long stares come down to that lopsided orbit. It keeps the spacecraft hanging high over the Arctic for most of each loop.

The X-ray camera's first light

The soft X-ray imager, or SXI, is Europe's biggest single contribution to the mission. It was built in the UK by the University of Leicester with Mullard Space Science Laboratory and the Open University, working with other institutions around Europe.

Its real target is something no spacecraft has imaged in detail before. That's the magnetopause, the boundary where the solar wind slams into Earth's magnetic field and gives off faint X-rays. For its first test shots, though, the team pointed it at two well-known exploded stars that glow brightly in X-rays.

One image shows N132D, a supernova remnant in the Large Magellanic Cloud about 160,000 light-years away. The other shows Cassiopeia A, about 11,000 light-years away. ESA says both were taken to check the camera works as it should, and that it's working very well.

ESA's update does come with one honest catch. When SXI points towards Earth, it's picking up too much stray light at the moment. The agency says ESA, the instrument team and the Chinese team running the spacecraft are changing settings and uploading software to cut that down. The camera was designed so they can tweak it remotely.

Nature's lending a hand as well. Smile is pointing steadily farther from Earth, and the North Pole gives off less light as the northern winter comes on. ESA expects the stray light to bottom out in mid-October. That's when it hopes SXI can take its first good image of the magnetopause, or of the northern polar cusp. The cusp is a gap in the magnetosphere above the North Pole where solar wind particles get funnelled down towards the surface. Mid-October is a goal, though, not a confirmed date.

Why space weather watchers care

Earth's magnetic field forms a protective bubble called the magnetosphere. When solar storms hit it, you can get bright auroras. You can also get trouble for satellites, radio links and power grids. The idea behind Smile is to watch both ends of that chain at once. The X-ray camera sees where and how the solar wind hits the magnetic shield, and the ultraviolet camera watches the aurora that follows.

"The evidence that Smile collects will help us better understand planet Earth and our Solar System as a whole," ESA Smile Project Scientist Philippe Escoubet said at launch. "And the science it uncovers will improve our models of Earth's magnetic environment, which could ultimately help keep our astronauts and space technologies safe for decades to come."

The magnetometer and light ion analyser fill in the local picture. They measure the magnetic field and charged particles right where the spacecraft is flying. Europe and Japan will soon ask the same kind of question about another planet. BepiColombo is six months from Mercury orbit, and JAXA's Mio orbiter is headed for a polar ellipse to study Mercury's magnetic field.

A first for Europe and China

Smile's also a first in how it came together. At launch, ESA project manager David Agnolon said it was the first time ESA and China had jointly selected, designed, implemented, launched and operated a mission together.

The split of work is clear. ESA provided the payload module, which carries three of the four science instruments and was built for ESA by Airbus Defence and Space in Spain. ESA also supplied the X-ray camera, the launch and the assembly and testing facilities, and it chips in on the ultraviolet camera and mission operations. CAS provided the other three instruments and the spacecraft platform, and it runs the spacecraft in orbit.

To mark the start of science, ESA has posted a documentary, Let's Smile (the full story), on its official YouTube channel. It follows the spacecraft from June 2024 to May 2026, as the parts arrived at ESA's technical centre in the Netherlands, got put together and tested, and were shipped to French Guiana for launch.

ESA says Smile went from a handful of separate pieces to collecting science data in just over two years. The next thing to watch for is that first clean X-ray view of Earth's magnetic shield. ESA's aiming for it once the stray light bottoms out in mid-October, if things go to plan.