Summary
By the end of this article, you will understand how a satellite the size of a milk carton captured the first nanosatellite image of the Northern Lights, and why viewing auroras from space sideways changes everything.
Quick Facts
Surprise: The Suomi 100 satellite is a 1-Unit CubeSat, measuring just 10x10x10 cm (the size of a Rubik's cube)
Salient Idea: The best way to photograph faint space weather is to look sideways at the Earth's horizon (the limb) against the blackness of space
Surprise: The satellite spins constantly, meaning its camera rotated 7.2 degrees during the 2.4-second aurora exposure
Surprise: Ground cameras entirely missed this aurora because of clouds and geography, proving the value of space-based imaging
The Discovery: A 10-Centimeter Photographer
In late 2018, a tiny box called Suomi 100 launched into orbit. It was a 1-Unit CubeSat, a low-cost satellite no bigger than a grapefruit, built mostly with commercial off-the-shelf parts. In January 2019, its simple 3-megapixel camera snapped a picture. Because the satellite’s data rate is incredibly low, researchers initially only saw a tiny, pixelated thumbnail. But upon closer inspection, they found a Surprise: the first-ever image of the Northern Lights taken by a nanosatellite. The image was slightly blurred because the satellite was tumbling, rotating constantly through the dark. To figure out what they were actually looking at, the team had to act like forensic detectives. They combined the satellite image with data from ground-based magnetometers across Scandinavia. Ground cameras saw nothing, proving exactly why this space-based view was so revolutionary. They had captured a ghost storm.
The analyzed image is, to the authors’ best knowledge, the first auroral image ever taken by a cubesat.
— Esa Kallio et al.
The Science Explained Simply
This is NOT like setting up a camera on a tripod in your snowy backyard. When you take a picture of an aurora from the ground, you are looking straight up through miles of thick, distorting atmosphere, and your view is easily blocked by clouds. The Salient Idea here is ‘limb-viewing geometry.’ Instead of pointing straight down at the ground (nadir), the Suomi 100 camera looked sideways, toward the edge (limb) of the Earth. Against the pitch-black background of empty space, even the faintest auroral emissions stand out brilliantly. To make sense of the photo, researchers built a 3D virtual model to trace where the red and green photons originated. They discovered the aurora was likely hovering high over the North Sea or Greenland, entirely out of sight from normal ground stations.
The Aurora Connection
Auroras are the ultimate visual evidence of Earth’s magnetic field battling the solar wind. When high-energy particles from space smash into oxygen and nitrogen in our upper atmosphere, they emit vibrant colors. But observing this from the ground only gives us a flat, bottom-up perspective. To truly understand these massive geomagnetic storms, scientists need tomographic (3D) imaging. Tiny nanosatellites like Suomi 100 are the missing puzzle piece. By flying right above the ionosphere, these CubeSats look at the vertical structure of auroral curtains from the side. This unique perspective helps us map the exact altitudes where different gases are energized, revealing the true power and shape of the invisible magnetic forces protecting our planet.
Synthetic images based on the intensity model showed that the location where the auroras were observed were ideal for auroral photography from space.
— Research Team
A Peek Inside the Research
How do you locate a glowing light in a photo taken from a spinning box traveling at 7 kilometers per second? It comes down to Knowledge and Tools—specifically, brilliant computational modeling. The team didn’t just guess; they built a Virtual Pin-Hole Camera simulation. They generated millions of fake ‘photon emission points’ in a 3D computer model, simulating green auroras at 110 km high and red auroras at 230 km high. By matching the stars in the background of the real photo (like the star Altair) and comparing the pixel intensities of their 3D model to the real image, they could mathematically triangulate the aurora’s true position. It is a triumph of using brilliant software engineering to enhance simple hardware.
The data analysis and modelling demonstrate how even a small 1-Unit CubeSat… can open new possibilities for auroral research.
— Esa Kallio et al.
Key Takeaways
Space-based cameras bypass the biggest enemies of aurora hunters: clouds and thick atmospheric distortion
A 3D computer simulation can be used to reverse-engineer the 3D location of an aurora from a single 2D photograph
Nanosatellites prove that you don't need billion-dollar budgets to do real, valuable space weather science
Combining ground-based magnetic sensors with space cameras gives a complete, multi-layered picture of an auroral storm
Sources & Further Reading
Frequently Asked Questions
Q: Why use a tiny satellite instead of a big, expensive space telescope?
A: Tiny CubeSats are incredibly cheap to build and launch using off-the-shelf parts. In the future, launching swarms of them could give us simultaneous 3D views of auroras from dozens of angles at once, something a single billion-dollar satellite cannot affordably do.
