In celebrating the 20th anniversary of ESA’s Mars Express, the agency revealed a stunning new mosaic of Mars. While it’s known as the “Red Planet,” this image shows all of its vibrant colors and stunning details like never before. And honestly, I think this is my favorite Mars photo to date!
This mosaic image was taken by the High Resolution Stereo Camera (HRSC) onboard Mars Express. Usually, the HRSC snaps photos from about 300 km above Mars, with each shot covering about 50 km across the surface. But for this unique task, the HRSC took a different approach.
Instead of sticking to the usual routine, the camera gathered 90 photos from higher altitudes – anywhere between 4000 to 10,000 km. This allowed it to capture wider areas, each about 2500 km across. By stitching these images together, the HRSC created a comprehensive global view of Mars.
Typically, such large-scale images help scientists monitor Mars’s weather. But even without weather events, they provide breathtaking views of the Martian surface. The new panorama enhances local color and contrast, revealing variation across the planet’s surface.
In the past, scientists would process Mars images to reduce color variations. However, for this mosaic, the HRSC team took a new route. They referenced each image to a color model based on high-altitude observations. This allowed them to keep the color variations and present Mars in a richer range of colors than ever seen before.
This variety of colors isn’t just stunning to look at. It also gives us clues about what makes up Mars. The planet is most famous for its reddish color, thanks to the high levels of oxidized iron. But this mosaic also shows large, dark, and blue-toned areas. These are fields of grey-black basaltic sands made from volcanic material. The wind shifts these sands around, forming massive dunes and dune fields inside impact craters.
As for the lighter materials, they were weathered by water. The most common of these on Mars, clay and sulfate minerals, stand out as bright spots in the mosaic. The OMEGA spectrometer on Mars Express confirmed their presence. These minerals tell us that liquid water was once present on Mars for a long time, altering rocks over time to form large clay deposits.
Mars Express mission
Mars Express has been orbiting the Red Planet for two decades, snapping images, mapping minerals, studying the atmosphere, and probing beneath the surface. On its journey, it has given scientists incredible insights into how different things interact in the Martian environment. Interestingly enough, it was expected to operate for one Martian year (around 687 Earth days). But it has definitely exceeded expectations, considering that it has stayed up there for 20 long years!
The mission has now been extended until 2026 at least, according to ESA. So I can only say that I really look forward to even more remarkable images and discoveries about Mars in the coming years.