We’ve seen our share of photos of Mars from orbit and the surface, but what about its moons? The United Arab Emirates Hope orbital mission to Mars sent home new beautiful high-resolution images of the Red Planet’s moon Deimos when it flew within 100 km of the moon last month. This is the closest any spacecraft has been to Deimos in almost 50 years.
In the photos, the science team says that their images of Deimos help provide evidence that the moon wasn’t a captured asteroid but came from Mars itself during an impact in the ancient past, much like Earth’s Moon.
In our lead image, Deimos is seen orbiting 20,000 km above Mars, a stunning view. It almost looks like Deimos is about to crash into Mars! (It’s not).
The images were taken on March 10, 2023 by the spacecraft’s EXI Digital Exploration Camera.
On Twitter, the Hope mission team said the camera obtained 27 images of Deimos over the course of 25 minutes thanks to a close flyby of Deimos.
“Many defects caused by the camera system have been removed, and contrast and brightness have been adjusted to improve the overall visibility of the Deimos surface.”
Its long been thought that Mars’ two moons, Phobos and Deimos, are captured asteroids. These two potato-shaped moons are among the smallest in the solar system: Deimos measures 12.6 km (7.8 mi) across, and Phobos has a diameter of 22.2 km (13.8 miles). Both are lumpy, heavily-cratered and covered in dust and loose rocks. The reason they are thought to be captured asteroids is because they are among the darker objects in the solar system and appear to be made of carbon-rich rock mixed with ice.
Deimos takes 30 hours for each orbit around Mars, while Phobos, with an orbit only 6,000 km (3,700 miles) above the Martian surface, whips around Mars three times a day.
Another instrument on the Hope spacecraft, EMIRS, a Fourier Transform Thermal Infrared spectrometer, also captured infrared spectral data of nearly the entire surface of Deimos.
On Twitter, the team said, “These results support the interpretation that Deimos may be formed of coalesced pieces of Mars perhaps ejected from a large impact rather than a captured carbonaceous D-Type asteroid.
“The observed surface temperatures indicate the possibility of freezing of volatile materials at the poles of “Deimos”, and the almost inhomogeneity of the surface, in addition to the possibility that it contains fine and coarse sand grains measuring centimeters.”
“The infrared spectral data also shows a similarity with data from Mars’ largest moon, Phobos, and indicates a basaltic origin for the formation of the moon. These results support the hypothesis that Deimos may be composed of cohesive pieces of Mars that were likely the result of a large collision.”
The team said their data indicates that instead of a Deimos being rocky asteroid, they think it came from Mars itself after an impact, and then was pulled it into its orbit. This is likely to be debated, with future data and additional study needed.
The science team also indicated that Phobos will also be studied by their instruments in an upcoming flyby.
Well done to the Hope mission team! We need to learn more about Mars’ natural satellites. I wonder if they will one day become useful as waystations either to the Martian surface or beyond.