NASA’s Perseverance rover doesn’t only spend its time looking down at the rocks and dust that cover the surface of Mars. It also looks up, and recently it captured an image of Mars’ tiny moon, Deimos, hovering overhead in the Martian sky.
Deimos is the smaller of Mars’ two moons, along with its bigger companion, Phobos, and measures less than 2 miles across. It is covered in impact craters from asteroid strikes, and it’s also covered in dust that gives it a smoother appearance than Phobos.
NASA shared the following image captured by the rover looking up, which zooms in to show the tiny bright white dot of Phobos passing through the sky:
Sky watching is fun no matter where you are. I took this short time lapse movie to watch for clouds, and caught something else: look closely and you’ll see Deimos, one of two moons of Mars.
— NASA's Perseverance Mars Rover (@NASAPersevere) August 20, 2021
A particularly intriguing concept about Mars’ moons is that they could once have been rings, like those around Saturn. Over thousands of years, the material in these rings condensed into the two moons we see today. And the moons might not be around forever — one theory states that eventually Phobos will come too close to Mars and break apart into tiny pieces, becoming a set of rings. This may even operate as a cycle, with Mars switching between rings and moons over millennia.
Mars’ moons have also been in the news recently as Japanese scientists suggested that Deimos’ companion, Phobos, may be the ideal location to search for signs of ancient life. Although the moon itself lacks atmosphere and water, making it unsuitable for hosting life, it could carry evidence if there was once life on Mars. Asteroid strikes on the Martian surface have sent material flying onto Phobos, and its sterile environment could preserve these signs long-term.
We’ll learn more about Phobos and Deimos soon, as the Japanese space agency (JAXA) will be sending its Martian Moons eXploration (MMX) probe to visit them both. The plan is for the probe to land on Phobos and collect a sample to return to Earth, and it will also perform a flyby of Deimos on its way. The mission aims to launch in 2024.