New Images Reveal Deimos, Mars’ Smallest Moon, May Be More Mars-Like Than Previously Thought

Deimos, the smallest of Mars’ two moons, may be more Mars-like than we realize.

This high-resolution view of the young moon was recently captured by the Emirati spacecraft Hope. As part of the Emirates Exploration of Mars (EMM) mission, Hope used the onboard instruments to capture a never-before-seen view of the space rock.

Mars has two oddly shaped moons – Phobos and Deimos, which are 17 miles and 9 miles in diameter respectively. Their odd dimensions, small size, and proximity to the asteroid belt have led scientists to believe that the two rocky bodies are most likely captured asteroids. But thanks to new images emitted by the Hope orbiter, a new theory has emerged.

We get the highest accuracy [images] Hessa Al Matrooshi, the expedition’s science leader, said.

The images released at the European Geosciences Union meeting on April 24 help support the idea that Deimos formed at the same time as Mars.

After launching in 2020, the Hope Mars Orbiter will reach the Red Planet in 2021 and spend its time studying the Martian atmosphere. Now that its primary science mission is complete, the spacecraft has enough fuel reserves to launch a secondary mission: observing Deimos in detail.

Hope completed its first flyby of the young moon on March 10, flying just 60 miles above the surface of Deimos. The only other spacecraft that came this close was NASA’s Viking 2 orbiter in 1977, but it carried more cameras and rudimentary scientific instruments.

During her first flight, Hope trained her three instruments on Deimos, studying the moon at different wavelengths to try to determine its composition. Preliminary analysis suggests that Deimos is more like Mars than a carbon-rich asteroid.

“It looks more like Mars than an asteroid,” said Al Matrooshi, expressing how excited he and his team were when they first saw the image. “Mars is in the background and it’s amazing,” he said.

Scientists aren’t yet sure how Deimos formed, but they believe it is more like Mars than an asteroid, and very different from another Martian moon, Phobos. Al Matrooshi said the team did not find an abundance of carbon and organic matter as if Deimos had come from an asteroid. “If there is carbon or organics, we will see a spike in wavelengths,” he said. “But the data is very consistent.”

Just like our Moon, Deimos is tidally moored to Mars, meaning observations of the Moon from the planet’s surface or any spacecraft in low orbit around Mars will always see the same side of Deimos. Fortunately for science, Hope has a very long orbit that extends 40,000 kilometers above the planet, allowing the Hope spacecraft to observe and photograph the far side of Deimos. These observations will allow the team to analyze differences between the near and far sides of Deimos to expand on what we know about the Moon and Mars.

Observations of Deimos hope to continue through 2024, Matrooshi said, along with additional Mars observations. “We don’t want to see Deimos just once,” he said. “We know we want more.”