(The Hill) — Deimos, the smaller of Mars’ two moons, may be more like its planet than we realize.
New, high-resolution views of the tiny moon were recently captured by a United Arab Emirates spacecraft named Hope. Part of the Emirates Mars Mission (EMM), Hope used its onboard instruments to capture never-before-seen views of the space rock.
Mars has two oddly-shaped moons — Phobos and Deimos, which are just 17 miles and 9 miles in diameter, respectively. Their quirky dimensions, diminutive size, and proximity to the asteroid belt have led scientists to believe that both of these rocky bodies were likely captured asteroids.
But thanks to new images beamed back by the Hope orbiter, a new theory is emerging.
“We’re getting the highest resolution [images] ever,” says Hessa Al Matroushi, the mission’s science lead.
The images, which were shared at the European Geoscience Union meeting on April 24, help to strengthen the notion that Deimos formed at the same time as Mars.
Following its launch in 2020, the Hope Mars orbiter arrived at the red planet in 2021 and has spent its time studying the Martian atmosphere. Now that its primary science mission is complete, the spacecraft has enough fuel reserves to start a secondary mission: observe Deimos in detail.
Hope completed its first flyby of the tiny moon on March 10, whizzing by just 60 miles above Deimos’s surface. The only other spacecraft to get that close was NASA’s Viking 2 orbiter in 1977, but it carried more rudimentary cameras and scientific instruments.
During its initial flyby, Hope trained all three of its instruments onto Deimos, studying the moon in different wavelengths to try and determine its composition. Preliminary analysis shows that Deimos is more similar to Mars than to carbon-rich asteroids.
“It looks like Mars more than it looks like an asteroid,” says Al Matroushi, expressing how ecstatic she and her team were when they first saw the images come through. “Mars was in the background and that was just mind-blowing,” she said.
Scientists are not quite sure yet how Deimos formed, but they are convinced that it is more like Mars than an asteroid, and quite different from Mars’ other moon, Phobos. Al Matroushi said that the team did not find an abundance of carbon and organics as they would if Deimos had asteroid origins. “If there were carbon or organics, we would see spikes in wavelengths,” she said. “But the data was very flat.”
Just like our moon, Deimos is tidally locked to Mars, which means that observations of the moon from the planet’s surface or any spacecraft in low Mars orbit would always see the same side of Deimos.
Fortunately for science, Hope has a very elongated orbit that extends to 40,000 kilometers above the planet, which enables the Hope spacecraft to observe and image Deimos’ far side. 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.
Al Matroushi says that Hope’s observations of Deimos will continue through 2024, alongside additional Mars observations.
“We didn’t want to get just a one-time observation of Deimos,” she said. “We knew we wanted more.”