It’s not only Instagram users and holiday makers snapping selfies — even robots are getting in on the action. This new image from the NASA Perseverance rover shows a selfie that’s out of this world, captured as the rover collected its latest sample of martian rock.
Taken on May 10, the selfie was devised to celebrate the rover’s 1,500th day on Mars. As a day on Mars is just a little bit longer than an Earth day, at around 24 hours and 39 minutes, NASA measures its Mars missions in “sols” or martian days. As well as being a fun image for scientists and the public to enjoy, it gives the engineering team on the ground the chance to check the look and the status of the rover as it has been exploring since it landed in February 2021.
You can see plenty of red dust covering the rover, as the surface of Mars is covered in a dusty material called regolith which gives the planet its famous red color. Dust can be quite the challenge for Mars missions, as it gets everywhere when it is whipped up by huge dust storms and can cause problems by gumming up electronics and covering solar panels. But fortunately for Perseverance, the rover may look a little grubby on the outside but its essential functions are all still working well.
“After 1,500 sols, we may be a bit dusty, but our beauty is more than skin deep,” said Art Thompson, Perseverance project manager at NASA’s Jet Propulsion Laboratory. “Our multi-mission radioisotope thermoelectric generator is giving us all the power we need. All our systems and subsystems are in the green and clicking along, and our amazing instruments continue to provide data that will feed scientific discoveries for years to come.”
Even with all the instruments working correctly, though, getting the rover to take a selfie isn’t a quick job. The image was captured using Perseverance’s WATSON (Wide Angle Topographic Sensor for Operations and eNgineering) camera, which is located at the end of its robotic arm. As the rover was working on capturing the selfie, it also caught an unexpected photobomber: a wind feature called a dust devil which popped up in the background.
“To get that selfie look, each WATSON image has to have its own unique field of view,” explained Megan Wu, a Perseverance imaging scientist from Malin Space Science Systems. “That means we had to make 62 precision movements of the robotic arm. The whole process takes about an hour, but it’s worth it. Having the dust devil in the background makes it a classic. This is a great shot.”
With its celebrations well in hand, the rover is now moving on to investigate a new area of Mars: a region called “Krokodillen” after a Norwegian mountain ridge. This area is particularly exciting because it is thought to contain some of the oldest rocks on Mars, which could help to unlock the secrets of how the solar system formed.
Here on Earth, our planet has a system of tectonics in which parts of the planet’s crust are gradually pulled down toward the mantle when they meet at a fault line. That means that the rocks on Earth are essentially recycled in an ongoing cycle of melting down toward the planet’s interior then rising up and cooling to become part of the surface. That’s why there are very few extremely old rocks on Earth.
On Mars, however, it’s a different story. Mars doesn’t have plate tectonics, so very old rocks can stay on its surface for billions of years. Some of these are up to 4 billion years old, or even older, so studying them can help scientists learn about how the rocky planets formed in our solar system around 4.5 billion years ago.
To study these very old rocks, though, Perseverance needs to find them first. There are thought to be extremely old rocks along the edge of the huge crater in which the rover landed, called Jezero. The Jezero Crater is almost 30 miles across, likely created by a huge meteorite impact billions of years ago. When this object slammed into the martian surface, it threw up large amounts of material like huge chunks of rock which landed nearby and are still there to this day.
That means that by looking along the rim of the crater, Perseverance can search for these ancient chunks of rocks and use its instruments to study them. That can also help to answer one particularly important question that scientists want to understand, which is how long there was water on Mars. They know that, although Mars is dry and arid today, it once had plentiful liquid water on its surface. It may even have looked a lot like Earth at one point — and we know that water is essential for the formation of life.
What scientists don’t agree on is exactly how long there was water on Mars, and whether it would have been around for long enough to give potential life the chance to develop there. So knowing exactly when Mars lost is water is a key part of understanding the planet and whether it could ever have supported life.
To that end, Perseverance will be keeping a lookout for clay minerals which form in the presence of water, perhaps even formed before the impact which created the crater. These could contain potential indications of life, called biosignatures, such as organic compounds.
“If we find a potential biosignature here, it would most likely be from an entirely different and much earlier epoch of Mars evolution than the one we found last year,” said NASA scientist Ken Farley. “The Krokodillen rocks formed before Jezero Crater was created, during Mars’ earliest geologic period, the Noachian, and are among the oldest rocks on Mars.”
