NASA’s Perseverance Rover is on its way to Mars, but 15 years ago, another spacecraft made the same months-long cruise from Earth to Mars, carrying three cameras and a suite of scientific instruments. Data and images from the Mars Reconnaissance Orbiter helped NASA choose the landing sites for rovers and landers like Curiosity, InSight, and Perseverance. Thanks to the MRO, NASA knew where the rovers could land safely, where to do the most interesting science, and where to go next.
Since its arrival in Martian orbit in early 2006, the MRO has given us an unprecedented look at the Martian landscape, gathered a wealth of data on our rocky neighbor’s geology, and monitored its thin but dynamic atmosphere. It’s also helped keep an eye on the landers and rovers on the planet’s surface, provided photos to help with crash investigations when the ESA’s Schiaparelli lander was lost on Mars in 2016, and sent home some truly gorgeous photos that make the dusty red planet feel like a real place.
If there’s a particular place or feature on Mars you’d like a better look at, you can suggest it to NASA at HiWish. NASA takes these suggestions into consideration when it’s deciding what to photograph next with MRO’s High-Resolution Imaging Science Experiment, or HiRISE.
Exposed Bedrock In An Impact Crater
When an asteroid or comet slammed into Mars in the distant past, the impact blasted this 44 kilometer-wide crater in the planet’s rocky surface. The large impact also caused the ground at the center of the crater to rebound upward (picture what happens when you throw a pebble into the water; the water at the center of the splash bounces back upward after the pebble hits). The result is called a complex crater, and that rebound lifted the greenish bedrock in this photo from where it was buried several kilometers beneath the surface. Over time, the terraces at the sides of the crater have collapsed to reveal more of the bedrock.
Walls of Ice And Rock
These steep icy cliffs can be found near both Martian poles. Their sheer faces are walls of water ice nearly 100 meters high.
A Surprise Dust Devil
One day in 2012, HiRISE was just casually taking some photos of the Amazonis Planitia, a swath of flat land in Mars’s northern hemisphere, when it caught this dust devil twisting across the deserted landscape. Based on the length of the shadow it casts, the dust devil is probably about 800 meters tall and 30 meters wide. It’s hard to compare a Martian dust devil to its Earthly counterparts, because the Martian atmosphere is so much thinner that even a relatively high wind doesn’t actually exert much force.
The Devil’s Tracks
Another dust devil in Mars’ southern hemisphere left these tracks in early 2019, reminding us that Mars is a planet with active weather and a constantly evolving surface.
The Storm That Killed The Opportunity Rover
Although the Martian winds don’t pack a huge punch, potential travelers should still take weather reports on Mars seriously, because the planet’s dust storms kick up a lot of electrical activity – and then there’s the dust itself. Check out these images of Mars taken before and after a dust storm shrouded the planet in dust and dimmed the Martian skies back in the summer of 2018.
Farewell, Little Space Robot
MRO captured this image of the Opportunity Rover in September 2018. NASA wasn’t able to regain contact with the rover after the storm passed; unfortunately, the rover ran out of power thanks to all the dust covering its solar panels and blotting out the sky.
Sand And Ice At The North Pole
The polar landscapes of Mars are a sight to behold. Sand dunes march across the frozen ground during the summer months, and in the winter they’re held in place by a thin layer of frost. The streaked texture on the icy ground between the dunes is a fascinating geological trick called frost heave. If you look closely, you can see piles of boulders scattered here and there along the dark streaks on the ground. NASA explains, “In the Arctic back on Earth, rocks can be organized by a process called ‘frost heave.’ With frost heave, repeated freezing and thawing of the ground can bring rocks to the surface and organize them in piles, stripes, or even circles.”
The Highest Point On Mars
In this image, you’re looking straight down at the 21 kilometer-high peak of the volcano Olympus Mons. Geological evidence suggests the volcano first formed more than 3 billion years ago during the Hesperian Period, when the surface of Mars was a tumult of volcanic eruptions and massive floods. Over time, lava flows built Olympus Mons into a mountain more than twice the height of Mount Everest; the youngest lava flows on its slopes probably date to just 2 million years ago. The dark sediment piled around the foot of the mountain came from landslides rolling down off the mountain’s sides.
An Ancient Flood
In the distant past, Mars had oceans, lakes, rivers, and occasional catastrophic megafloods. When the waters of the Uzboi Valles breached the rim of Holden Crater, the flood dropped 100 meter-wide blocks of stone into the crater. The bright layers you can see on the exposed sides of the rock probably record a much warmer, wetter period of Martian history – which is why NASA once had Holden Crater on its list of possible lander targets.
Curiosity Climbs A Mountain
The MRO captured this shot of its sibling Curiosity trekking its way across a clay-bearing area on the slopes of Mount Sharp back in May 2019, which seems like a century ago now.