UA’s HiRISE camera marks 20 years of sending postcards from Mars

Over the last 20 years, the HiRISE camera in orbit around Mars has beamed more than 100,000 photos to the UA Lunar and Planetary Lab.

That’s not too shabby for a camera that launched from Cape Canaveral with a planned four-year mission aboard NASA’s Mars Reconnaissance Orbiter in 2005.

Alfred McEwen, an Lunar and Planetary Lab professor who served as principal investigator for the High Resolution Imagining Science Experiment until last year, said it “feels great” to hit the 20-year milestone.

“It’s great to keep going in any form,” said McEwen, who remains involved with HiRISE as principal investigator emeritus. “It’s a little frustrating because they keep cutting our budget and so we don’t have funding really to do science analysis. We just have funding to collect and process the images and archive them and let the rest of the world do the science analysis of them, which they’re doing happily. So that’s good.”

HiRISE principal investigator emeritus Alfred McEwen. Photo courtesy University of Arizona

Over the years, HiRISE images have helped find landing sites for NASA spacecraft including the Phoenix Mars Lander and the Curiosity and Endeavor missions. The camera has been able to capture images of spacecraft as they descended to the planet and made pictures of rovers rolling around the planet.

“We’ve had lots of fun,” McEwen said. “The first descent was on a parachute – the Phoenix lander, which was a UA-led mission. And when that was first suggested, I laughed. Great idea. They’ll never approve it, too risky. But they did approve it, and it actually worked.”

HiRISE images have helped scientists understand what’s happening on the surface of Mars.

“One surprise was learning about the gullies that were much talked about from previous decades as being signs of flowing water today,” McEwen said. “We monitored them and found that they are forming today, all right, but in the winter when there’s CO2 frost on the ground, which buffers the temperature to like 140, 150 Kelvin, way too cold for liquid water. It’s fluidization from CO2, which condenses out of the atmosphere. So that’s a very different process that leads to very similar looking features.”

The HiRISE team takes requests from the public via its HiWish program. Anyone can submit a suggestion about future exploration sites. “We’ve taken over 10,000 images based on HiWish requests now,” McEwen said.

The HiRISE camera before it launched for Mars. Photo by NASA/JPL/Ball Aerospace

The HiRISE camera was designed and built by a team that included McEwen and Alan Delamere of Ball Aerospace & Technologies. It was among the suite of instruments aboard NASA’s MRO, which launched on Aug. 12, 2005, and slipped into Martian orbit in March 2006. After taking a few test photos, it took its first high-resolution photo of Mars on Sept. 29, 2006.

Two decades later, McEwen credited HiRISE’s longevity to “a combination of good planning and luck.”

HiRISE is facing some challenges of old age. Some of the electronics have failed outright and others have been intermittent, resulting in some gaps in the images.

“We can still do all of our science, but we might need to go back and take several images instead of just one to cover the feature of interest,” he said.

HiRISE has enough fuel to last another decade in orbit around Mars and there may be ways to extend that life, McEwen said.

“If we get 10 more years, I’ll be very happy,” he said.

Here are 10 HiRISE photos. Dig into more of them yourself at the UA’s HiRISE website.

NASA/JPL-Caltech/University of Arizona

In February 2012, HiRISE captured an image of a dust devil rising from the planet’s Amazonis Planitia region.

“The length of the shadow indicates that the dust plume reaches more than 800 meters, or half a mile, in height,” wrote HiRISE team member Paul Geissler. “The tail of the plume does not trace the path of the dust devil, which had been following a steady course towards the southeast and left a bright track behind it.”

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NASA/JPL-Caltech/University of Arizona

This image from November 2006 captures eroding layers in an impact crater that stretches about 30 kilometers across.

“In broad view, it is clear that the deposit is eroding into a series of ridges, likely due to the wind,” HiRISE team member Colin Dundas wrote. “Below the ridges, additional dark-toned layered deposits crop out. These exhibit a variety of textures, some of which may be due to transport of material.”

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NASA/JPL-Caltech/University of Arizona

This November 2006 image of layered deposits captures a 3-kilometer-thick stack of dusty water ice layers located in the north polar region.

“The layers record information about climate stretching back a few million years into Martian history,” McEwen and his co-authors Candice Hansen-Koharcheck and Ari Espinosa wrote in “Mars: The Pristine Beauty of the Red Planet,” a hardback collection of HiRISE photos published by UA Press in 2017.

“In many locations, erosion has created scarps and troughs that expose this layering,” they wrote. “The tan-colored layers are the dusty water ice of the polar layered deposits; however, a section of bluish layers is visible below them. These bluish layers contain sand-sized rock fragments that likely formed a large polar dune field before the overlying dusty ice was deposited. The lack of a polar ice cap in this past epoch attests to the variability of the Martian climate, which undergoes larger changes over time than Earth.”

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NASA/JPL-Caltech/University of Arizona

A new impact crater on the surface of Mars that formed sometime between September 2016 and February 2019.

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NASA/JPL-Caltech/University of Arizona

This image, captured in November 2006, shows boulders that are sliding into a crater.

“Most debris on crater walls slides straight downhill,” HiRISE team member Candice Hansen-Koharcheck wrote. “In this HiRISE image we see examples of boulders that have bounced downhill, not necessarily vertically.”

“A prominent example looks like a dotted line from the top of the crater wall where the boulder took off to the crater floor where it finally came to rest,” Hansen wrote. “Numerous boulders have slid partway down toward the crater floor, which is covered by sand dunes.”

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NASA/JPL-Caltech/University of Arizona

HiRISE captured an image of the Phoenix Mars Lander, another UA Lunar and Planetary Lab-led NASA mission, as it descended to Martian north pole in 2008. You can see the parachute that slowed the spacecraft’s descent to the planet’s surface.

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NASA/JPL-Caltech/University of Arizona

HiRISE captured its 100,000th image on Oct. 7, 2025, with this shot of mesas and dunes in Syrtis Major, “a region about 50 miles (80 kilometers) southeast of Jezero Crater, which NASA’s Perseverance rover is exploring,” according to NASA. “Scientists are analyzing the image to better understand the source of windblown sand that gets trapped in the region’s landscape, eventually forming dunes.”

“HiRISE hasn’t just discovered how different the Martian surface is from Earth, it’s also shown us how that surface changes over time,” said MRO’s project scientist, Leslie Tamppari of NASA’s Jet Propulsion Laboratory in Southern California. “We’ve seen dune fields marching along with the wind and avalanches careening down steep slopes.”

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NASA/JPL-Caltech/University of Arizona

Scientists believe this impact crater was created within a decade of HiRISE capturing this image in February 2018.

HiRISE team member Ingrid Daubar wrote that the impact “triggered a slope streak. When the meteoroid hit the surface and exploded to make the crater, it also destabilized the slope and initiated this avalanche.”

“The crater itself is only 5 meters across, but the streak it started is 1 kilometer long!” Daubar wrote. “Slope streaks are created when dry dust avalanches leave behind dark swaths on dusty Martian hills. The faded scar of an old avalanche is also visible to the side of the new dark streak.”

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NASA/JPL-Caltech/University of Arizona

During the warming of Martian spring, jets of gas burst through a layer of dry ice that covers the polar region, carrying dust to the surface.

“The dust gets carried downwind by the prevailing wind and falls on top of the seasonal ice layer in a fan-shaped deposit,” wrote HiRISE team member Candice Hansen-Koharcheck. “Many jets appear to be active at the same time since numerous fans are all deposited in the same direction. At the top of this image, the fans are oriented in one direction while at the bottom they are going in a different direction. This suggests that as the ice layer thins, a set of gas jets becomes active, they die down, then further away another set starts up at a later time with a different prevailing wind direction.”

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NASA/JPL-Caltech/University of Arizona

As a reminder that HiRISE has gone where no man has gone before, there’s this 2019 image from Hellas Planitia.

“Long ago, there were large crescent-shaped (barchan) dunes that moved across this area, and at some point, there was an eruption,” wrote HiRISE team member Ross Beyer. “The lava flowed out over the plain and around the dunes, but not over them. The lava solidified, but these dunes still stuck up like islands. However, they were still just dunes, and the wind continued to blow. Eventually, the sand piles that were the dunes migrated away, leaving these ‘footprints’ in the lava plain. These are also called ‘dune casts’ and record the presence of dunes that were surrounded by lava.”

“Enterprising viewers will make the discovery that these features look conspicuously like a famous logo,” Beyer added, “and you’d be right, but it’s only a coincidence.”