For 20 years, our Mars Reconnaissance Orbiter has searched the planet for signs of long-ago water. It has sent back photos that are not only stunning, but useful – they'll help us when future astronauts land on Mars to explore it. Which is your favorite?

Get to know MRO (Mars Reconnaissance Orbiter): go.nasa.gov/4b1fsqq

@NASA I'm not believing any shit until we have real human on Mars

@NASA There used to be a Video on Youtube with those stunning images of the Mars orbiter but I can't find it anymore. Does anybody know what I mean? Help find it? Those alien shapes are extraordinary.

@NASA All of them!

@NASA Wow, to think there’s a whole universe of unique geologic formations

@NASA The bottom left picture almost looks like an eye, doesn't it? 👀

@NASA My favorite image would be the ancient riverbeds and valleys on Mars, as they provide evidence of water in the past, helping us understand the potential for life on Mars.

@NASA how are craters signs of water btw @grok

@NASA Designed for five years. Still operating at 20. The fact that MRO has enough propellant to keep functioning into the 2030s means it'll likely be there to support the first human missions it helped make possible.

@NASA @grok How successful was this? What did we learn?

@NASA I am going to print these out and hang them in my house!

@NASA Twenty years orbiting another planet and still finding new stories in the dust, MRO is the definition of patience paying off

🔴 The bottom right image is the most significant one scientifically a fresh meteorite impact crater exposing blue grey subsurface material. That blue color is water ice. When MRO photographed this crater shortly after impact, the excavated material hadn't been exposed to Mars' thin atmosphere long enough to sublimate. The ice was still there. Mars isn't dry all the way down. Beneath the rust red surface there is ice, and potentially liquid water under sufficient pressure and heat. Every fresh crater MRO photographs is an accidental drill sample showing us what lies underneath. 20 years of orbital imaging has produced something more valuable than beautiful pictures. It has produced a geological map detailed enough to tell future astronauts exactly where to land, where water ice is accessible within meters of the surface, and where ancient riverbeds once carried liquid water for millions of years. The spacecraft that helps humans survive on Mars was already there. It arrived 20 years early. 📌 Source: NASA MRO mission documentation, HiRISE camera science team, Mars water ice distribution mapping research

@NASA Mars Has a Permanent Ice Mountain That Never Melts

20 years and still sending back masterpieces. 👏 This one is definitely a favorite. ☄️ It's a 30 meter wide crater that didn't even exist until some years ago. The impact was so strong it blasted dark dust out in "rays" for over 15 kilometers. It's a perfect reminder that the solar system is still a very active, moving place. 🌌

@NASA this one

@NASA I love them all. The top two are my favorites. It will be wonderful to learn the geological process that created that topography and what mineral content it has.

@NASA People say Mars exploration is pointless. Yet every mission expands our understanding of how planets including Earth evolve.

@NASA x.com/ARealRocketMan…

@NASA Reality keeps outdoing fiction in the most incredible ways 🌊

@NASA @grok if we found ancient water on Mars does that mean life once existed there?

@NASA Is there life on Mars?

@NASA @nasa #Mars Reconnaissance Orbiter 🛰️

20 years of MRO is insane — HiRISE has given us the sharpest views of Mars ever, spotting ancient river channels, dune avalanches, recurring slope lineae, and water-ice clues that no other orbiter could match. These images aren't just beautiful; they're literally mapping safe landing zones and science targets for Artemis-era human missions. My favorite from the classics: those spider-like araneiforms in the south pole — seasonal CO2 jets carving the surface! What about you — which MRO/HiRISE shot blows your mind most? 🌍→🔴📸 #Mars #MRO #NASA #SpaceExploration

@NASA I love the dune field image. Wind shaped ripples are like Mars writing in sand, and orbiters can spot how those patterns shift over time as the seasons change.

🏛️ Top Candidates for the Best of MRO ​1. The "Mars Heart" (Terra Sirenum) ​Just released for Valentine's Day 2026, this heart-shaped feature is actually a frost-covered dune field in an unnamed crater. It’s a perfect example of how the Martian seasons create fleeting, beautiful art. ​2. Recurrent Slope Lineae (Newton Crater) ​These dark, narrow streaks that appear to "flow" down steep slopes during warm seasons are among the MRO's most famous discoveries. They provided the first compelling evidence that liquid, briny water might still exist on the surface of Mars today. ​3. The Fresh Crater (Sirenum Fossae) ​Captured in 2015, this 1-kilometer-wide crater looks like a blue splash against the red landscape. It shows the incredible power of MRO to track active changes on the planet, helping us understand the current rate of meteorite impacts—crucial for future astronaut safety. ​4. Martian "Spiders" (South Pole) ​These bizarre, spidery troughs are formed by carbon dioxide gas trapped under seasonal ice. They look like something out of a sci-fi film and highlight the dynamic, active nature of the Martian polar caps.

@NASA The H UGE close up shots on the massive dunes of rock show an interesting pattern of weather. Almost looks like the dessert with symmetrical patterns formed

@NASA It seems SpaceX crew will be the first to lay foot on Mars.

@NASA Hard to choose, but the crater in the bottom-left is stunning.

@NASA 20 years of exploration and still stunning 😍 The photos not only inspire, but will guide future Mars missions. Hard to pick a favorite, they’re all incredible! 🚀🔴

@NASA 20 years of staring at rust-colored landscapes, searching for whispers of ancient water. My favorite? The gullies in Newton Crater—they look like water just flowed yesterday. Mars is more alive than we think. 🌌

@NASA Missions like the Mars Reconnaissance Orbiter show how long-term orbital science can shape the future of exploration. The data collected today could directly guide where humans first step on Mars.

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