Martian Green Nightglow Seen for the First Time

Artist's impression of the ExoMars Trace Gas orbiter spotting daylight green oxygen at Mars. Credit: ESA

On Earth, there is a phenomenon known as nightglow, where the atmosphere experiences faint light emissions that prevent the night sky from becoming completely dark. This is caused by various processes in the upper atmosphere, like the recombination of atoms, cosmic rays striking the atmosphere, or oxygen and nitrogen interacting with hydroxyl a few hundred kilometers from the surface. Thanks to data obtained by the ESA’s ExoMars Trace Gas Orbiter (TGO), the same phenomenon has been observed in the Martian atmosphere for the first time.

While scientists have long suspected that Mars also experiences this atmospheric phenomenon, this is the first time that effectively proves it. The revelation was made by an international team of scientists based on their analysis of data from the TGO’s Nadir and Occultation for MArs Discovery (NOMAD) spectrometer. When astronauts and rovers explore Mars’ polar regions in the near future, they will see a green glow whenever they look up at the sky and could even use the glow to navigate and find their way in the dark of night.

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Over 100 Million Years Ago, Olympus Mons Had a Massive Landslide

This image from ESA’s Mars Express shows the wrinkled surroundings of Olympus Mons, the largest volcano not only on Mars but in the Solar System. This feature, created by previous landslides and lava-driven rockfalls, is named Lycus Sulci. Credit: ESA/DLR/FU Berlin.

While the surface of Mars looks relatively unchanging now, it wasn’t always so. The tallest mountain in the Solar System is Olympus Mons, a giant shield volcano on Mars that reaches 21.9 km (13.6 miles) high, 2.5 times higher than Mount Everest here on Earth. Ancient lava flows surround the volcanic caldera, evidence of an active time.

New images from ESA’s Mars Express show how these lava flows created extremely sharp cliffs, as high as 7 km (4.3 miles) in some areas, which suddenly collapsed in mind-boggling landslides. One of these landslides occurred several 100 million years ago when a chunk of the volcano broke off and spread across the surrounding plains. If we could look back in time and see as it happened, it was certainly a very dramatic and turbulent epoch on Mars.

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Missed the Mars Livestream? Here's the Video

An animation created from images that were sent to Earth, beamed directly from the Visual Monitoring Camera (VMC) on board ESA’s long-lived Mars Express mission, during a special livestream of data from Mars to celebrate the 20th anniversary of the mission. Credit: ESA.

When a mission to Mars reaches 20 years of service, that’s definitely reason to celebrate. ESA’s Mars Express celebrated by airing the first-ever livestream of images, sent directly from the Visual Monitoring Camera (VMC) on board the spacecraft. For an hour, it sent back images from the Red Planet in as close to real-time as the speed of light would allow.

The animated gif, above, was created from all the images that came down during that hour, roughly 50 seconds apart from each other. There’s a short break in the middle of the animation because of an unexpected rainstorm at ESA’s ground station in Cebreros, Spain, where telemetry wasn’t able to be received.

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20 Years of Mars Express Images Helped Build This Mosaic of the Red Planet

Color mosaic image of Mars, taken by the HRSC instrument aboard the ESA's Mars Express orbiter. Credit: ESA/DLR/FU Berlin (G. Michael)

The Mars Express orbiter, the European Space Agency’s (ESA) first interplanetary mission, entered orbit around Mars on June 2nd, 2003. Since then, the probe has mapped the Martian surface using its High-Resolution Stereo Camera (HRSC), an instrument built by the German Aerospace Center (DLR) with commercial partners. In honor of the mission’s 20th anniversary, a celebration occurred last Friday (June 2nd) at the ESA’s European Space Operations Center (ESOC) in Darmstadt, Germany.

During the festivities, a series of global color mosaic images were live-streamed from the Mars Express orbiter to Earth. The mosaic is the result of a high-altitude campaign conducted by the HRSC science team and state-of-the-art image processing. The result is a mosaic unparalleled in detail, spatial resolution, and diversity of color that provides valuable insight into the Martian environment. This includes revealing the surface composition, demonstrating how water once flowed there in the past, and modern meteorological phenomena.

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New Photos Show Collapsed Chains of Craters on a Martian Volcano

This image from ESA’s Mars Express shows the southern flanks of Ascraeus Mons, the second-tallest volcano on Mars. Credit: ESA/DLR/FU Berlin,.

Most everyone is familiar with Olympus Mons, the largest volcano on Mars and also the largest in the Solar System. But there are several other enormous shield volcanoes on Mars. The second largest is Ascraeus Mons, and new images from ESA’s Mars Express spacecraft reveal some interesting features on the side or flank of the mountain.

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Many Clouds on Mars are Driven by Dust, not Water

One of the benefits of having a cluster of satellites orbiting another planet is that scientists can then analyze that planet’s weather. Sometimes in that process, they find patterns that are strikingly similar to those found on our home planet. That was the case recently when a group of scientists from ESA used data from Mars Express to analyze cloud formation on Mars. To no one’s surprise, dust seemed to be at the core of that formation. But the resultant clouds looked very much like those found here on Earth – in the tropics. 

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Mars Express Watched Deimos Pass in Front of Jupiter and its Moons

Deimos
Deimos, as seen by Mars Express. Credit: ESA.

That’s no moon … wait … yes, it is, and more!

ESA’s Mars Express has captured an unusual and rare occultation, all from its vantage point in orbit of Mars.  The spacecraft’s orbit brought it to the right place where it could witness the moment Mars’ small moon Deimos passed in front of Jupiter and its four largest moons. Scientists say that celestial alignments like these enable a more precise determination of the Martian moons’ orbits.

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Underground Liquid Water Detected on Mars? Maybe not

This image from NASA’s Mars Reconnaissance Orbiter shows the edge of the Martian South Pole Layered Deposit. Credit: NASA/JPL-Caltech/University of Arizona

When planning crewed missions to Mars, the key phrase is “follow the water.” When astronauts set down on the Red Planet in the next decade, they will need access to water to meet their basic needs. Following the water is also crucial to our ongoing exploration of Mars and learning more about its past. While all of the water on the Martian surface exists as ice today (the majority locked away in the polar ice caps), it is now known that rivers, lakes, and an ocean covered much of the planet billions of years ago.

Determining where this water went is essential to learning how Mars underwent its historic transformation to become the dry and cold place it is today. Close to twenty years ago, the ESA’s Mars Express orbiter made a huge discovery when it detected what appeared to be a massive deposit of water ice beneath the southern polar region. However, recent findings by a team of researchers from Cornell University indicate that the radar reflections from the South Pole Layered Deposit (SPLD) may be the result of geological layering.

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Want to Live on Mars? Here's Where the Water is

Mineral map of Mars showing the presence of patches that formed in the presence of water. Credit: ESA

When crewed missions begin to travel to Mars for the first time, they will need to be as self-sufficient as possible. Even when Mars and Earth are at the closest points in their orbits to each other every 26 months (known as “Opposition“), it can take six to nine months for a spacecraft to travel there. This makes resupply missions painfully impractical and means astronauts must pack plenty of supplies for the journey. They will also need to grow some of their food and leverage local resources to meet their needs, a process known as In-Situ Resource Utilization (ISRU).

In particular, astronauts will need to know where to find water on the Red Planet, which is no small challenge. Luckily, the European Space Agency (ESA) has created a mineral map showing the locations of aqueous minerals (rocks that have been chemically altered by water). This map was created by the Mars Orbital Catalog of Aqueous Alteration Signatures (MOCAAS) project and took over ten years to complete. When it comes time to select landing sites for crewed missions to Mars (in the next decade and beyond), maps like this will come in mighty handy!

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The Deepest Known Canyon in the Solar System, Seen From Space

valles marineris canyon

Solar system worlds beyond Earth have amazing surface features. Thanks to planetary science missions, we see images of canyons, craters, and cliffs across a variety of worlds. Someday, those places will give mountain climbers and hikers new challenges. In particular, Mars will be a favored destination. Future hikers and mountain climbers will be spoiled for choice, even if they must wear space suits to get their thrill on.

For example, there’s the Valles Marineris canyon region. It’s the largest known such feature in the solar system, many times larger than the Grand Canyon here on Earth. The European Space Agency’s Mars Express orbiter just returned breathtaking images of this rift canyon.

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