Photos: The best moments on Mars This artist's illustration shows the ExoMars Trace Gas Orbiter as it orbits Mars. The orbiter detected a layer of glowing green oxygen in Mars' atmosphere. Hide Caption 1 of 30

Photos: The best moments on Mars NASA's Curiosity Mars rover took a selfie shortly before completing its steepest climb yet on Mars up the Greenheugh Pediment, which tilted the rover 31 degrees. Hide Caption 2 of 30

Photos: The best moments on Mars NASA's Curiosity rover captured its highest-resolution panorama, including more than a thousand images and 1.8 billion pixels, of the Martian surface between November 24 and December 1, 2019. Hide Caption 3 of 30

Photos: The best moments on Mars The cloud in the center of the image is actually a dust tower that occurred in 2010 and was captured by the Mars Reconnaissance Orbiter. The blue and white clouds are water vapor. Hide Caption 4 of 30

Photos: The best moments on Mars This perspective of Mars' Valles Marineris hemisphere from July 9, 2013, is actually a mosaic comprising 102 Viking Orbiter images. At the center is the Valles Marineris canyon system, over 2,000 kilometers long and up to 8 kilometers deep. Hide Caption 5 of 30

Photos: The best moments on Mars NASA's Curiosity rover took this selfie on October 11, 2019, in the "Glen Etive" region. Hide Caption 6 of 30

Photos: The best moments on Mars The InSight lander was imaged from above by the Mars Reconnaissance Orbiter. Hide Caption 7 of 30

Photos: The best moments on Mars Is that cookies and cream on Mars? No, it's just polar dunes dusted with ice and sand. Hide Caption 8 of 30

Photos: The best moments on Mars The European Space Agency's Mars Express mission captured this image of the Korolev crater, more than 50 miles across and filled with water ice, near the north pole. Hide Caption 9 of 30

Photos: The best moments on Mars A recent photo taken by the Curiosity rover shows its current location, known as "Teal Ridge." The rover has been studying the clay-bearing unit in this region. Hide Caption 10 of 30

Photos: The best moments on Mars Cooled lava helped preserve a footprint of where dunes once moved across a southeastern region on Mars. But it also looks like the "Star Trek" symbol. Hide Caption 11 of 30

Photos: The best moments on Mars NASA's InSight lander used a camera on its robotic arm to capture this sunset on Mars on April 25. Hide Caption 12 of 30

Photos: The best moments on Mars InSight's seismometer recorded a "marsquake" for the first time on April 6, 2019. Hide Caption 13 of 30

Photos: The best moments on Mars A photo of a preserved river channel on Mars, taken by an orbiting satellite, with color overlaid to show different elevations. Blue is low and yellow is high. Hide Caption 14 of 30

Photos: The best moments on Mars This is NASA InSight's first selfie on Mars. It displays the lander's solar panels and deck. On top of the deck are its science instruments, weather sensor booms and UHF antenna. Hide Caption 15 of 30

Photos: The best moments on Mars Rovers can take selfies, too. This self-portrait of the Curiosity Mars rover shows the vehicle at the Quela drilling location in the Murray Buttes area on lower Mount Sharp. Hide Caption 16 of 30

Photos: The best moments on Mars Mars is far from a flat, barren landscape. Nili Patera is a region on Mars in which dunes and ripples are moving rapidly. HiRISE, onboard the Mars Reconnaissance Orbiter, continues to monitor this area every couple of months to see changes over seasonal and annual time scales. Hide Caption 17 of 30

Photos: The best moments on Mars What are blueberries doing on Mars? These small, mineral hematite-rich concretions are near Fram Crater, visited by NASA's Opportunity rover in April 2004. The area shown is 1.2 inches across. The view comes from the microscopic imager on Opportunity's robotic arm, with color information added from the rover's panoramic camera. These minerals suggests that Mars had a watery past. Hide Caption 18 of 30

Photos: The best moments on Mars Mars is known to have planet-encircling dust storms. These 2001 images from NASA's Mars Global Surveyor orbiter show a dramatic change in the planet's appearance when haze raised by dust-storm activity in the south became globally distributed. Hide Caption 19 of 30

Photos: The best moments on Mars Curiosity took images on September 9, 2015, of Mount Sharp, a hematite-rich ridge, a plain full of clay minerals to create a composite and rounded buttes high in sulfate minerals. The changing mineralogy in these layers of Mount Sharp suggests a changing environment in early Mars, though all involve exposure to water billions of years ago. Hide Caption 20 of 30

Photos: The best moments on Mars HiRISE captured layered deposits and a bright ice cap at the Martian north pole. Hide Caption 21 of 30

Photos: The best moments on Mars This image, combining data from two instruments aboard NASA's Mars Global Surveyor, depicts an orbital view of the north polar region of Mars. The ice-rich polar cap is 621 miles across, and the dark bands in are deep troughs. To the right of center, a large canyon, Chasma Boreale, almost bisects the ice cap. Chasma Boreale is about the length of the United States' famous Grand Canyon and up to 1.2 miles deep. Hide Caption 22 of 30

Photos: The best moments on Mars Although Mars isn't geologically active like Earth, surface features have been heavily shaped by wind. Wind-carved features such as these, called yardangs, are common on the Red Planet. On the sand, the wind forms ripples and small dunes. In Mars' thin atmosphere, light is not scattered much, so the shadows cast by the yardangs are sharp and dark. Hide Caption 23 of 30

Photos: The best moments on Mars From its perch high on a ridge, Opportunity recorded this image of a Martian dust devil twisting through the valley below. The view looks back at the rover's tracks leading up the north-facing slope of Knudsen Ridge, which forms part of the southern edge of Marathon Valley. Hide Caption 24 of 30

Photos: The best moments on Mars HiRISE took this image of a kilometer-size crater in the southern hemisphere of Mars in June 2014. The crater shows frost on all its south-facing slopes in late winter as Mars is heading into spring. Hide Caption 25 of 30

Photos: The best moments on Mars The Mars Reconnaissance Orbiter used its HiRISE camera to obtain this view of an area with unusual texture on the southern floor of Gale Crater. Hide Caption 26 of 30

Photos: The best moments on Mars A dramatic, fresh impact crater dominates this image taken by the HiRISE camera on November 19, 2013. The crater spans approximately 100 feet and is surrounded by a large, rayed blast zone. Because the terrain where the crater formed is dusty, the fresh crater appears blue in the enhanced color of the image, due to removal of the reddish dust in that area. Hide Caption 27 of 30

Photos: The best moments on Mars Opportunity used its panoramic camera to record this eastward horizon view on October 31, 2010. A portion of Endeavour Crater's eastern rim, nearly 19 miles in the distance, is visible over the Meridiani Planum. Hide Caption 28 of 30

Photos: The best moments on Mars In this artist's concept of NASA's InSight lander on Mars, layers of the planet's subsurface can be seen below and dust devils can be seen in the background. Hide Caption 29 of 30