There used to be more water than anyone realized on Mars, data from the Mars Reconnaissance Orbiter seems to show. Mars' southern highlands have considerable amounts of phyllosilicates, a type of hydrated minerals formed by extensive water exposure. However, no one knew if there were similar minerals on the northern third of the planet, because it is covered by lava plains up to a mile deep three billion years ago. Researchers have wondered if below that layer of lava there might be hydrated minerals, indicated that eons ago liquid water flowed over the surface there as well.

A team of planetary scientists has used radar and a high-resolution camera to reveal the subsurface geology of Mars' northern ice cap. The findings – based on data from SHARAD (the surface-penatrating radar) and HiRISE (the high-resolution camera) on the Mars Reconnaissance Orbiter – were published May 27 in two papers in the journal Nature. The group studying a canyon feature called Chasma Boreale included Shane Byrne from University of Arizona's Lunar and Planetary Laboratory. Jack Holt and Isaac Smith of The University of Texas at Austin's Institute for Geophysics are the papers' lead authors. "The ice sheet on Mars' northern polar region is about the size and thickness of the Greenland ice sheet," said Byrne. "Just like Greenland, the layers of ice on Mars preserve a climate record that reaches back probably a few million years. Studying this ice sheet and its internal layers tells us about Martian climate and how it has varied in the past."

This stunning picture is the first image of Earth ever taken from another planet that shows our home as a planetary disc, with the Moon in the distance. Captured by Nasa's Mars Reconnaissance Orbiter as the spacecraft orbited the Red Planet, both the Earth and the Moon appear as crescents, engulfed in the vast darkness of space. Our planet is captured in a 'half-Earth' phase, while the image also shows the Earth-facing hemisphere of the Moon. Because the Earth and the Moon are closer to the Sun than Mars, they exhibit phases, just as the Moon, Venus, and Mercury do when viewed from Earth.

This image shows the Mars Exploration Rover Opportunity perched on the edge of Concepción Crater in Meridiani Planum, Mars. This image was taken by HiRISE on February 13, 2010, on sol 2153 of Opportunity’s mission on Mars. If you look closely, you can see rover tracks in the ripples to the north and northwest of the rover! Wow! See below for a wonderful colorized close-up version by Stu Atkinson that shows the tracks very clearly. Scientists use these high-resolution images (about 25 cm/pixel) to help navigate the rover. In addition, rover exploration of areas covered by such high-resolution images provides “ground truth” for the orbital data. Oppy has moved along from Concepcion and is now heading towards a set of twin craters. You can check out Stu's blog Road to Endeavour to see what Opportunity is seeing these days. One milestone (meterstone?) Oppy recently reached was hitting 20 km on her odometer and she seems to continue to be in great operating condition. Go Opportunity!

NASA's Mars Reconnaissance Orbiter (MRO) may be the baby of the fleet of spacecraft currently studying the red planet. But the probe has been nothing short of prolific with its Martian observations and recently surpassed more than 100 terabits of data. That number, announced by NASA recently, doesn't mean much to most of us, so SPACE.com has calculated what 100 terabits are in various more everyday measures. Altogether, 100 terabits is 100 trillion bits of information and would take up 17,000 700MB CDs. That would be about 4 million songs, with each lasting about three minute - quite the album collection.

A dramatic picture of an avalanche of Mars has been captured by a powerful camera from orbit. The collapse happened on a towering cliff face in the red planet's far northern arctic region. Scientists believe it happened when the area began to thaw in local spring. Rock, ice and dust were sent plummeting 2,300 ft causing a cloud of fine debris to billow to a distance of 625 ft.

It might look like an oddly circular iceberg in the Antarctic Ocean. But this is actually a crater turned inside-out by time in the Arabia Terra region of Mars. Scientists think such inverted craters form when an impact basin fills with sediment and the material around that sediment gets eroded away. NASA released the false-color, high-resolution picture March 3, 2010, to commemorate a milestone for the Mars Reconnaissance Orbiter: the collection of a hundred trillion bits of data on the red planet. The camera that snapped this shot on January 29, known as HiRISE, is one of six instruments aboard the Mars-orbiting craft.

NASA's newest Mars orbiter, completing its fourth year at the Red Planet next week, has just passed a data-volume milestone unimaginable a generation ago and still difficult to fathom: 100 terabits. That 100 trillion bits of information is more data than in 35 hours of uncompressed high-definition video. It's also more than three times the amount of data from all other deep-space missions combined — not just the ones to Mars, but every mission that has flown past the orbit of Earth's moon. "What is most impressive about all these data is not the sheer quantity, but the quality of what they tell us about our neighbor planet," said Mars Reconnaissance Orbiter Project Scientist Rich Zurek, of NASA's Jet Propulsion Laboratory. "The data from the orbiter's six instruments have given us a much deeper understanding of the diversity of environments on Mars today and how they have changed over time." The spacecraft entered orbit around Mars on March 10, 2006, following an August 12, 2005, launch from Florida. It completed its primary science phase in 2008 and continues investigations of Mars' surface, subsurface and atmosphere.

Vast glaciers of ice are common on Mars, but you have to dig below the surface to find them, new radar views from a NASA spacecraft show. These hidden deposits of buried Martian ice were first confirmed two years ago, but recent scans of the red planet by NASA's Mars Reconnaissance Orbiter are revealing new clues about how the ice may have gotten there. Scientists think the Mars glaciers may have been left as remnants when regional ice sheets retreated. "The hypothesis is the whole area was covered with an ice sheet during a different climate period, and when the climate dried out, these deposits remained only where they had been covered by a layer of debris protecting the ice from the atmosphere," said Jeffrey Plaut of NASA's Jet Propulsion Laboratory in Pasadena, Calif. The ice extends for hundreds of miles, or kilometers, in a mid-latitude region of Mars called Deuteronilus Mensae.

NASA scientists say they've identified thick masses of buried ice in the middle latitudes of Mars and radar mapping suggests the ice is commonplace. The radar images were provided by the space agency's Mars Reconnaissance Orbiter, which is charting the hidden glaciers and ice-filled valleys that were first confirmed by radar two years ago. NASA said the subsurface ice deposits extend for hundreds of miles in a region about halfway from the equator to the Martian north pole.

A space-loving animator has created stunning flyovers of Mars from data captured by NASA’s HiRISE imager, which is mounted on the Mars Reconnaissance Orbiter satellite. HiRISE creates detailed digital-elevation models. Crunch that data, add perspective and some cinematic effects, and you have the movies that Doug Ellison, founder of UnmannedSpaceflight.com, posted to YouTube this morning.

NASA’s Mars Reconnaissance Orbiter has captured more than 13,000 images of the red planet’s surface. And now, the space agency wants your input on what images to acquire next. The High Resolution Imaging Science Experiment (HiRISE) camera is currently the most powerful camera on any NASA spacecraft. The images it has collected are truly amazing. They highlight how similar the Martian landscape is to Earth in some ways, as well as how otherworldly other parts of Mars can seem. We’ve collected just a few of the oddest and most beautiful shots. If they inspire you to want to pick the next strange location for HiRISE to focus on, NASA has created a website where you can scan the planet’s surface and make suggestions.

As with most things in life, NASA missions tend to gain the most attention when they either succeed fantastically or fail utterly. When Apollo 11 touched down on the lunar surface in 1969, the New York Times ran with the headline "MEN WALK ON MOON." And when NASA's Orbiting Carbon Observatory took a nosedive into the Indian Ocean in 2009, newspaper editors and bloggers alike were quick to break out the "FAIL" headlines.

NASA's most powerful Mars orbiter has bounced back from some hard luck around the red planet this year, and scientists are eager to resume the orbiter's detailed observations of Mars in the new year. After a series of glitches that began in February, mission managers put the Mars Reconnaissance Orbiter (MRO) into a protective "safe mode" in August. The spacecraft was resurrected earlier this month and resumed its science operations last week, much to the delight of Mars scientists, who have waited patiently for the orbiter to return to duty. "It's good to have the instruments back on," said MRO mission manager Dan Johnston of NASA's Jet Propulsion Laboratory (JPL), Pasadena, Calif. "This has been a long stand-down. Now we're ready to resume our science and relay mission."

This impact crater is only about 5.5 meters (18 feet) across - tiny compared to the giant basins that scar most planetary bodies. This type of bowl-shaped crater is called a simple crater. It's "simple" compared to larger craters that have terraces, central peaks and rings, and other, more complex, shapes. Why should we care about such a small, plain crater? One reason is that it's extremely young. The large craters we see on Mars are millions to several billion years old, but this crater formed between January 2006 and May 2008. That means it was only a few months to a few years old when HiRISE observed it. We know this because we have been studying Mars with multiple missions over a long time period, and we can compare images of the same area and detect changes. In this case, the Context camera on the Mars Reconnaissance Orbiter took an image that had a dark spot in it.