Mars Rover Curiosity Drops Into Safe Mode

For the first time since 2013, NASA's rover has switched itself into a low-power state as a precaution, but it is still communicating with Earth while engineers work out what happened.

While the Juno spacecraft grabbed all the headlines as it approached Jupiter and the US celebrated the July 4 weekend, another NASA mission wasn't faring so well.

On July 2, Mars rover Curiosity ceased science operations on the slopes of Mount Sharp after a fail safe was tripped, forcing the nuclear-powered robot into a low-power "safe mode."

RELATED: Curiosity Science Suspended After Electrical Glitch

According to a NASA Jet Propulsion Laboratory report, preliminary information communicated by Curiosity suggests an "unexpected mismatch between camera software and data-processing software in the main computer" may have been the culprit and the rover's automated systems took over, preventing any permanent damage from being caused.

Interestingly, Curiosity has gone for a long period without experiencing an unexpected safe mode on the Martian surface. In 2013, the rover experience three separate safe mode events, but none since. It did, however, experience an electrical short in 2015 that forced a pause in science activities.

WATCH VIDEO: A New Clue to Finding Life On Mars

Safe modes are built into all complex space missions that will be automatically triggered should an unexpected systems error arise. Often, safe modes are triggered when a surge in power is detected or an erroneous command is triggered after a cosmic ray impact on internal electronics. In case this is indicative of a bigger fault, a safe mode will be triggered to prevent further damage from occurring while ground controllers can remotely work through the problem.

RELATED: Curiosity Takes a Selfie on Mars

Roving companion Opportunity has suffered many safe modes in its 12 years roving Mars, especially now its on board memory is literally wearing out, causing system instabilities and bouts of "amnesia". Built-in fail safes in Opportunity's software have allowed mission engineers to extend the rover's lifespan well beyond its primary mission of only 3 months.

Though obviously a concern, Curiosity is doing exactly what it is designed to do and it is still communicating with Earth while mission engineers get it back to carrying out ground-breaking science in the middle of Gale Crater.

GALLERY: Curiosity's Epic First Year on a Mars Mountain

Nearly one (Earth) year ago, NASA's Curiosity rover arrived at Mount Sharp, the key science destination of its mission. The rover has now spent three Earth years on the Red Planet, looking at rocks and environment to try to piece together the ancient past of Mars. Was it habitable for life? If so, did the life disappear? Why did the conditions change? These are all questions investigators are trying to learn the answers to. In this brief rundown of the science being done on Mount Sharp (officially known as Aeolis Mons), we've picked out some of the most intriguing and, frankly, beautiful photos of Curiosity's mountain.

This is one of the latest ones from Curiosity, showing it perched at the Marias Pass just after doing some drilling. While the selfies are used as a public relations tool, NASA also uses these pictures to monitor the condition of the rover in the harsh Martian environment. After extensive practice taking pictures of the rover, Curiosity's "selfies" are getting pretty amazing.

Yep, that's a rock -- there are a lot of those on Mars. But look more closely at each one, and they reveal surprises. This particular rock is

embedded with silica

, a silicon-oxygen rock-forming compound that often shows up on Earth as quartz. It's an unusual find for Mars, and the team said it is going to take a closer look to see if it could preserve organic materials. Organics are considered building blocks of life, but not necessarily signs of life itself.

MORE: NASA's Curiosity Rover Eyes Weird Rock on Mars

Curiosity has a laser on board (called the Chemistry and Camera or ChemCam instrument) that shoots at rocks to figure out what they are made of. But for months, the auto-focuser malfunctioned and required multiple laser shots to be sent, slowing down the science. This image shows the result after a successful software update that takes several images and figures out how to target the focuser from there.

In 28 pictures stitched together, Curiosity uncovered an extensive network of mineral veins at a site investigators dubbed "Garden City." These veins are created when a liquid cuts through cracks in a rock and leaves minerals behind. At the time this picture was taken, NASA was trying to figure out what the fluids were made of, and how the rock changed after the fluids touched it. It's all part of better understanding the ancient wet past on Mars and prospects for life.

MORE: Curiosity Has Hit a Martian Mineral Jackpot

Sometimes you can't predict what will happen when you do science. In this case, Curiosity's drill did a test to see if this "Mojave" rock could be suitable to collect a sample... and the rock shattered. While it wasn't a total surprise that the rock broke, what made this test interesting was it created a few rock chips. This gave Curiosity an opportunity to look at what a new rock looks like before it gets all weathered by Martian wind and elements.

MORE: Robot Smash! Curiosity Shatters Mars Rock Slab

In December, couple of building blocks of life came to light: Curiosity saw a 10-fold spike and fall in methane around this time, and detected carbon-bearing organic molecules on Mars. While neither of these are necessarily signs of life, they point to conditions that could have been friendly for life at some point. Also, Curiosity got to flex its drill at the "Cumberland" rock target, which was a good thing as a NASA senior review said the drill wasn't being used enough (making it hard to justify the cost and complication).

MORE: Mars Mission Will Drill Deep for Inside Information

The very first hole

that Curiosity created in Mount Sharp revealed something exciting: the mineral it found was the same as one seen from orbit in the same region. Specifically, the rover found evidence of hematite, an iron oxide mineral that can precipitate out of water. Hematite was noted as a mineral of interest when the Curiosity landing site was being selected in 2010.