Its tests and calibrations complete, NASA's Curiosity rover will soon switch to a long-distance mode to reach its main objective — a towering mound of layered sediments — several months from now.

Curiosity artwork

An artist's concept of NASA's Curiosity rover, a mobile robotic laboratory for investigating Mars' past or present ability to sustain microbial life.


Have you ever dashed off to the grocery store, planning to just grab some milk and eggs, and then you get sidetracked by all the tempting fresh fruit and bakery goodies?

That's basically the situation mission scientists for NASA's Mars Science Laboratory (MSL) find themselves in. It's been 10 months since Curiosity touched down inside Gale crater. The rover's ultimate destination is Aeolis Mons (widely known as "Mount Sharp"), a massive mound that rises 3 miles (5 km) high from the crater's broad floor. This stack of layered sediments likely holds the key to why, when, and how Mars morphed from a clement world gurgling with liquid water in its youth to the stark, frigid, and inhospitable place it is today.

But Curiosity isn't there yet — and likely won't arrive until next year. For the past six months, the rover has been poking around "Glenelg," an area no bigger than a football field with many intriguing geologic outcrops. Since Curiosity is more capable — and more complicated — than any previous interplanetary lander, its handlers have been executing a carefully paced sequence of operations to test all the instruments and mechanisms thoroughly.

Last February ground controllers commanded the craft to drill into an exposure of soft mudstone nicknamed "John Klein." A month later, after instruments had analyzed finely powdered samples of the tailings, scientists reported that this rock contains abundant smectite, a group of clay-like minerals that forms in the presence of water. Also, the presence of calcium sulfates imply that the water probably had a relatively neutral pH and was not strongly salty. It was all good news on the habitability checklist.

On May 19, 2013, Curiosity cut a hole 0.6 inch (1.6 cm) hole into an outcrop called "Cumberland" then used its Chemistry and Camera (ChemCam) instrument to analyze the gray-colored tailings. The small pits were created by firing the ChemCam's powerful infrared laser, which created momentary flashes of white-hot vapor. The instrument's optics then analyzed that light for the spectral fingerprint of specific elements.


Last month Curiosity drilled into a second outcrop, called "Cumberland", then fired its ChemCam laser several times to analyze the powdered tailings. Everything went smoothly, though the analysis of the elements and minerals those contain is ongoing.

But no further drilling is planned before Curiosity starts rolling in earnest. In a few weeks engineers will shift gears to a distance-driving mode that covers more ground and involves fewer sightseeing stops, since the big mound's lower slopes lie about 5 miles (8 km) to the southwest.

The roving geology laboratory would have wrapped up its work in Glenelg sooner, but there were two delays. Earlier this year an electronic glitch halted science activities for about a month, and then communications were suspended for a few weeks when Mars passed very near the Sun as seen from Earth.

Path from Glenelg to Mount Sharp

NASA's Mars rover Curiosity has to travel roughly 5 miles (8 km) to get from the Glenelg region, where it spent the first half of 2013, to the lower slopes of Mount Sharp (Aeolis Mons) to the southwest. The rover's path will likely be within the swath outlined in red. click on the image for a larger view.

NASA / JPL / MSSS / Univ. of Arizona

"The trip to the Glenelg region has been well worth it," says Joy Crisp, MSL's deputy project scientist at the Jet Propulsion Laboratory. "The science team is very pleased with the results that we've gotten."

"We don't know when we'll get to Mount Sharp," comments project manager Jim Erickson in a NASA press release issued Wednesday. "This truly is a mission of exploration." He speculates that it'll take at least 10 months to a year — and that assumes no sightseeing along the way. Yet even now the mission's scientists and engineers are compiling a list of choice spots that they'll have the rover check out in the months ahead.

Landing on Mars isn't easy. Glimpse back into recent history with our free ebook, Mars Landings, Past & Present, and find out why the Curiosity landing was so special.


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Keith Williams

June 7, 2013 at 6:01 pm

Are we there yet???

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John Sheff

June 10, 2013 at 7:50 am

It's not just the drilling. It seems that, for weeks, all we were seeing was Curiosity taking cute self-portraits of itself from different angles. It's great to finally get to Mars, but how many "here's-me-at-the-Grand-Canyon" pictures do we need before we get down to business? After all, this is nomimally a mission designed to last two Earth years; we've spent almost half that time checking out our instruments at Glenelg, and Mt. Sharp is a long way off. Let's get going!

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Bruce Mayfield

June 11, 2013 at 6:25 pm

Good points John. After Kepler’s recent breakdown almost immediately after it’s “warranty expired” it makes me wonder about Curiosity’s longevity too. Sure, the rovers Sprit and Opportunity far outlived their primary missions, but since the power supply for Curiosity is nuclear rather than solar it might not be safe to assume that Curiosity will be the Energizer Bunny of the solar system. How much reserve power is Curiosity’s nuke powered generator expected to have? The way to the base of Mt Sharp is flat to slightly downhill, but once there the going will get tougher when the mountain climbing starts. The average person can easily walk 5 miles in less than a day, but Curiosity needs ten months??? JPL dudes, lets get truckin’ please.

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Star Gazer

June 15, 2013 at 8:09 am

Bruce, these spacecraft are only designed with enough redundancy to perform their primary mission. Anything beyond that is bonus. To consider Kepler's recent breakdown to be some kind of a mission failure is simply incorrect.

Curiosity's nuclear RTG is one of the least likely things to limit Curiosity's extended mission. It has no moving parts and is extremely reliable. It will have enough power to run Curiosity for more than 10 years.

Moving parts are the most likely things to fail. Kepler's dead reaction wheels and Spirit's failed drive wheel being typical examples. Moving parts in Curiosity's lab instruments, the arm/hand/drill mechanism, and the wheel's drive and steering mechanism are things that are likely to fail first over time.

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June 15, 2013 at 4:17 pm

Thanks for that Star Gazer, although I find your comment to be only partially reassuring. It’s fine to hear that Curiosity’s power system was built for the long haul, but when you put your comment that “these spacecraft are only designed with enough redundancy to perform their primary mission” against John Sheff’s comment that “this is nominally a mission designed to last two Earth years” you can see why people can get a bit concerned. I agree that the Kepler mission has been a big success, but that doesn’t change the fact that two of its reaction wheels have failed much sooner than everyone would have wished. IMO Kepler could have found even more planets in longer orbits if only it had been more durable. All we are saying is that it will be shame if after slow crawling in fits and starts to the base of Mt Sharp Curiosity’s moving parts start failing before its main target can be investigated.

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