NASA / JPL-Caltech / MSSS

The laser-equipped ChemCam instrument on NASA's Curiosity rover was used to check the composition of gray tailings from the hole drilled in a rock called Cumberland. This image, taken on May 21, shows a row of small pits created by firing the ChemCam's laser at the tailings. The pits are near the drill hole, which has a diameter of about 0.6 inch (1.6 centimeters).

After spending the past four months drilling holes in rocks on Mars, the team controlling NASA's Curiosity rover has set a course for the $2.5 billion mission's ultimate destination, a 3-mile-high (5-kilometer-high) mountain in the middle of the crater where Curiosity landed 10 months ago.

"We're going to hit the road and embark on a really new phase of the mission," Joy Crisp, the mission's deputy project scientist at NASA's Jet Propulsion Laboratory, said Wednesday during a teleconference with journalists.

Curiosity's managers selected Gale Crater specifically because of the mountain, known as Aeolis Mons or Mount Sharp. Its layers of rock are thought to preserve billions of years' worth of geological history. "It's like looking at the layers in Grand Canyon," Crisp explained.

A close examination of those layers could yield evidence of the chemical constituents of life. That's the top goal for the Mars Science Laboratory mission, which is slated to last two Earth years.

Valuable detour
The rover's current workplace, known as Glenelg, was actually a detour from the mountain trek, selected because orbital imagery suggested that it was an area of geological interest. That suggestion turned out to be right on: When Curiosity analyzed the powder that was drilled out of a rock nicknamed John Klein, researchers found that the material pointed to an ancient environment that would have been favorable for microbial life.

More recently, Curiosity spent three weeks to drill out samples and analyze the powder from a different rock nearby, nicknamed Cumberland. The rover's sample-handling device is hanging onto some of that powder in case scientists want to do further analysis.

The Curiosity rover drills a hole into Cumberland. Credit: NASA / JPL-Caltech / Ken Kremer / Marco Di Lorenzo

Over the next several weeks, the 1-ton mobile lab will take on three more tasks at Glenelg. First, it will study a strange rocky outcrop called Point Lake, which has the texture of Swiss cheese. The rock might be composed of volcanic lava, or it might be sedimentary in nature. "It's a nice mystery," Crisp said.

Curiosity will also take a close look at a layered outcrop called Shaler, which might have been a riverbed in ancient times. Along the way, it will use an instrument known as DAN, or Dynamic Albedo of Neutrons, to check for the signatures of ancient water at a boundary between areas of mudstone and sandstone.

In the meantime, mission managers will pore through orbital imagery for stopping points of scientific interest on the 5-mile (8-kilometer) route from Glenelg to Mount Sharp. So far, the rover has put just 2,405 feet (733 meters) on its odometer, so the trek to Mount Sharp will be monumental. "Somewhere between 10 months and a year might be something like a fast pace" for the trip, said Jim Erickson, the mission's project manager.

Crisp said she and the team's other scientists were anxious to get started. "It's like being on a vacation, and you spend a lot of time in a little area, and you've done a lot there — and you want a change of pace," she said.

That 'Mars rat'
During the trip, Curiosity will no doubt pass by roadside attractions like the "Mars rat" that made such a splash over the past week. Crisp said the ratlike shape was created through wind erosion, mechanical abrasion and chemical weathering.

"In all honesty, I think that the scientists get so much more engrossed in the interesting textures and trying to figure out how the rocks form, that we're amused when people point out that this shape happens to look like something else," she said. "But we don't spend a lot of time thinking about why that is."

Crisp indicated that she didn't mind the hubbub over strange shapes. "It's kind of fun, in a way ... in that it will attract a lot of the public to look at the images, and learn a little bit about Mars," she said.

More about Mars:

• 'Mars rat' taking Internet by storm
• 'Penis on Mars' sparks fresh titters
• Cosmic Log archive on Mars

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the NBC News Science Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with NBCNews.com's stories about science and space,sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

NASA / JPL-Caltech

A Martian view from one of Curiosity's hazard avoidance cameras, transmitted back to Earth on Thursday, shows the shadow of the instrument turret on the rover's robotic arm.

NASA's Curiosity rover is back in business after a weeks-long communication gap caused by solar interference. The proof comes in the form of pictures transmitted back to Earth on Thursday from the 1-ton machine's vantage point at Yellowknife Bay on Mars.

"Can you hear me now? Conjunction is over. I have a clear view of Earth & am back to work!" the rover tweeted (with a little help from her entourage at NASA's Jet Propulsion Laboratory).

Dozens of raw images are on display on NASA's Mars Curiosity website, featuring rocky terrain in the foreground and the 3-mile-high (5-kilometer-high) peak known as Mount Sharp or Aeolis Mons in the background. Other Mars probes, including the Opportunity rover, Mars Odyssey and Mars Reconnaissance Orbiter, are back at work as well.

NASA's Red Planet probes were on hiatus for most of April due to an unfavorable alignment of Mars, Earth and the sun. During solar conjunction, the sun gets in the way of the communication lines between the two planets, and mission controllers generally put science operations on hold. Such conjunctions occur every 26 months. Opportunity has gone through several communication breaks during its nine years on Mars, but this is the first one to occur since Curiosity landed last August.

The spacecraft weren't completely idle during the break: Curiosity conducted in-place investigations and sent back limited transmissions via X-band radio to let controllers at NASA's Jet Propulsion Laboratory know that it was doing OK. Opportunity autonomously flipped its computer into safe mode during the break, apparently due to a glitch involving a routine camera check. A fresh set of software commands fixed the glitch, and on Wednesday controllers reported that Opportunity was back in working order.

Curiosity is due for its own software upgrade, and then the rover is scheduled to drill out a second sample of ground-up rock for analysis. The first sample, analyzed in March, suggested that the Yellowknife Bay environment was potentially habitable billions of years ago. Scientists want to use the follow-up sample to confirm what they saw in previous chemical analyses.

After Curiosity finishes up its work in Yellowknife Bay and its surroundings in the Glenelg area of Gale Crater, controllers plan to point the rover toward Mount Sharp, 6 miles (10 kilometers) away. The science team suspects that the mountain's many layers of rock will hold further evidence of ancient organic chemistry.

More about Mars:

• Cosmic Log archive on Curiosity
• Old phallic picture on Mars sparks new titters
• NASA lets poets send haiku to Red Planet

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

NASA

An artist's conception shows how Mars' atmosphere might have been stripped away by a stream of electrically charged particles from the sun.

Scientists say new readings from NASA's Curiosity rover have confirmed how Mars lost its once-thick atmosphere.

The measurements from Curiosity's Sample Analysis at Mars instrument, or SAM, provide fresh support for the view that a high-velocity stream of electrically charged particles from the sun has been stripping off Mars' atmosphere from the top. Mars is more vulnerable to that kind of atmospheric loss than Earth because it doesn't have a global magnetic field to serve as a shield against the solar wind.

Today, Mars' atmosphere is only 1 percent as dense as of Earth's on the surface, and consists mostly of carbon dioxide. The atmosphere is so thin that warmed-up ice turns directly into water vapor without passing through a liquid state. But scientists have seen geological evidence that water flowed abundantly over parts of the Red Planet billions of years ago. That implies that the atmospheric pressure was once much more Earthlike. So where did the missing air go?

Curiosity's science team presented the verdict from SAM on Monday during the European Geosciences Union's General Assembly in Vienna. The key clue is a precise measurement of various isotopes of argon, an inert gas that exists in trace amounts in the Martian atmosphere. Different isotopes of the same element have different atomic weights, and SAM was able to distinguish between those weights with unprecedented precision.

SAM's science team determined that the Martian atmosphere contains more of a lighter argon isotope (argon-36) than a heavier isotope (argon-38) — about four times as much. However, that ratio is lower than the solar system's original ratio of 5.5-to-1, as estimated from argon-isotope measurements of the sun and Jupiter. That would favor a process that stripped away Mars' ancient atmosphere from the top down, with more of the lighter isotopes of gases blown away.

Scientists have long suspected that the solar wind was the culprit for atmospheric loss, based on what happened to other isotopes in Martian air. But the argon measurements are more conclusive, because argon doesn't react with other elements. Thus, Curiosity's team could exclude a scenario in which constituents of the Martian atmosphere were removed by reacting with surface chemicals.

"We found arguably the clearest and most robust signature of atmospheric loss on Mars," Sushil Atreya, a SAM co-investigator at the University of Michigan at Ann Arbor, said in a NASA news release.

Slideshow: Curiosity's space odyssey to Mars

Trace the Curiosity rover's journey to Mars and see the pictures that the six-wheeled robot has sent back from the Red Planet.

Launch slideshow

More about Mars:

• Parachute flaps in the Martian breeze
• Probe to study Red Planet's atmosphere
• Rover finds organics, but are they from Mars?

For more about the SAM team's findings, check out this report from the BBC's Jonathan Amos.

 Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

NASA's Curiosity and Opportunity rovers aren't the only human-made objects that have been on the move on Mars: The Red Planet's winds have set Curiosity's discarded parachute rolling around on the surface, as seen in a series of images captured by the Mars Reconnaissance Orbiter over the course of five months.

The 65-foot-wide (20-meter-wide) parachute and the rover's protective backshell were thrown clear of the rover while it descended to its historic landing in Mars' Gale Crater last August. For a few weeks thereafter, they pretty much stayed where they were. But by the end of November, the orbiter's sharp-eyed HiRISE camera picked up changes in the parachute's shape and position. What's more, the dark marks left on the Martian surface by the backshell's impact started fading away.

The fading of the dark streaks could be explained by the deposition of airborne dust, according to the University of Arizona's Alfred McEwen, who heads the HiRISE science team. The winds that whip through Mars' thin atmosphere are also thought to be responsible for the parachute's changing position.

"This type of motion may kick off dust and keep parachutes on the surface bright, to help explain why the parachute from Viking 1 (landed in 1976) remains detectable," McEwen wrote in Wednesday's image advisory.

If you have red-blue glasses, check out this 3-D view of the parachute and the backshell.

NASA / JPL-Caltech / Univ. of Arizona

A color picture from the HiRISE camera on NASA's Mars Reconnaissance Orbiter shows the Curiosity rover's parachute and backshell spread out on the Martian surface.

Although the parachute may be on the move, Curiosity itself is definitely staying put for the rest of the month: Mars and Earth are on directly opposite sides of the sun, which interferes with radio communication. As a result, NASA will suspend sending commands to the rover starting on Thursday. Opportunity, MRO and the Mars Odyssey orbiter will be out of radio contact for most of April as well. Curiosity and Opportunity will be executing pre-programmed commands to continue their scientific work, and both rovers are expected to be back on the move in May.

More about Mars:

• Curiosity resumes rock analysis after glitch
• How a Martian mountain would look on Earth
• NBC News archive on Mars

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

NASA / JPL-Caltech / Marco Di Lorenzo / Ken Kremer

The Curiosity rover's instrument-laden robotic arm is front and center in this mosaic view captured by the Mars rover's NavCam system and assembled by Marco Di Lorenzo and Ken Kremer. The colorized black-and-white imagery was captured on March 23. Click on the image to see the full panorama.

After a week of down time due to a computer glitch, NASA's Mars Curiosity rover is once again sending back pictures of its rocky Red Planet locale at Yellowknife Bay. In this fresh panorama, the rover looks as if it's sticking its drill-equipped robotic arm right in your face.

"That drill is hungry, looking for something tasty to eat, and 'you' (loaded with water and organics) are it," jokes scientist-writer Ken Kremer, who collaborated with Italian colleague Marco Di Lorenzo to assemble the panorama.

Curiosity's percussive drill played a key role in the science team's most recently reported breakthrough: the finding that powder drilled out of a Martian rock contained the chemical traces of a life-friendly environment that existed on Mars billions of years ago. The team's chemical analysis of the powder indicated that the minerals were probably formed in the presence of drinkable water.

That kind of water no longer exists in liquid form on the Martian surface. The place where Curiosity is currently working may have once been in the vicinity of a riverbed, but it's now a cold and dry wasteland of sand and rock. In the weeks to come, Curiosity's scientists plan to drill into the rock again, looking for confirmatory clues about the potentially habitable environment in the Red Planet's past.

The plan has been held up due to a series of minor setbacks — including a memory failure that may have been due to a cosmic-ray strike, a precautionary stand-down to weather a solar storm, and most recently a computer file glitch that put the rover into safe mode. The Curiosity team has been carefully bringing the rover back to full operation, and this picture is presumably part of the checkout process.

It won't be long before the rover will once more have to reduce its contact with its handlers back on Earth, due to an Earth-Mars-sun conjunction that will interfere with radio signaling. Curiosity's communication gap is expected to last from April 4 to May 1, as detailed in a mission update from NASA's Jet Propulsion Laboratory. During the break, Curiosity is expected to carry on with its experiments, but the transmission of science data and images will have to wait until May. So let's enjoy these fresh images while we can.

For more of Curiosity's raw imagery, check out the galleries on JPL's Mars Science Laboratory website. You'll also find great pictures on UnmannedSpaceflight.com, where Kremer, Di Lorenzo and other image-processing gurus post their work. If you have 3-D glasses, whip 'em out and take a look at Ed Truthan's red-blue view of Curiosity's first drilling site.

Slideshow: Curiosity's space odyssey to Mars

Trace the Curiosity rover's journey to Mars and see the pictures that the six-wheeled robot has sent back from the Red Planet.

Launch slideshow

More about Mars:

• How a Martian mountain would look on Earth
• What's next for the Curiosity rover
• NBC News archive on Mars

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log and the rest of NBCNews.com's science and space coverage, sign up for the Tech & Science newsletter, delivered to your email in-box. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

NASA / JPL-Caltech / MSSS

This mosaic of images from the Mast Camera (Mastcam) on NASA's Mars rover Curiosity shows Mount Sharp, also known as Aeolis Mons, in a white-balanced color adjustment that makes the sky look overly blue but shows the terrain as if under Earthlike lighting. This is just a small segment of a wider panorama assembled from image data collected on Sept. 20, 2012. The sky has been filled out by extrapolating color and brightness information from the portions of the sky that were captured in images of the terrain. A raw-color version of the mosaic shows the scene's colors as they would look in a typical smartphone camera photo taken on Mars. Click on the image to see a larger version from NASA.

If you could pull up a 3-mile-high mountain from Mars and plop it down in California's Mojave Desert, it'd probably look much like this latest color panorama from the Curiosity rover's science team. This little piece from the panorama doesn't do justice to the whole picture: You really should see the whole thing at high resolution to get a sense of just how much Mount Sharp, a.k.a. Aeolis Mons, looms over the scene where NASA's six-wheeled robotic lab has been working.

The most jarring thing about the picture is the blue sky. No, the Martian sky doesn't really look like that. The Red Planet's atmosphere is filled with iron-rich dust that turns everything into shades of butterscotch, burnt orange and brick. To see Mount Sharp as you or your smartphone camera might see it if you were actually there, check out this true-color version of the panorama.

The blue-sky version has been processed to reflect a white-balanced view, as if the picture were taken in an earthly rather than a Martian setting. Why would scientists bother with a phony view of Mars? "White-balancing helps scientists recognize rock materials based on their experience looking at rocks on Earth," NASA's Jet Propulsion Laboratory explains in Friday's photo advisory. It's as if Curiosity was able to get rid of all that red dust in the air and take a clear picture of the mountainside from miles away.

The pictures for this panorama was taken in September, while the rover was en route to its first destination. For the past couple of months, Curiosity has been studying the rocks at a site known as Yellowknife Bay, and it's already turned up some amazing discoveries about Mars' past — including evidence that the area was capable of supporting microbial life billions of years ago.

Within the next couple of months, Curiosity is due to turn around and begin its 6-mile (10-kilometer) trek to the foothills of that big mountain. Pictures like this panorama will help scientists figure out exactly where their nuclear-powered robotic geologist should be going.

Slideshow: Curiosity's space odyssey to Mars

Trace the Curiosity rover's journey to Mars and see the pictures that the six-wheeled robot has sent back from the Red Planet.

Launch slideshow

More about Mars:

• Martian rock reveals life-friendly conditions
• What's next for Mars Curiosity rover
• NBC News archive on Mars

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other science coverage, sign up for the Tech & Science newsletter, delivered to your email in-box. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

NASA / JPL-Caltech / Ken Kremer / Marco Di Lorenzo

This colorized view is part of a panorama produced by Ken Kremer and Marco Di Lorenzo from NASA imagery. The picture shows NASA's Curiosity rover putting its drill to work at Yellowknife Bay on Mars. Click on the picture to see a larger version, and visit KenKremer.com for more from Ken Kremer.

Even as the scientists behind NASA's Curiosity rover mission announced that they found evidence of life-friendly chemistry inside a Martian rock, the $2.5 billion mission's engineers continued their efforts to get the rover back into full operation after a serious computer glitch.

The rover's scientific work in a spot known as Yellowknife Bay has been put on hold while the mission operations team rebuilds the memory for one of Curiosity's two redundant computers, known as the A-side. The A-side computer experienced a memory failure on Feb. 28, forcing controllers to switch over to the B-side backup brain. Since then, the team has been putting the A-side through a series of tests to make sure it's OK.

"We have been able to store new data in many of the memory locations previously affected and believe more runs will demonstrate more memory is available," Jim Erickson, the mission's deputy project manager at NASA's Jet Propulsion Laboratory, said Monday in a status report. A couple of software patches are due to be uploaded and tested this week, and then the team will reassess when to resume full mission operations, including the analysis of additional rock samples.

Engineers still don't know why the A-side failed, although they suspect it may have been due to a cosmic-ray hit. Such hits are thought to have affected Mars Reconnaissance Orbiter in the past. After the computer system returns to full redundant mode, the B-side will continue to operate as Curiosity's main computer while the A-side serves as backup, NASA spokesman Guy Webster told NBC News on Wednesday.

Mars is heading into a solar conjunction in April that will interfere with communications between Curiosity and Mission Control, and science operations will have to be suspended again during that hiatus. That means the rover won't drill out another sample of rock powder from Yellowknife Bay until May.

Scientists say Yellowknife Bay could have been a riverbed or lake bed in ancient times — just the right kind of place for figuring out what Mars was like billions of years ago.

"I have an image now of possibly a lake, a freshwater lake on a Mars with probably a thicker atmosphere, maybe a snow-capped Mount Sharp. Who knows?" said John Grunsfeld, NASA's associate administrator for the science mission directorate.

Curiosity's science team members are so intrigued by what they've been finding that they're willing to go slow with the rover's long-planned trip to Mount Sharp, a 3-mile-high (5-kilometer-high) peak in the middle of Mars' Gale Crater. The layers of rock that make up that mountain, also known as Aeolis Mons, are thought to preserve Mars' geological record over billions of years.

"When we start driving to Mount Sharp, and you see us dragging our feet as we go along there and stop to look at a few things, that's because we'll be trying to figure out how the rocks we're at now, at Yellowknife Bay, relate to Mount Sharp," said Caltech's John Grotzinger, the mission's project scientist.

Slideshow: Curiosity's space odyssey to Mars

Trace the Curiosity rover's journey to Mars and see the pictures that the six-wheeled robot has sent back from the Red Planet.

Launch slideshow

Extra credit: The Mars Curiosity crew is coming in for more accolades. The Mars Science Laboratory Project, which is in charge of building and operating the rover, has been selected to receive the National Air and Space Museum's Trophy for Current Achievement at a ceremony next month. Meanwhile, the folks who manage Mars Curiosity's online persona have won the 2013 South by Southwest Interactive Award for best social media campaign. Congratulations to the "hive mind" behind @MarsCuriosity on Twitter.

More about Mars:

• Organics found, but are they from Mars?
• Radar reveals traces of huge Martian flood
• Cosmic Log archive on Mars

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

Powder drilled out of a rock on Mars contains the best evidence yet that the Red Planet could have supported living microbes billions of years ago, the team behind NASA's Curiosity rover said Tuesday.

"I think this is probably the only definitively habitable environment that we have described and recorded," said David Blake, a scientist at NASA's Ames Research Center who is the principal investigator for Curiosity's CheMin lab.

The findings are in line with what the scientists hoped to find when they sent the 1-ton, six-wheeled laboratory to Mars' Gale Crater. "It wasn't serendipity that got us here. It was the result of planning," Caltech's John Grotzinger, the $2.5 billion mission's project scientist, told reporters at NASA Headquarters in Washington on Tuesday.

Serendipity did, however, play a part in being able to find the evidence so soon, he said. Curiosity's handlers had planned to have the rover head for a 3-mile-high (5-kilometer-high) mountain in the middle of the crater. But when the rover landed, the science team decided to send Curiosity on a detour to a geologically interesting area in the opposite direction, nicknamed Yellowknife Bay. Preliminary readings showed that the area had been a riverbed or lake bed in ancient times.

Last month, the rover finally got a chance to drill into a Martian rock that was named John Klein, after a member of the mission team who died in 2011. Curiosity fed tablespoons of the ground-up gray powder into its two onboard chemical labs: CheMin (Chemistry and Mineralogy) and SAM (Sample Analysis at Mars). The results were announced at Tuesday's news briefing.

Scientists said the powder contained the elemental ingredients of life — including sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon. More significantly, they found that clay minerals made up at least 20 percent of the sample. On Earth, these clays are produced when relatively fresh water reacts with igneous minerals such as olivine. The scientists also found calcium sulfate, which suggested that the water had a neutral or mildly alkaline balance.

Earlier NASA missions had found evidence that salty, acidic water was once present on Mars, but that extreme environment would have been challenging for today's Earth-type organisms. Curiosity's chemical analysis produced a different result: The water that was available during the formation of the rock at Yellowknife Bay, billions of years ago, could have supported the kind of life commonly found on Earth.

"We have found a habitable environment which is so benign and supportive of life that probably if this water was around, and you had been on the planet, you would have been able to drink it," Grotzinger said.

NASA / JPL-Caltech / Ames

A side-by-side comparison shows the X-ray diffraction patterns of two samples collected by Curiosity. The left side shows data from a sample collected from a drift of windblown dust, and the right side shows data from the powder drilled out of the John Klein rock. The John Klein readings show an abundance of phyllosilicate, a class of clay minerals called smectites that form by the action of relatively pure and neutral pH water on minerals.

NASA / JPL-Caltech / Cornell / MSSS

The left image shows Wopmay rock in Endurance Crater, as studied by NASA's Opportunity rover. The right image shows Sheepbed in Yellowknife Bay, as studied by Curiosity. Scientists say both rocks were formed in the presence of water, but the water at Wopnay was highly acidic and salty, while the water at Sheepbed had a more neutral pH and lower salinity.

The scientists said they were surprised to find a mixture of oxidized and non-oxidized chemicals, allowing for the type of chemistry that earthly microbes use to generate the energy they need for survival. This partial oxidation was first hinted at when the drill cuttings were revealed to be gray rather than red.

"The range of chemical ingredients we have identified in the sample is impressive, and it suggests pairings such as sulfates and sulfides that indicate a possible chemical energy source for microorganisms," SAM principal investigator Paul Mahaffy said in a NASA news release.

NASA said another drilled sample would be used to help confirm the chemical findings for several of the trace gases that were analyzed by the SAM instrument.

The current plan calls for Curiosity to conduct experiments in the Yellowknife Bay for weeks or months longer, and then begin a roughly 6-mile (10-kilometer) drive to the big mountain, known as Mount Sharp or Aeolis Mons. Scientists will look for further evidence of ancient organic chemistry hidden in the mountain's many layers of rock.

The primary aim of Curiosity's two-year primary mission is to find evidence of past habitability — in particular, organic carbon compounds that could have played a role in the chemistry of life billions of years ago. Grotzinger said Curiosity's scientists will focus on the systematic search for organic carbon now that they had "the issue of habitability in the bag."

NASA intends to follow up on Curiosity's findings with future Mars missions, including the $500 million MAVEN orbiter (due for launch this year), the $425 million InSight drill-equipped lander (set for 2016 launch) and another Curiosity-like rover that's scheduled to be sent out in 2020. 

Slideshow: Curiosity's space odyssey to Mars

Trace the Curiosity rover's journey to Mars and see the pictures that the six-wheeled robot has sent back from the Red Planet.

Launch slideshow

More about Mars:

• Organics found, but are they from Mars?
• Radar reveals traces of huge Martian flood
• Cosmic Log archive on Mars

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

This story was originally published on Tue Mar 12, 2013 1:48 PM EDT

NASA / JPL-Caltech / MSSS

This image from NASA's Curiosity rover shows the first tablespoon of powdered rock extracted by the rover's drill. The image was taken after the sample was transferred from the drill to the rover's scoop.

The scientists and engineers behind NASA's Curiosity rover say they're thrilled to see the first tablespoon of rock dust drilled from the interior of a rock on Mars — and they're intrigued by the fact that it's gray, not red.

"We're seeing a new coloration for Mars here, and it's exciting for us," Joel Hurowitz, sampling system scientist for the Curiosity mission at NASA's Jet Propulsion Laboratory, told reporters during a teleconference on Wednesday.

Things could get more exciting in the next few days, when Curiosity's sampling system drops dollops of the dust into the rover's onboard chemistry labs, known as CheMin (which stands for Chemistry and Mineralogy) and SAM (Sample Analysis at Mars). The main goal of the $2.5 billion mission is to find organic compounds on Mars, and scientists suspect that the gray interior of rocks could preserve those organics better than the red, highly oxidized surface.

"All things being equal, it's better to have a gray color than a red color," said Caltech's John Grotzinger, the mission's project scientist, "just simply because oxidation ... is something that we know destroys organic compounds."

The rover has spent several weeks at a rock formation known as John Klein in preparation for this first drilling operation, six months into what's expected to be a two-year primary mission. Some scientists and engineers have been working for years in anticipation of Wednesday's first sight of ground-up rock in Curiosity's sampling cup.

"For the sampling team, this is the equivalent of the landing team going crazy after the successful touchdown," said JPL's Scott McCloskey, drill systems engineer for the Curiosity mission.

The sample came from a 2.5-inch-deep hole that Curiosity drilled into the Martian bedrock on Feb. 8. One of McCloskey's colleagues at JPL, sample system chief engineer Louise Jandura, noted that this was the first time a rover has drilled samples out of a rock on another planet. Earlier missions have used grinders to scrape off the top layer of a Martian rock, but none has gone down as deeply as Curiosity did.

"In the five-decade history of the Space Age, this is indeed a rare event," she said.

Grotzinger said getting the samples represented the final milestone in the commissioning process for the rover. Last week marked the "passing of the keys to the rover" from the engineering team to the science team, he noted. "It's a real big turning point for us," Grotzinger said. 

NASA / JPL-Caltech / MSSS

At the center of this image from NASA's Curiosity rover is the hole in a rock called "John Klein" where the rover conducted its first sample drilling on Mars. The drilling took place on Feb. 8. Several preparatory activities with the drill preceded this operation, including a test that produced the shallower hole on the right two days earlier.

NASA / JPL-Caltech / MSSS

This image from October 2012 shows the location of a sieve screen on the Curiosity rover that is used to remove large particles from samples before delivery to science instruments. Scientists say problems that came to light on a test unit on Earth have led them to change their procedures for sifting Martian samples.

Going through glitches
It will take a few more days to start analyzing the ground-up rock: Some of the material in the cup is being used to clear out the plumbing in the rover's sample delivery system. Once scientists back on Earth see imagery confirming that everything is working as expected, they'll give the go-ahead for more of the material to be shaken through a sieve and then deposited into CheMin and SAM for analysis.

A software glitch delayed the sampling operation, McCloskey said, but the team found a work-around that allowed the task to continue with no loss of functionality. "It didn't end up being a significant roadblock to getting this done," he said.

Another concern arose when engineers found that the sieve on one of the test items back on Earth started coming loose after about 60 shaking operations, also known as "thwacks." That was a signal to the rover team that there was "reason to be cautious," said JPL's Daniel Limonadi, lead systems engineer for Curiosity's surface sampling and science system.

The team decided to reduce the shaking time from 60 minutes to 20 minutes at a time, which should be long enough for most samples. If it isn't, the rover will just keep shaking the stuff until the job is done, Limonadi said.

What the rocks may reveal
Hurowitz said the evidence so far suggests that Curiosity is looking at a sedimentary rock formation that was "more likely deposited in water." Veins of whitish material appear to consist of calcium sulfate, which could provide additional clues to the formation's aqueous origins. He said about 25 separate analyses have been conducted with Curiosity's Alpha Particle X-ray Spectrometer, more than 100 images have been recorded by the Mars Hand Lens Imager, and the ChemCam instrument has taken 12,000 laser shots at the rock.

The gray color of the rock dust suggests that the interior of Martian rocks may reflect ancient geological processes that are significantly different from the current weathering process on the Red Planet, Hurowitz told NBC News.

"This is something that the science team is really excited about — the fact that the tailings from our drill operation aren't the typical rusty orange red that we associate with just about everything on Mars," he said. "You can probably bet that when things turn orange, it's because there's a rusting process of some kind going on that oxidizes the iron in the rock. So the fact that these rocks aren't that color may be telling us that these rocks didn't go through that process that usually turns things to rust on Mars. It may preserve some indication of what iron was doing in these samples without the effect of some later oxidative process."

Eventually, Curiosity will be commanded to retrace its route and head for a 3-mile-high (5-kilometer-high) mountain known as Aeolis Mons or Mount Sharp. But Grotzinger emphasized that the mission was "discovery-driven" — and that the rover team was in no hurry to have the rover make its mountain trek.

"We're going to take it one step at a time," Grotzinger said.

More about Mars:

• Curiosity finds organics, but are they from Mars?
• Mars rover driving through dried-up stream bed
• Cosmic Log archive on the Curiosity mission

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

NASA / JPL-Caltech / MSSS

Scientists say that a "Martian flower," seen here in an image from the Curiosity rover's Mars Hand Lens Imager, is a 2-millimeter-wide grain or pebble that's embedded in the surrounding rock. Another, darker-colored mineral grain can be seen above and to the left.

The scientists behind NASA's $2.5 billion Curiosity rover mission on Mars on Tuesday explained the nature of a tiny, gleaming "flower" embedded in Red Planet rock, and revealed where they'll be using the SUV-sized robot's drill for the first time.

Both those developments point to the same happy discovery: The place where the rover is working was almost certainly formed through the action of water — and seems likely to provide new insights into the planet's geological history. "This is something that we've waited patiently for," Caltech geologist John Grotzinger, the mission's project scientist, told journalists during a NASA teleconference.

The "Martian flower" made a splash on the Internet, in part because it looked so different from the surrounding rock in a microscopic-scale picture from Curiosity's Mars Hand Lens Imager, or MAHLI. Few people thought it was actually a flower, though it looked a bit like one. Was it a piece of plastic from the rover itself? An unusual type of mineral?

The Planetary Science Institute's R. Aileen Yingst, deputy principal investigator for the MAHLI team, delivered the expert verdict. It's a relatively large mineral grain, or "a pebble, if you wish," measuring about a tenth of an inch (2 millimeters) wide. "It could be a lot of things, but without some chemical information to back me up, I'd really hesitate to say what it is," she said.

She pointed out that a couple of similar, darker-colored grains could be seen embedded nearby. The important thing is what such rounded grains have to say about the scene's history. "They've been knocked around, they've been busted up. They've been rounded by some process," she said. That suggests that running water helped form the rock, which has been nicknamed Gillespie Lake.

Drill, rover, drill
Five months after its landing, the six-wheeled Curiosity rover is surrounded by plenty of additional evidence that water had a hand in shaping the landscape billions of years ago. That's why Grotzinger and his colleagues have decided to put the rover's heavy-duty drill to work for the first time on a flat spread of rock called "John Klein." The name pays tribute to John W. Klein, a former deputy project manager for the Mars Science Laboratory mission who died in 2011.

"John's leadership skill played a crucial role in making Curiosity a reality," Richard Cook, the mission's project manager, said in a news release.

NASA / JPL-Caltech / MSSS

This image of an outcrop at the "Sheepbed" locality, taken by NASA's Curiosity Mars rover with its right MastCam on Dec. 13, show well-defined veins filled with whitish minerals, interpreted as calcium sulfate. These veins form when water circulates through fractures, depositing minerals along the sides of the fracture, to form a vein. This is Curiosity's first close look at minerals that formed within water that percolated within a subsurface environment.

Cook told reporters that the first drilling operation would probably take place in the next two weeks, after additional rounds of engineering tests and scientific study.

"The scientists have been let into the candy store," he said.

One of the most interesting characteristics of the site is that it's shot through with light-toned veins of calcium-rich material. "On Earth, forming veins like these requires water circulating in fractures," said Nicolas Mangold of the Laboratoire de Planétologie et Géodynamique de Nantes in France. Mangold is a member of the team behind Curiosity's laser-equipped Chemistry and Camera instrument, or ChemCam.

'A whole different world'
Grotzinger marveled at how different the terrain is from the spot where Curiosity landed, even though both are within Mars' 96-mile-wide (154-kilometer-wide) Gale Crater. The rover's current base of operations, nestled in a shallow depression called Yellowknife Bay, has a type of bedrock that cools more slowly each night than the surrounding terrain. "We don't know what's causing the change," Grotzinger said.

"It's like we entered a whole different world," he said.

The drill at the end of Curiosity's 7-foot-long (2.1-meter-long) robotic arm has not yet been used, but mission managers will command it to drill a series of holes going as deep as 2 inches (5 centimeters) into the rock. The first test holes will serve to clean off any leftover earthly contamination, Cook said. Grotzinger said the drill will eventually produce scientific samples to be fed into the rover's onboard chemical labs, known as CheMin and SAM.

"What we're hoping to do is sample both the vein-filling material as well as what we call the country rock around it," he said.

Before Curiosity's landing, NASA reported that small amounts of Teflon and other material from the drill might contaminate the rock samples. On Tuesday, Cook said the scientists "could work around" the contamination issue by accounting for the unwanted chemicals when they did their analysis.

Curiosity's two-year-long primary mission is aimed at determining whether Mars could have had the chemical building blocks required for life as we know it. Eventually, the 1-ton rover will make its way to a 3-mile-high (5-kilometer-high) mountain in Gale Crater, but Grotzinger said scientists wanted to take ample time to investigate the mysteries they're finding along the way.

More about Curiosity's mission:

• Family gets back down to Earth after living on Mars time
• Rover gives Martian rock its first brushoff
• Curiosity studies a 'flower' on Mars
• Cosmic Log archive on Curiosity

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

Slideshow: Curiosity's space odyssey to Mars

Trace the Curiosity rover's journey to Mars and see the pictures that the six-wheeled robot has sent back from the Red Planet.

Launch slideshow

A California family's journey on Mars time had its ups and downs, but NASA flight director David Oh says he's glad he took his wife and kids on the ride.

"My kids loved it, I loved it, and I think it served to bring the family together," Oh told NBC News on Friday.

Oh is one of the flight directors for NASA's $2.5 billion Mars Science Laboratory mission, which sent the Curiosity rover on a two-year quest to determine whether the Red Planet ever had the chemical ingredients required for life as we know it. Each Martian day, or sol, is 39 minutes and 35 seconds longer than an Earth day. So, to stay in sync with the mission's initial phase, the team at NASA's Jet Propulsion Laboratory in Pasadena, Calif., was put on a Martian schedule for the first 90 sols.

That meant that Oh's workday quickly fell out of sync with Earth time. To make it easier on himself, and on his wife and three children, the Oh family decided to spend 30 sols on Mars time.

"The kids weren't going to get to see Daddy for long periods of time," Oh's wife, Bryn, said. "It just seemed like the right thing to do," 

The time warp meant that the family dinner could take place at 4 p.m. PT, or 4 a.m., depending on how the Martian day meshed with their earthly schedule. But it also meant the Oh children — 13-year-old Braden, 10-year-old Ashlyn and 8-year-old Devyn — had lots of quality time to learn about what Dad is doing.

"Curiosity's mission is to go try and find life on another planet, which is totally cool," Ashlyn Oh said.

David Oh said the rest of the family switched back to Earth time in September, a month after Curiosity's landing, to get into sync with the school schedule. "It really felt like we all had gone off on a journey, and we came back," he recalled. But the tough part of Oh's journey was just beginning: He had to stay on Mars time for an additional 60 sols, and during that period he struggled to juggle his work duties and family time. He remembered some days when he got just four hours of sleep at a time.

"I was in a state of continual jet lag for the last couple of months," he said.

Finally, in November, Curiosity's mission team shifted back en masse to an Earth-day schedule. It took Oh a couple of days to adjust, but now he's firmly back on an earthly schedule. The kids are clamoring to live on Mars time again — but that's one trip Oh doesn't plan to repeat anytime soon.

"It's a once-in-a-lifetime experience," he said.

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

NASA / JPL-Caltech / MSSS

This image from the Mars Hand Lens Imager on NASA's Curiosity rover shows the patch of rock cleaned by the first use of the rover's wire-bristle brush on Jan. 6.

NASA's Curiosity rover used the wire-bristle brush on the end of its 7-foot-long robotic arm for the first time over the weekend, to sweep the dust off a patch of rock wide enough to put a soda can on.

Sunday's use of the motorized Dust Removal Tool, or DRT, marks yet another first for the $2.5 billion Mars Science Laboratory mission, which began operations on the Red Planet with Curiosity's landing last August. The mission team selected an easy target for the tryout: a flat patch of rock known as "Ekwir_1" in the Yellowknife Bay area of Mars' Gale Crater, where Curiosity has been spending the past few weeks.

"We wanted to be sure we had an optimal target for the first use," Diana Trujillo of NASA's Jet Propulsion Laboratory, the mission's activity lead for the DRT, explained in today's status report. "We need to place the instrument within less than half an inch of the target without putting the hardware at risk. We needed a flat target, one that wasn't rough, one that was covered with dust. The results certainly look good."

The area cleaned by the DRT measured about 1.85 inches by 2.44 inches (47 by 62 millimeters). In addition to the brush, the end of Curiosity's robotic arm is equipped with a percussive drill, a close-up camera known as the Mars Hand Lens Imager, the Alpha Particle X-ray Spectrometer and a dirt scooper.

The rover team is evaluating several rocks in the area as potential targets for the first use of the drill sometime in the next few weeks. Brushing off potential targets will be part of the preparation for that drilling operation.

The primary aim of Curiosity's two-year mission is to sample rocks, soil and the atmosphere at Mars' Gale Crater to determine whether the chemical requirements for life could have been present there billions of years ago.

More about Curiosity's mission:

• Tiny 'Martian flower' stirs up some buzz
• Curiosity spends the holidays at 'Grandma's House'
• Rover finds organic compounds, but are they from Mars?
• Cosmic Log archive on Curiosity's Mars mission

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.