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

Jim Urquhart / Reuters

Members of the Crew 125 EuroMoonMars B mission return after collecting geological samples for study at the Mars Desert Research Station in the Utah desert on March 2. The mission is meant to simulate what explorers will face during an eventual mission to the Red Planet.

NASA says it could be another 20 years before humans touch down on Mars, but in a sense, the Mars Society has been exploring the red planet for more than a decade — in Utah.

The nonprofit society's Mars Desert Research Station, near Hanksville, Utah, has been home to 126 crews since the Mars-style habitat was erected in 2002. The idea behind the experimental station is to test the tools and techniques that could come into play during eventual human expeditions to the real Red Planet. Each expedition crew consists of roughly a half-dozen volunteers who spend about two weeks in the Utah desert, conducting real research on a make-believe Mars.

Utah's desert is one of several locales around the world that are thought to be sufficiently Mars-like to teach researchers about the far more extreme conditions on the cold, dry planet. Other locales for Mars simulations include the Canadian Arctic, Antarctica, Norway's Svalbard Peninsula, caves on the Italian island of Sardinia, and even a lab in Russia.

The crew members for such simulations range from NASA researchers to students who hope to walk on Martian soil someday. Another would-be Marsonaut is Reuters photographer Jim Urquhart, who has long yearned to take pictures of the Mars Desert Research Station and its crew. "I had tried for years to go, but my story pitches never made the cut," he said Monday in a blog posting. This month, Urquhart finally got the green light from his editors, in part because "science and space exploration have become sexy again," he said.

Urquhart came away impressed by the volunteer astronauts. "I kept thinking to myself that this group of six embodies so much of what I wish I could become," he said. "They were passionate and chasing their dreams."

Check out these pictures — and Urquhart's blog posting — for more about his visit to Mars in the Utah desert.

Jim Urquhart / Reuters

The night sky whirls above the Mars Desert Research Station outside Hanksville, Utah, in a long-exposure photo. The station is designed to reflect the type of habitat that would be constructed on the Red Planet for future explorers.

Jim Urquhart / Reuters

Csilla Orgel, a geologist, collects samples for study in the Utah desert.

Jim Urquhart / Reuters

Members venture out in their simulated spacesuits to collect samples.

Jim Urquhart / Reuters

Crew members return to the Mars Desert Research Station after a simulated Marswalk.

Jim Urquhart / Reuters

Crew members prepare a meal inside the Mars Desert Research Station. The mock astronauts wear simulation spacesuits when the venture outside, but work in shirt sleeves when they're inside the habitat.

Slideshow: Month in Space: February 2013

Get a look at the moon's glories, interplanetary vistas and other outer-space highlights from February 2013.

Launch slideshow

Chris Smith / NASA file

An artist's conception shows a comet streaking through Martian skies.

It sounds like an "Armageddon" sequel, set on Mars instead of Earth: A supermassive doomsday comet is heading toward the planet in 2014, and there's nothing anyone can do about it. Not even Bruce Willis.

The comet presents a good-news, bad-news situation for the Red Planet, and for us earthlings as well. NASA says Comet 2013 A1, also known as Comet Siding Spring, is almost certain to miss Mars on Oct. 19, 2014. However, there's still a chance — a less than a 1-in-600 chance — that Mars could be hit, due to the remaining uncertainty about the comet's path. That uncertainty is likely to be cleared up over the next few months, eventually resulting in an all-clear.

Even if the comet did hit, there'd be no negative effect on Earth. However, the "Marsageddon" scenario is already adding to the concern that was generated by last month's Russian meteor blast and a near-miss by a larger asteroid.

The case of Comet Siding Spring led Henry Vanderbilt, founder of the Space Access Society, to ask a scary what-if question. "If it was coming straight at us (no more or less likely than it coming straight at Mars), and given our existing space capabilities, could we do anything about it other than prepare to die?" he wrote in a posting to the Moon and Back blog. "The short answer is: Maybe."

The comet's size is the most worrisome part of the story. Based on its observed brightness, astronomers estimate that the iceball could be anywhere from 9 to 30 miles (15 to 50 kilometers) in diameter. In comparison, the asteroid that's been blamed for killing off the dinosaurs 65 million years ago is thought to have been 6 miles (10 kilometers) in diameter.

A direct hit on Mars' backside wouldn't tear the planet apart, but it would produce an explosion that Bad Astronomy's Phil Plait estimates at somewhere around a billion megatons of TNT. That would create a huge crater, blast tons of debris into space and perhaps set off a flood reminiscent of the one that washed over Marte Vallis millions of years ago.

On Earth, the impact would be a civilization-killer.

How do you stop something like that? Scientists have proposed a variety of deflection techniques for smaller objects, when the collision threat can be detected years or even decades in advance. Those techniques range from space-based gravity tractors, to paintball shooters, to laser blasters, to laser bees, to solar sails, to "Armageddon"-style nuclear bombs. Just this week, Iowa State University's Asteroid Deflection Research Center proposed a $500 million mission to test a nuclear-armed asteroid interceptor.

"It's not a laughing matter," center director Bong Wie said in a news release.

There would definitely be no one laughing if a 20-mile-wide comet were coming at us with less than two years of advance warning. In that scenario, the only realistic option would be hydrogen bombs, and lots of them. Vanderbilt estimates it would take about 250 megatons' worth of energy to divert an object like Comet Siding Spring. At 1 to 5 megatons per bomb, that would mean 50 to 250 bombs from the nuclear powers' stockpile. 

"Whether we can effectively apply that energy to successfully divert the comet, we just don’t know," Vanderbilt wrote. "The problem has been studied a fair amount, and the answers vary. Nobody’s actually tested it. We would, under the circumstances, have little choice but to try."

For the time being, Comet Siding Spring is shaping up as a huge near-miss: NASA's Jet Propulsion Laboratory's latest estimate has it missing Mars by about 31,000 miles (50,000 kilometers) — and at that distance, not even the debris flying off the comet is expected to affect the Red Planet or the probes flying around it. It helps that the comet's tail will be pointing away from the planet, as explained in this blog posting by the Planetary Society's Emily Lakdawalla.

The comet would make an impressive sight if you were watching it from Mars (magnitude zero or brighter), and NASA's rovers will likely be doing just that. But it isn't expected to reach naked-eye brightness for earthly observers. Chances are that Comet Siding Spring will make its biggest impact as another reminder that we have to address the perils posed by cosmic threats sooner or later.

Considering what's happened over the past month, how many more reminders do we need?

More about cosmic threats:

• What's worse, asteroids or comets?
• Experts: Don't blame comet for culture's doom
• Cosmic Log archive on asteroids

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.

Golden Spike

An artist's conception from the Golden Spike Company shows a lunar lander in the foreground, and a moonwalking astronaut in the background.

Selling trips to the moon? Sending astronauts to Mars and back? These sound like 1960s-era science fiction adventures, but they're actually in the works for later this decade. Will these privately backed projects get off the ground? That's the billion-dollar question.

The Golden Spike Company says it's in talks with one corporation and more than one space agency about sending a two-person expedition to the moon in the 2020 time frame, at a cost of $1.4 billion per mission. Meanwhile, the Inspiration Mars Foundation is getting ready to launch a man and a woman, preferably a middle-aged married couple, on a round-trip flyby past Mars in 2018.

The two ventures are the focus of Wednesday night's installment of "Virtually Speaking Science," a talk show that airs online via BlogTalkRadio with a live audience in the Second Life virtual world. I'm your host, and my guests are Taber MacCallum, Inspiration Mars' chief technology officer; and Doug Griffith, general counsel for Golden Spike.

The hour-long show starts at 9 p.m. ET (6 p.m. PT), but if you miss the live program, never fear: You can always download the podcast from BlogTalkRadio's archive or iTunes.

Both Golden Spike and Inspiration Mars are getting advice and moral support from NASA, but the financial support is coming from elsewhere. The lunar venture expects to bootstrap its way to profitability by selling its services — and initially through an Indiegogo crowdfunding campaign aimed at raising $240,000 (one dollar for each mile to the moon) by late April. So far, more than $7,500 has been contributed.

To Mars and back
Inspiration Mars is relying on seed money from California millionaire Dennis Tito, who became the first tourist to visit the International Space Station in 2001. Tito said his effort to send a spacecraft zooming past Mars during a favorable planetary alignment in 2018 is purely philanthropic, with the goal of inspiring future generations of Americans.

MacCallum, who took part in the Biosphere 2 experiment in 1991-1992 and went on to become a co-founder of Paragon Space Development Corp., said he's already noticed the inspirational effect.

"I keep hearing people say, 'This is the kind of thing America used to do, and maybe now we can do it again.' It's like we touched on a sore spot, and the reaction has been ... almost too positive," MacCallum said.

He said Tito's aim was merely to get some introductory exposure for the concept, in hopes that all the kinks can be worked out in time to make the 2018 deadline. Tito has committed to supporting the venture for its first two years, but he needs to raise the rest of the money for what's rumored to be a billion-dollar mission.

The team hasn't yet worked out the procedure for selecting the crew, but MacCallum said more than 100 applications have already been sent in — including some candidates with jaw-dropping credentials. "There are some where you say to yourself, 'Oh, my gosh!'" MacCallum told me. "Hey, listen, it's suddenly cool to be a middle-aged couple."

To the moon
Unlike Inspiration Mars, Golden Spike is set up as a business, which will ultimately have to be supported by paying customers. The idea is to provide two-person trips to the moon for roughly the same cost as today's robotic missions to the moon. Golden Spike aims to do that by employing high-tech, low-cost hardware as well as a relatively low-risk mission architecture. The company plans to pre-position a lander in lunar orbit, and only then send the crew and their moon-and-back booster on a subsequent pair of launches.

"Before it even launches, we know that the lander is working," said Griffith, who is drawing upon years of experience in space and aviation law.

Griffith said Golden Spike will serve as the outer-space analog of, say, United Airlines, contracting with other companies for flight hardware. The company is working on design studies for launch vehicles, landers and other equipment. It's also talking with potential customers — and trying to convince the skeptics that it's really possible to put people on the moon, almost half a century after NASA did it in 1969.

"The consensus seems to be that it's doable within the prices we're talking about," Griffith said. "All of the skepticism seems to be about whether there are space agencies or billionaires who are willing to pay the price. That is the big unknown. ... I think we'll know in fairly short order whether the skeptics are right or wrong."

Griffith said Golden Spike's game plan calls for signing up its first customers for "right of first refusal" deals by the middle of the year, and getting its first flight contract by the end of this year.

"Our operating premise is not that we keep sliding things back," Griffith told me. "Our operating premise for now is, it's go time."

Are Golden Spike and Inspiration Mars ready for takeoff, or will we have to wait for NASA to send astronauts to a near-Earth asteroid in the mid-2020s, and to Mars and its moons in the mid-2030s? Listen in to "Virtually Speaking Science" and feel free to weigh in with your own views, either by taking part in the live show or by leaving your comments below.

'Virtually Speaking Science' podcasts:

• Sean Carroll and Matt Strassler on physics' X Files
• Ig Nobel's Marc Abrahams on weird science in 2012
• Paul Doherty on Curiosity and the year in science
• Shawn Lawrence Otto on the election and the climate issue
• Sean Carroll on what lies beyond the Higgs boson
• Alan Stern on the Uwingu mystery space venture
• George Djorgovski on the future of immersive virtual reality
• JPL's Dave Beaty previews Curiosity's mission on Mars
• SETI Institute's Seth Shostak about aliens and UFOs
• Paul Doherty on solar eclipses and the transit of Venus
• Veronica Ann Zabala-Aliberto on spaceflight and Yuri's Night
• JPL's Dave Beaty on the search for life on Mars
• Shawn Lawrence Otto on science and politics
• Ig Nobel impresario Marc Abrahams on silly science
• Rocket scientist Robert Zubrin on Mars exploration
• Propulsion expert Marc Millis on interstellar spaceflight
• Sean Carroll on the puzzles facing physicists
• Rand Simberg on the private-enterprise vision for spaceflight
• Martin Hoffert on the future of energy policy
• George Djorgovski on science in virtual worlds
• Alan Stern on suborbital research and NASA's mission to Pluto
• Col. 'Coyote' Smith on the outlook for space solar power
• Tim Pickens on rocket ventures and the Google Lunar X Prize

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.

"Virtually Speaking Science" airs on Wednesdays on BlogTalkRadio, with a live audience in the Exploratorium's Second Life auditorium. In addition to Alan Boyle, the hosts include Tom Levenson, director of MIT's graduate program in science writing; and Jennifer Ouellette, science writer and "Cocktail Party Physics" blogger.

Millionaire space tourist Dennis Tito and his partners have had to tell questioners repeatedly that they're not "crazy" or "nuts" to think they can launch a man and a woman to Mars and back by 2019 — but if the Inspiration Mars Foundation's "Mission for America" succeeds, it may well be because it's just crazy enough. 

Other private space ventures, ranging from SpaceX to the Golden Spike Company and Planetary Resources, are depending on turning a profit someday through the sale of rocket flights, or missions to the moon, or water and precious metals mined from asteroids. Tito, in contrast, freely admits the 501-day mission is a "one-shot deal" that's unencumbered by a long-range business plan. He's committed to supporting the five-year development effort for the first two years, during which time he and the rest of the team will try to raise the money and perfect the technologies for the three more expensive years to follow.

So how much is that going to cost him? "Who knows?" Tito said.

Tito expects to look in all the usual places for funding, including sponsorships, the sale of media rights, the sale of scientific data from the flight and private contributions. A 6-year-old boy has already sent in one of the first contributions, amounting to $10. "This is my Apollo," he was quoted as saying.

If Tito had a dime for every time the Apollo era was invoked on Wednesday, he'd be making a good start toward a fund-raising goal that is estimated to range around $1 billion. Some questioned whether the non-stop Mars flyby would be worth it, on scientific or economic grounds. But that's missing the point: Like Tito's eight-day trip to the International Space Station in 2001, the payoff would be purely inspirational rather than scientific.

"Inspiration Mars reminds me of Apollo 8 in 1968, going around the moon," software billionaire Charles Simonyi, who spent tens of millions of dollars buying two flights to the International Space Station, said in a Twitter update. "Inspiration is a goal for humans, science should be left to the rovers."

In a follow-up exchange of messages, Simonyi told NBC News that he wouldn't be spending millions more to support Tito's effort. He noted that his philanthropic foundation, the Charles Simonyi Fund for Arts and Sciences, "has spent the $100M it had in 10 years, as planned."

"But I think Inspiration will have broad-based support," he said. "Very exciting."

NASA also voiced moral support, saying in a statement that the Inspiration Mars mission was "a testament to the audacity of America's commercial aerospace industry and the adventurous spirit of America's citizen-explorers." Inspiration Mars plans to pay NASA for access to the agency's know-how about thermal protection systems for re-entry, said Taber MacCallum, the foundation's chief technology officer and a co-founder of Paragon Space Development Corp.

Inspiration Mars

A graphic from Inspiration Mars shows the expected path of a spacecraft going around the far side of Mars during a 501-day round trip launched in 2018.

Technical issues
In addition to the craziness about the money, there's the craziness about thinking that the rocket and crew capsule will be ready to launch on Jan. 5, 2018, when the planets literally align. A launch on or around that date would result in a straightforward, no-fuss trajectory that would come within 100 miles of Mars' backside on Aug. 20, 2018, and bring the spacecraft back to Earth on May 21, 2019. The mission plan is outlined in a feasibility analysis prepared for an aerospace conference, but Tito and his co-authors acknowledge that the space vehicles cited in the paper don't yet exist.

The paper says it'd be feasible to use the still-under-development SpaceX Falcon Heavy rocket and a modified SpaceX Dragon capsule, with a Bigelow-type inflatable module added on. But MacCallum acknowledged that Inspiration Mars was still talking with potential industry partners on what the launch configuration might be. He said choosing that configuration, as well as designing the life-support system and the thermal protection system, were high priorities on the to-do list.

MacCallum stressed that simplicity would be the key. "This is going to be a Lewis and Clark mission to Mars," MacCallum said. "Keep it bare bones, keep it simple."

Tito provided scant details about the five-year development timeline but said that the mission would rely upon technologies developed for flights to the space station. "It uses low-Earth-orbit architecture ... and we're just adapting it in effect to a very large Earth orbit," he said. Responding to questions about the tight time frame, Tito pointed out that Apollo 8's around-the-moon mission took place just a year after the first unmanned test launch of NASA's Saturn 5 rocket in 1967. (However, it took five years to design and develop the Saturn 5 in preparation for that first launch.)

The trajectory for the "Mission for America" is designed such that only minor course corrections would be required along the way. There'd be no engine burn required for the return leg of the trip, and no deorbit burn. However, the spacecraft's speed at re-entry would be 32,000 mph (14.2 kilometers per second), or almost twice as fast as the space shuttle's re-entry speed. And if the trajectory went slightly off for some reason, there's a chance that the capsule could slam into Mars — or miss Earth entirely on the way back, dooming the crew to another deadly circuit. 

Who will go?
Jonathan Clark, a former NASA flight surgeon who has served as an adviser for several space ventures, acknowledged that "there's no question this is a risky and bold endeavor." He estimated that there was a roughly 7 percent chance that one of the two astronauts on board would experience a serious medical issue during the mission. That's the big reason why it'd be a two-person trip rather than a solo flight: so that one of the astronauts could serve as the backup for the other. That, and the fact that it'd be an awfully lonely year and a half for just one astronaut.

Tito insists that the two-person crew should consist of a man and a woman, preferably a married couple, in order to combat the loneliness and reduce the risk of crew incompatibility. Tito joked that one of the mission's media deals might involve Dr. Phil giving "marital advice" to the couple while they're in flight.

Like most of the spacecraft components, the crew would be American, Tito said. He described the key attribute for prospective crew members as "the Right Stuff times 10." MacCallum, meanwhile, said the astronauts would have to have "an amazing mechanical skill" in order to keep the onboard systems running smoothly. MacCallum's wife, Paragon co-founder Jane Poynter, said they'd have to be "even-keeled" to get along for a year and a half while cooped up in the outer-space equivalent of an RV. (MacCallum has said that he and Poynter would be interested in taking the Mars trip themselves.)

Clark estimated that it would take six months to a year to work out the process for crew selection.

Tito faced repeated questions about why he was taking on this mission — and it was clear that American pride was part of the equation. One reporter asked whether Tito merely wanted to get to Mars before the Chinese. "Beat China to Mars?" he replied. "Wouldn't I want to do that? Wouldn't I want America to do that? Wouldn't you want America to do that?"

He also noted that if Inspiration Mars missed the launch opportunity in 2018, the next opportunity for a 501-day mission wouldn't come around again until 2031. "If we don't fly in '18, the next low-hanging fruit is in '31, and we better have our crew trained to recognize other flags," he said. "They're going to be out there."

Update for 8:25 p.m. ET: Tito's plan has also gotten a vote of support from Apollo 11 astronaut Buzz Aldrin, who is writing a book titled "Mission to Mars: My Vision for Exploration." The Washington Post's Brian Vastag quotes Aldrin as saying, "I've talked with Dennis, and I've strongly encouraged him. The purpose is to inspire, to say we're going to do something and then we do it." It doesn't hurt that the schedule calls for the round trip to end two months before the 50th anniversary of the Apollo 11 moon landing.

Update for 9:50 p.m. ET: Here's another vote of support from planetary scientist Alan Stern, president and CEO of the Golden Spike Company: "Very excited about Inspiration Mars and the way they and we at Golden Spike are both breaking the mold in human space exploration in this country — and around the world," Stern wrote in an email. Golden Spike is working on a plan to launch missions to the moon at a cost of $1.4 billion per mission (that's $700 million per seat for a two-person flight). The company is currently in the midst of an Indiegogo crowdfunding campaign. 

More about flights to Mars:

• Married couple wanted for Mars trip
• 500-day mock Mars trip raises problem
• Does Mars need women? Russians say no

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.

Millionaire space tourist Dennis Tito's plan to send two astronauts on a 501-day flight that zooms past Mars and swings back to Earth would set plenty of precedents on the final frontier — but the most intriguing precedent might have to do with the astronauts that are to be sent: one man and one woman, preferably a married couple beyond childbearing years. We're talking about sex in space, folks.

And if that's not intriguing enough, consider this: There are already a couple of candidates for the job.

"We'll certainly throw our hat in the ring," said Taber MacCallum, who's a member of the development team for the 2018 mission that Tito has in mind.

MacCallum and his wife, Jane Poynter, were crew members together in Biosphere 2, the controversial two-year-long experiment in long-term environmental containment. They went on to become co-founders of Paragon Space Development Corp., a company specializing in life-support systems for spacecraft. Their expertise in life support is why they're involved in Tito's "Mission for America," which was officially unveiled on Wednesday at the National Press Club in Washington. But it just so happens that they also fit the profile for the trip: Poynter is about 50, and MacCallum will turn 49 on July 20, the anniversary of the Apollo 11 moon landing.

The couple won't be the only candidates in the running. "When we tell people we're proposing to send a man and a woman on a mission to Mars, as a married couple, people line up. ... That chord gets struck over and over again," MacCallum said.

Paragon

Taber MacCallum and his wife, Jane Poynter, are part of the planning team for a mission to Mars in 2018. They're also potential candidates to take the trip.

MacCallum explained that Tito wants the crew on humanity's first trip to Mars to be representative of humanity, and because the current concept for the trip calls for two spacefliers, that means a man and a woman. A married couple would be ideal, MacCallum said, because of the "whole issue of companionship." MacCallum didn't refer specifically to sex, but that would presumably be part of the companionship package.

"When you're out that far, and the Earth is a tiny, blue pinpoint, you're going to need someone you can hug," Tito told Space.com. During Wednesday's briefing, Tito told reporters that he envisioned Dr. Phil giving the couple "marital advice" during the trip.

In addition to their experience with life-support systems (and with each other), MacCallum and Poynter can draw upon their experience with life in isolation during the Biosphere 2 experiment in Arizona, which lasted from 1991 to 1993. The isolation inside a two-room spacecraft for 501 days will be even deeper. Even though the Biosphere 2 crew was separated from the outside world, "we could walk out at any time," MacCallum pointed out.

That's not the only challenge: Even with radiation shielding in place, the round trip to Mars is likely to involve exposure levels higher than NASA's limits, MacCallum said. (That's why the astronauts should be beyond their childbearing years and willing to accept an increased risk of cancer.)

Then there's the exposure to the health effects of long-term weightlessness, including bone loss and muscle loss. The astronauts who fly past Mars will surpass Soviet cosmonaut Valery Polyakov's 437-day record for continuous time in microgravity, set in 1994-1995 aboard the much roomier Mir space station. 

"We're definitely pushing boundaries," MacCallum said. "It's definitely going to be hard and challenging. But we can rely on elegance and simplicity."

When, where and how?
The details of the mission plan have come to light just in the past few days, but MacCallum said that Tito has been mulling over the idea for years. Tito started out as an engineer at NASA's Jet Propulsion Laboratory, helping to design trajectories for the Mariner missions to Mars in the 1970s. Then he put his math genius to work in the investment world, building California-based Wilshire Associates into a multibillion-dollar powerhouse. In 2001, he spent around $20 million of his fortune for a seat on the Russian Soyuz spacecraft traveling to and from to the International Space Station.

After his eight-day space tour, Tito got back to business. But he also started working out a trajectory that could send a spaceship directly from Earth to Mars for a fly-by within 100 miles (160 kilometers) of the Red Planet's surface, and then back to the home planet 501 days after launch. Once the spaceship was on its way, only minor course corrections would be needed. There'd be no need for undocking or redocking ... no landing ... no do-or-die engine burn for the return from Mars.

There's one big catch, though: The trip will have to be started when the planets were aligned just right. One opportunity will come in 2016. Then there's another one in 2018. After that, the next chance won't come around until 2031.

Planning for a launch in January 2018 looked particularly attractive, and not just because that could plausibly provide enough time to put the mission together. That's also a time frame when solar activity is expected to be at a minimum, reducing the level of radiation exposure. So Tito assembled a team from Paragon as well as NASA's Ames Research Center and other space ventures to flesh out the mission plan.

The plan calls for launching the two astronauts in a crew capsule with a transfer rocket stage. If the launch vehicle is powerful enough — say, the size of SpaceX's Falcon Heavy — the upper stage and the crew capsule could be launched in one go. If the rocket doesn't have that much oomph, the capsule and the upper stage could be launched separately and then linked up in Earth orbit for the push onward to Mars.

Inspiration Mars

An artist's conception shows how the spacecraft for the Inspiration Mars Foundation's "Mission for America" might be configured — with a crew capsule, an inflatable module similar to the ones built by Bigelow Aerospace, and an attached upper stage that could provide radiation shielding. The actual design has not yet been set.

"We only need to attach the upper stage. There's no need to get rid of it," MacCallum said. In the right configuration, that upper stage could even provide some of the required shielding from solar radiation and heating, he said.

The crew's 600 cubic feet of living space would include a capsule for launch and re-entry, with a well-shielded sleeping quarters that could provide a safe haven if solar storms erupted. There would be a habitat module — perhaps an inflatable module like the one that Bigelow Aerospace has been working on for NASA's use. The main idea is to keep the crew compartment as simple as possible while providing all the necessary amenities for a 501-day trip. "It's a '55 Chevy," MacCallum said.

To test the feasibility of the plan, Tito and his colleagues looked at the specifications for the Falcon Heavy as well as a modified version of SpaceX's Dragon capsule. But MacCallum emphasized that the team was not committed to using SpaceX hardware. He said the idea was getting a "great response" from a variety of aerospace companies. "If this mission is going to happen, they want 'their vehicle' to do it," McCallum said.

How much? And why?
MacCallum characterized the mission as "purely philanthropic," with the aim of inspiring future scientists and engineers as well as bridging the gap in NASA's plans for exploration beyond Earth orbit. NASA's current timetable calls for astronauts to go no farther than the International Space Station until 2021 at the earliest. Even though the Mars-and-back mission wouldn't make any stops, the trip could produce useful scientific data — and an adventure as grand as the Apollo moonshots of the '60s and '70s.

"I think we really need what Apollo did for America, but we didn't realize it while we were doing Apollo," MacCallum said.

Toward that end, Tito set up the Inspiration Mars Foundation. "He has committed to funding the first two years of this development, and he is committed to finding the rest of the money," MacCallum said. "Dennis is already getting tremendous interest in this mission from people of means."

The foundation is also looking into media deals and sponsorships. "Farmers Insurance cut a $700 million deal for the naming rights for a stadium," MacCallum noted. "Wow ... that's a not-insubstantial part of the money that we're talking about."

How much money are we talking about? MacCallum quoted Tito as saying "it's a fraction of what Curiosity cost," with reference to NASA's $2.5 billion robotic mission to Mars. Other reports have put the cost in the range of $1 billion or so — which is far less than the projected price tag for the crewed missions NASA plans to send to Mars in the 2030s.

MacCallum emphasized that Tito's "Mission for America" was meant to support America's space agency, not compete with it. "This mission is only even remotely contemplatable because of all the work that NASA has done on the International Space Station," he said. And NASA is getting something in return: MacCallum said Inspiration Mars is paying NASA for access to thermal protection technologies developed by the space agency.

Even if MacCallum and Poynter aren't picked to go on the flight, it sounds as if they'll be having the adventure of their lives over the next five years. "I feel so thrilled every day to be working with these people," MacCallum said. "It's just fabulous."

More about sex, Mars and spaceflight:

• Outer-space sex carries complications
• How a TV show could create a Mars colony
• Astronauts could survive Mars radiation

Is Dennis Tito's idea crazy? Check out this follow-up posting for a reality check.

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.

Mikhail Metzel / AP file

Millionaire spaceflier Dennis Tito flashes a thumbs-up sign during final preparations for his 2001 flight to the International Space Station. Now Tito is reportedly contemplating a mission to Mars.

By Alan Boyle,
Science Editor, NBC News

Dennis Tito, the millionaire investment whiz who became the first paying passenger to visit the International Space Station in 2001, has worked out a plan to send two astronauts to Mars and back without stopping. However, the privately backed 501-day flight would have to be launched in 2018 — or wait until the 2030s.

Details about the Red Planet flyby are trickling out in advance of a Washington news conference next week.

First word of the venture came out in a media advisory passed along by the SpaceRef website on Wednesday. The advisory from the Texas-based Griffin Communications Group describes a "Mission for America" that would capitalize on a favorable orbital opportunity to launch a round-trip mission to Mars in January 2018.

The advisory includes an invitation to attend a news conference at 1 p.m. ET Feb. 27 at the National Press Club in Washington, issued by the Inspiration Mars Foundation, which is described as a "newly founded nonprofit organization led by American space traveler and entrepreneur Dennis Tito."

Tito, a former rocket engineer, made his fortune as the founder of Wilshire Associates, a multibillion-dollar investment firm based in California. He made history in 2001 when he paid a reported $20 million for a ride aboard a Russian Soyuz spacecraft to the space station. At the time, the eight-day round trip was highly controversial and required changes in the policies governing space station operations. Since then, six other high-net-worth individuals have taken similar flights with little or no controversy. The current published price for such flights is upwards of $40 million.

In the nearly 12 years since his flight, Tito has taken a relatively low public profile in the private-sector spaceflight industry. Meanwhile, other millionaires and billionaires, ranging from SpaceX's Elon Musk to Amazon.com founder Jeff Bezos to Microsoft co-founder Paul Allen, have been in the vanguard. 

Little is known about the Inspiration Mars Foundation, and the name doesn't turn up in databases for tax-exempt nonprofit organizations. The Internet domain names "InspirationMars.com" and "InspirationMars.org" were registered anonymously last October. But other than that, the only information that could be gleaned about Inspiration Mars comes from the media advisory, which says it's "committed to accelerating America's human exploration of space as a critical catalyst for future growth, national prosperity, new knowledge and global leadership."

"This 'Mission for America' will generate new knowledge, experience and momentum for the next great era of space exploration," the advisory said. "It is intended to encourage all Americans to believe again, in doing the hard things that make our nation great, while inspiring youth through Science, Technology, Engineering and Mathematics (STEM) education and motivation."

In addition to Tito, the speakers listed for next week's news briefing include Taber McCallum and Jane Poynter, who are veterans of the Biosphere 2 life-containment experiment and the top executives at Paragon Space Development Corp., which develops life-support systems for spacecraft. Jonathan Clark, a former NASA flight surgeon who now serves as an adviser for several space ventures, is also due to appear. Veteran TV journalist Miles O'Brien, who was once in line to take a trip to the space station, is to serve as moderator.

Update for 10:58 a.m. ET Feb. 21: The media advisory doesn't describe the specifics of the proposed mission, but spaceflight consultant Jeff Foust, publisher of the online NewSpace Journal, has come across information that sheds lots of additional light on Tito's plans. It turns out that Tito is due to give a presentation at the IEEE Aerospace Conference in Montana next month. He and his co-authors discuss the project in a paper prepared for the presentation. Here's a quick rundown of what Foust found: 

The mission would involve a flyby of Mars with a free return back to Earth, without stopping. That type of low-energy trajectory requires a special set of orbital circumstances: The presentation says those circumstances exist for the 2018 opportunity but won't repeat until 2031.  Two astronauts living in spartan conditions could make the 501-day trip in a modified SpaceX Dragon capsule, launched by SpaceX's yet-to-be-flown Falcon Heavy rocket.

Be sure to read Foust's full item on NewSpace Journal.

The plan seems to be just on the edge of doability. Among the questions that come up: Would the Dragon have adequate radiation shielding for the long-duration, deep-space trip? Can the crew cope with long-term isolation in close quarters, as well as the health effects of an extended zero-G trip? Can the Falcon Heavy truly be ready for a Mars trip in time for the 2018 opportunity? And who's going to pay for all this? Although there's no price tag attached to the plan, doing the mission seems likely to require billions of dollars. Tito may be rich, but is he that rich?

Update for 1:05 p.m. ET Feb. 21: Griffin Communications has confirmed the substance of the media advisory but released no additional information. The logistics for next week's briefing at the National Press Club are still being worked out. It's not yet known whether the proceedings will be webcast.

Update for 6:18 p.m. ET Feb. 21: A few more tidbits have trickled out: Even though the IEEE paper focuses on the SpaceX Dragon and Falcon Heavy, that doesn't mean SpaceX's participation in the project is a sure thing. The astronauts could ride on any of a range of space vehicles. One thing is for sure, however: Tito, who is now 72 years old, will not be making the spaceflight himself.

Although the IEEE paper casts the "Mission for America" as a private-sector effort, NASA would play a supporting role in technology development. A source who has been told about Tito's plans said the 2018 effort was not meant to provide competition for NASA's exploration effort, but instead provide support. NASA is working on a long-range program to send astronauts to a near-Earth asteroid in the mid-2020s, and to Mars and its moons in the mid-2030s.

The source was not authorized to speak publicly about Tito's plans, and thus spoke with NBC News on condition of anonymity. 

More about Mars ambitions:

• SpaceX founder wants to send hordes to Mars
• How a TV show could create a Mars colony
• Counting down to a mission to 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 Thu Feb 21, 2013 3:32 AM EST

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.

Bill Ingalls / NASA

A commemorative wreath adorns a monument to the crew of the shuttle Columbia at Arlington National Cemetery in Virginia on Friday, the 10th anniversary of the shuttle's destruction and the astronauts' deaths.

President Barack Obama and NASA's leaders paid a 10th-anniversary tribute to the space shuttle Columbia's fallen astronauts on Friday — and pledged that the lessons learned would be applied to future space odysseys, including eventual trips to Mars.

"As we undertake the next generation of discovery, today we pause to remember those who paid the ultimate sacrifice on the journey of exploration," Obama said in a statement released by NASA. "Right now we are working to fulfill their highest aspirations by pursuing a path in space never seen before, one that will eventually put Americans on Mars."

The shuttle Columbia's catastrophic breakup on Feb. 1, 2003, killed seven astronauts, forced a two-year grounding of the three remaining space shuttles and led to stepped-up safety measures at the space agency. The disaster also led Obama's predecessor, President George W. Bush, to plan for the retirement of the shuttle fleet once construction of the International Space Station was complete. The last shuttle mission flew eight years later, in 2011.

Bush's space vision called for a new generation of vehicles to be built for trips back to the moon by 2020 — but Obama shifted the focus of exploration to a near-Earth asteroid in the mid-2020s, with trips to Mars and its moons starting in the mid-2030s.

'We will never forget'
In his own 10th-anniversary statement, NASA Administrator Charles Bolden said the sacrifices made by the crew of Columbia's last mission will inspire future explorers.

"We will never forget these astronauts, nor all those who have lost their lives carrying out our missions of exploration — the STS-51L Challenger crew; the Apollo 1 crew; Mike Adams, the first in-flight fatality of the space program as he piloted the X-15 No. 3 on a research flight," Bolden said in an agency statement. "These explorers, and their families, have our deepest respect. We work every day to honor and build on their legacy and create the best space program in the world — to infuse it with the life and vitality that they worked so hard to achieve."

Bill Ingalls / NASA

NASA Administrator Charles Bolden looks on as Apollo 11 moonwalker Buzz Aldrin gives a salute during a wreath-laying ceremony at Arlington National Cemetery on Friday. The ceremony paid tribute to astronauts who died in the Apollo 1 fire of 1967 as well as the 1986 Challenger explosion and the 2003 Columbia tragedy.

Slideshow:

Retrace the final, tragic flight of the space shuttle Columbia, from its launch to its catastrophic end on Feb. 1, 2003.

Launch slideshow

On Friday morning, Bolden laid a wreath in honor of the agency's fallen astronauts at Arlington National Cemetery in Virginia, where monuments to the Columbia and Challenger crews have been erected. Earlier in the week, he attended a spaceflight conference held in Israel to honor Ilan Ramon, that country's first astronaut, who died in the Columbia tragedy. The other victims included Columbia commander Rick Husband, William McCool, Michael Anderson, David Brown, Kalpana Chawla and Laurel Clark.

Memorial ceremonies also were conducted in Texas, where the Columbia wreckage fell to earth, and at Kennedy Space Center's visitor complex in Florida. The focal point of the Florida ceremony was the Space Mirror Memorial, which bears the names of NASA fliers who died in the line of duty.

Roots of the tragedy
At that ceremony, Bill Gerstenmaier, NASA's associate administrator for human exploration and operations, acknowledged that the roots of the Columbia disaster went "all the way back to the first shuttle launch in 1981." Even then, NASA knew that ice and pieces of foam insulation could fly off the shuttle's external fuel tank and strike the orbiter — but the fact that no severe damage was done "reinforced the idea that all was well," Gerstenmaier said.

That view changed dramatically when Columbia was felled. Investigators determined that the leading edge of Columbia's left wing was fatally damaged by a piece of flying foam during launch, setting the stage for the breakup 16 days later during atmospheric re-entry. NASA was reminded that "even small problems can surface as major failures," Gerstenmaier said.

"Ten years ago, it would have been easy to pull back from the frontier of space, and say it was too risky to pursue," he said. "Instead, we dedicated ourselves to improving how we pushed the boundaries of space exploration, and we vowed to continue with our eyes open. We cannot be afraid of risk, and we cannot be ignorant of it, either. Our lasting tribute to those we have lost is to carry on with the cause that they believed was worth the ultimate sacrifice."

Other speakers at the Florida ceremony included Evelyn Husband-Thompson, the widow of Columbia's commander, who has since remarried. She recalled how she and other family members anticipated the return of their loved ones on that fateful Saturday morning 10 years ago, only to be jolted into a nightmare of "fear, uncertainty and horror."

NASA

Evelyn Husband-Thompson, the widow of Columbia commander Rick Husband, speaks at a memorial ceremony conducted Friday at the Space Mirror Memorial at Kennedy Space Center's visitor complex.

"The grief journey has been difficult, complicated and surprising," she said. Over the past decade, she has drawn comfort from her friends, her family and her faith. She noted that the Columbia crew's legacy includes educational initiatives, scholarships, museum exhibits, and even the name of the airport near her home in Texas: Rick Husband Amarillo International Airport.

"Just as a forest fire reduces beautiful foliage to ashes, those ashes ultimately become nourishment for new, healthy growth," Husband-Thompson said. "There are indeed small, green shoots of hope that are springing up in our lives."

More about Columbia:

• 10 years later, Columbia's loss still stings
• Shuttle tragedies serve as warnings to NASA
• 10 myths surrounding the Columbia tragedy
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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.