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MSL drill holes
The holes created in a Martian rock by Curiosity’s drill earlier this month, the first uses of the drill since landing. (credit: NASA/JPL-Caltech/MSSS)

From seven minutes of terror to seven months of science

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When NASA’s Mars Science Laboratory mission successfully landed the Curiosity rover on the surface of Mars late in the evening of August 5, it was hailed far and wide as a major success, both for NASA and Mars exploration in general. Getting the one-ton rover safely on the Martian surface required navigating the perilous process of entry, descent, and landing (EDL) that became known, thanks to a NASA video produced prior to landing, as the “seven minutes of terror.” The successful landing burnished NASA’s reputation and turned some of those involved into minor celebrities (see “From terror to triumph”, The Space Review, August 6, 2012).

“Everybody wants to know, ‘Gosh, why does this take so long?’ It’s because we want to be careful and not make mistakes,” Grotzinger said.

For Curiosity’s science team, though, those seven minutes of terror was only the beginning. In the nearly six and a half months since the landing, the mission team has been gradually putting the rover through its paces, testing out its instruments and starting to move across the terrain in Gale Crater. In contrast to the landing of the rover on Mars, where success could be quickly and clearly determined, rover science and operations have proceeded at a slower pace.

“Curiosity is such a complex system that, when you operate it, you just have to take baby steps to make sure that you preserve it for posterity’s sake, because it could last quite a long time. So, therefore, we go slow,” said John Grotzinger, the Caltech geology professor who serves as project scientist for the mission. He was speaking Friday at a press conference during the annual meeting of the American Association for the Advancement of Science (AAAS) in Boston.

He made that same point in a plenary talk later that morning at the conference. “Everybody wants to know, ‘Gosh, why does this take so long?’ It’s because we want to be careful and not make mistakes.”

That deliberate approach to mission operations is evident in one Curiosity’s most recent major milestones, the first use of the rover’s drill. On February 9, NASA announced the rover had collected its first bedrock sample with the drill, boring 6.4 centimeters into a rock dubbed “John Klein,” after a deputy project manager who died in 2011. That came a few days after a test of the drill on a nearby spot on the same rock. Ultimately, the powdered bedrock collected by the drill as it bored into the rock will be delivered to the rover’s instruments.

The emphasis, though, is on “ultimately.” Grotzinger said that they still need to confirm that the samples traveled up the drill stem into chambers that hold the sample until they’re placed in the rover’s Collection and Handling for In-Situ Martian Rock Analysis (CHIMRA), a device that vibrates the material over a sieve to remove particles larger than 150 microns. The remaining sample is then transferred to the rover’s Chemistry and Mineralogy (CheMin) and Sample Analysis at Mars (SAM) instruments for analysis. He said they’re hoping “in the next week or so” to complete that process.

“For us in the surface operations, this is really the equivalent of EDL,” Grotzinger said of the drill test at the press conference. “Instead of seven minutes of terror, you have seven months of hand-wringing to really make sure that it all worked.”

Curiosity is likely to spend at least the next several weeks at its current location, he said. Part of that time will be spent analyzing the sample and doing follow-up studies, which will depend, he said, on how “exciting” the sample turns out to be. An upcoming solar conjunction, when Earth and Mars are on opposite sides of the Sun, thus disrupting radio communications, will also keep the rover at its current location. “We might not be driving until some time quite late this spring,” he said.

“One thing I discovered back in the fall,” Grotzinger said, “is that everybody’s expectations are extraordinarily high for things that only under the most extraordinary conditions would ever discover.”

Another reason for the deliberate pace of Curiosity operations is the belief that Curiosity has a long lifetime ahead of it. Officially, the rover has a two-year prime mission, but the spacecraft is designed to operate for far longer, and thus as long as it’s good condition, project officials expect NASA to extend the mission perhaps far beyond that initial two years. “I think the agency feels the mission has gone very well,” Grotzinger said. “They've told us they’re willing to support it beyond the nominal mission lifetime.”

That support for a long-term mission, he said, allows them “to think a little bit more strategically” about mission operations. The original mission plan, for example, was to drive from the landing site in the direction of the mountain in the center of Gale Crater, officially designated Aeolis Mons but called Mt. Sharp by the project team. After landing, though, the project designed to drive in the opposite direction, towards a junction of three different terrains dubbed Glenelg.

The science that they’ve collected so far has justified that decision, Grotzinger said. “It has paid a lot of dividends in terms of what we view to be an exciting, potentially habitable ancient environment, so we’re going to explore that thoroughly,” he said.

At the AAAS meeting, Grotzinger didn’t reveal any findings from the mission not already released previously by NASA. Asked at the press conference about differences in color seen in the powered bedrock left behind from the recent drilling, which showed grayish material in contrast to the red on the surface, Grotzinger said analysis of data was ongoing. “I think what we want to do is get all our observations together and present it in one go, so hopefully within a month’s time you should head something about that,” he said.

That timeline would align with the upcoming Lunar and Planetary Science Conference (LPSC) in Houston, which starts a month from today. Grotzinger said that at an “all hands” meeting of the science team earlier in the week, they reviewed the results they plan to present at the conference.

“It may take us a long time to get there,” he said of Mt. Sharp, “but we do intend to go there.”

Grotzinger’s reticence to divulge details about rover science might also be rooted in what happened in November, when he told a visiting reporter that one of the rover’s instruments had produced data that “is gonna be one for the history books.” That led to rampant speculation that project scientists had found evidence for organic materials in the Martian soil. As it turned out, the rover hadn’t found—and still hasn’t found—organic materials, which he noted are difficult to preserve over billions of years. “One thing I discovered back in the fall,” he said at the AAAS press conference, “is that everybody’s expectations are extraordinarily high for things that only under the most extraordinary conditions would ever discover.”

Eventually, Curiosity will begin to head towards the foothills of Mt. Sharp, a goal that remains in place despite the rover’s current detour. “At our team meeting, we did confirm, with very strong consensus, that Mt. Sharp is still the main prize,” Grotzinger said. “It may take us a long time to get there, but we do intend to go there.”