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A day in the life of a Mars rover

NASA’s team navigates a zigzag course to discovery. Go behind the scenes in this interactive special report from

More than $3 million a day: That's how much NASA is paying to have the Spirit and Opportunity rovers on Mars, calculated simply by dividing the $835 million budget for the rovers' mission by the projected 240 days of operation.

By that measure, each day of the rovers' working season is valued more highly than each day of the regular season for the world's highest-paid baseball player.

Of course, Spirit and Opportunity don't get a dime of those millions: Instead, most of the money has gone out over the past five years to the people who put the rovers on Mars, are keeping them going and are harvesting the precious scientific return from millions of miles away.

So a day in the life of the rover is actually a day in the lives of those scientists and engineers, mostly working at NASA's Jet Propulsion Laboratory here in Pasadena. The team does most of its work while the rover is idle, and the rover does its most of its work without real-time supervision.

Is the payoff worth $3 million a day? You could make a case for it if you eavesdropped on the mission operations of March 11, 2004, as we did. Here's an inside look at how that multimillion-dollar day on Mars unfolded on Earth:

Midnight to 7 a.m. PT: Setting the scene
The rover mission is a round-the-clock operation, with the two rovers operating almost exactly a half Martian day off synch, and NASA's Deep Space Network gathering data from radio antennas in California, Spain and Australia. But it all comes together at JPL's Building 264.

The building looks more like a ’70s-vintage courthouse or college hall than the nerve center for the Mars Exploration Rovers. The college analogy is particularly apt: The Jet Propulsion Laboratory's campus is nestled against the Angeles National Forest, and deer occasionally stroll through the tree-lined square in front of Building 264, not far from the guard-patrolled gates.

Inside Building 264, the focus is Mars, not Mother Nature. On this day, Opportunity's prime time comes during the middle of the night in Pasadena. The results from the 46th Martian day of the rover's operations — known as Sol 46 — are transmitted back to Earth via the orbiting Mars Odyssey spacecraft. As team members meet for the Science Downlink Assessment, the sun hasn't yet risen in California, and it hasn't quite set on Opportunity.

Opportunity's current focus is the mysterious BB-sized "blueberries" that litter the ground and the rocks around Eagle Crater, its landing site in Meridiani Planum. Even as scientists pore over the data already downlinked to Earth, the rover stretches out its robotic arm on Mars and uses its alpha proton X-ray spectrometer, or APXS, to analyze a concentration of the spherules in a rocky depression nicknamed the "Berry Bowl."

7 to 8:30 a.m.: Sharing the science ... and keeping a secret
While Opportunity is winding up its workday, Spirit is sitting on the rim of a crater half a world away, awaiting its wakeup call. Back on Earth, Spirit will be the star of the weekly news briefing at JPL, so three hours in advance, scientists and mission planners gather in a conference room in Building 264 to hash over what they'll say — and what they won't say.

The six panelists will talk about Spirit's arrival at Bonneville crater the night before, after almost a month of zigzagging travel. They'll release pictures of Earth as seen from Mars, solar eclipses and sky streaks, all courtesy of Spirit. They'll also provide an update on Opportunity's activities — but the biggest news from Meridiani Planum will have to remain a secret.

For weeks, Opportunity has been taking close-up pictures of the bedrock in Eagle Crater, Sediment experts on the science team suspect that the fine pattern of layering, known as "cross-bedding," indicates that flowing water affected how the rock was formed. Before they announce that major scientific finding, however, the team leaders want to have their view confirmed by six outside experts.

As the panelists for the weekly briefing go over the day's images, Cornell University astronomer Steve Squyres, the principal investigator for the rover missions, pops in to congratulate them — and reminds them not to mention the cross-bedding.

The early-morning huddle morphs into a bigger gathering of about 25 scientists and engineers just next door: the daily meeting of the Science Operations Working Group.