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A rover’s life: Getting the answers

A day in the life of a Mars rover: Part 4 -Getting the answers.
Rover planner Eric Baumgartner shows how a software program converts a long list of text commands into an animated simulation of a rover drive on Mars.
Rover planner Eric Baumgartner shows how a software program converts a long list of text commands into an animated simulation of a rover drive on Mars.Jim Seida /
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1 to 2:30 p.m.: While the scientists talk about what Spirit has done, Eric Baumgartner is figuring out what Opportunity will do.

In the rover operations room, off a narrow hallway in Building 264, Baumgartner and 15 other team members — mostly engineers, mostly men — work out every move that Opportunity will make during Sol 47. A software suite known as the Rover Sequencing and Visualization Program, or RSVP, translates the tasks of the day into hundreds of lines of commands for the rover's moving parts.

Baumgartner is one of the Mars missions' eight "rover drivers" — four for Spirit, four for Opportunity. The word "driver" leaves the wrong impression, however: Because the round-trip travel time for radio signals is almost a half-hour, it's impossible for the drivers to steer the rovers in real time.

Baumgartner and his teammates are more like programmers, creating one big chunk of computer code for each day. That code is transmitted to the rover during the Martian morning, and the mission team usually doesn't hear from the rover again until the end of the workday.

"The rover receives its job. ... It does its job completely autonomously, all day long," Baumgartner explains.

Baumgartner is in the process of handing off his work to the rover planner for the next shift, Jeff Biesiadecki, when Squyres saunters in. For a while, he casually visits with the engineers around the room, then he slumps down in chair and gazes once again at a picture of the Martian blueberries displayed on yet another screen.

During the midday break, he and the other scientists have decided to target the triple berry, which is now called Mössberry 2.

"Isn't that something," he says admiringly of the three-lobed berry, which looks like a chemistry-lab model of a water molecule in black and white.

The room's random conversations coalesce into the day's command approval meeting — where the Opportunity team's scientists and engineers do a final reality check on the next day's agenda, including the rover's energy-saving siesta.

Power is a daily concern, especially as the days on Mars get shorter and dust settles on the rovers' solar panels. The afternoon in Pasadena translates into midnight for Opportunity, and the rover is shut down to conserve electricity. On Sol 47, the power requirements will be relatively low because Opportunity won't have to be driven to a new location, and won't need to use its drilling tool.

"It's a good day to recover," mission manager Chris Salvo says.

Baumgartner also has good news: He's decided there's no need to take more pictures of Shoemaker's Patio for navigation purposes, taking some of the pressure off the rover's time schedule. The plan looks good for Sol 47, and Biesiadecki takes over the job of translating the day's tasks into computer code for the rover.

3 p.m. to midnight: Filling out the details
The next few hours are prime time for the engineers rather than the scientists. Biesiadecki puts the command sequences into their final shape. Then the sequences are relayed to the rover via the Deep Space Network's radio antennas and the Mars Odyssey orbiter, at about 11 p.m. PT, or 9 a.m. Opportunity time.

The antennas also beam a wakeup song to the rovers, though that's more for the benefit of the team back on Earth than for the rovers. Because Opportunity will be remaining in position at the Berry Bowl, Sol 47's wakeup music is "No Particular Place to Go" by Chuck Berry. As a bonus, the engineers play Dean Martin's "That's Amore," in honor of the eclipse observations ("When the moon hits your eye...").

Postscript: Getting the answers
Opportunity begins its four hours of scheduled work by taking pictures of the Berry Bowl and doing one of the mini-TES sky stares. But by the time it starts moving its robot arm, it's 11:30 in the morning on Mars, and 1:20 a.m. March 12 in Pasadena.

The rover finishes up the work at the Berry Bowl, performs one of the mini-TES sky stares, then takes pictures of the magnets as well as the rock called Fool's Silver. After recharging with a midday siesta, Opportunity executes another sky stare, watches the eclipse, then goes back to sleep in preparation for an Odyssey communications session in the middle of the Martian night. As Squyres predicted, the sky column observation would have to wait.

It sounds like just another day on Mars, but the work that Opportunity does in early March makes headlines weeks later:

  • The Mössbauer analysis reveals that the mysterious blueberries themselves are the source of the hematite in Meridiani Planum. For the scientists on the Mars team, that makes the berries a key piece of evidence supporting their view that the area where Opportunity landed was once drenched with water.
  • The cross-bedding in the bedrock — documented by Opportunity's microscopic imager, analyzed by the scientists at JPL and later confirmed by the outside experts — turns out to be the best evidence ever found that parts of Mars were once covered with liquid water, perhaps even a salty sea.

Even as the results are being announced, even as the research papers are being written, the rover missions are turning from scientific sprints into marathons. At the height of activity, about 500 people were on the rover mission team. In April, that work force is being drawn down to about 150.

As his shift ends on the afternoon of March 11, Baumgartner marvels at the team he joined back in 1999, when Opportunity was just a gleam in NASA's eye. "There was no hardware built, it was just basically on a pad of paper — ‘this is what we're going to do’ — and the charge was given to the engineering team to go off and build a rover that's going to last on Mars," he recalls.

"I'm blown away by the intelligence of the people around me, it's just a joy to work with them," Baumgartner says. "And I've learned and grown as a result of that as well."

Eventually, Spirit and Opportunity will stop in their tracks, felled by mechanical glitches or the Martian winter. The scientists and engineers who supported them will move on to other missions. But the discoveries made in March will be written into textbooks for decades to come.