Scientists started mapping the terrain inside Gale Crater even before Curiosity landed, using high-resolution data from cameras in orbit around Mars. Dawn Sumner, a science team member from the University of California at Davis, says she and her colleagues divided the target landing and roving area into 1-mi. squares and are inventorying the features in each using the overhead data.

“We'll use this map to find a path from where we landed to the main target at the base of Mount Sharp, which is south of where we landed,” she says. “So we'll drive on the northwest side of the dunes and go through a break in the dunes, but on the way we're going to have a lot of interesting geology to look at.”

In deciding what to do next, team scientists will try to balance the attraction of a particular feature on the crater floor with the ultimate target, the sedimentary rock on the mountain that will allow Curiosity to sample its way through the planet's history.

The rover's Martian day is divided into battery-powered science and nighttime “sleep” while the radioisotope thermoelectric generator (RTG) recharges the batteries with electricity generated from the heat of decaying plutonium 238. During that time, a group of about 100 scientists and engineers decides what commands to upload to Curiosity for the next day's activity, and then writes, checks and sends as many as 1,000 commands through one of the Mars orbiters or directly to the high-gain antenna on the rover.

“It's a challenging mission to actually do the operations, because we can't joystick the rover because of the time delay and . . . a highly resource-constrained vehicle,” says Andy Mishkin, the JPL engineer who heads the operation. “The amount of power that we're getting from the RTG is basically a little more than you might need to power a 100-watt light bulb.”

The team's commands must meet “hundreds” of flight rules designed to keep one activity from hampering another or damaging hardware, and to make sure the data load that is generated will fit into the available communications links. The exacting, deadline-driven work is complicated by the need to live on Martian time, where a sol is 40 min. longer than a day on Earth—a requirement some team members describe as permanent jet-lag.