Liftoff of the Delta 2 rocket with the Mars Climate Orbiter on board

In this story:

• 'Follow the water'
• A probe with eyes -- and ears
• Related stories and sites

(CNN) -- NASA's first Mars-bound spacecraft in two years lifted off flawlessly Friday, beginning a 400-million-mile fact-finding mission that scientists hope will shed light on a puzzling mystery: Where did all the water go?

The Mars Climate Orbiter blasted off from Cape Canaveral, Florida, at 1:45 p.m. EST aboard a Delta 2 rocket. A companion probe, the Mars Polar Lander, is to follow in January.

A camera attached to the first stage of the rocket provides a stunning view of Earth

The 1,300-pound Orbiter, a rectangular spacecraft slightly larger than a refrigerator, is expected to reach Mars in late September.

It will spend two years surveying the Martian atmosphere, tracking the movement of water vapor and dust in the atmosphere, and paving the way for the Mars Lander to touch down in an uncharted polar region next December.

The launch, originally scheduled for Thursday, was postponed so NASA could correct a software glitch.

The Delta 2 separates from its booster rockets  ALSO: Special Section: Exploring Mars

The problem, uncovered during a final prelaunch check, could have led to the spacecraft's batteries being overcharged, spacecraft mission director John McNamee said.

Once settling into a 260-mile-high orbit around Mars, the Climate Orbiter will serve as a weather satellite and communication relay station for the Polar Lander, which will burrow into the ground and analyze the soil.

Ed Weiler, head of the National Aeronautics and Space Administration's space science program, said the goal of both spacecraft is to "follow the water."

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"If you want to look for life, either fossilized life or even extant life on another planet, you have to follow the water," Weiler said.

"We don't think there's any surface water on Mars. But I don't think anybody out there doesn't believe now that water was abundant on Mars at one time, flowed on its surface. The question is where is it now?" Weiler said.

Like the Pathfinder spacecraft, the new probes will send back television images of the Martian terrain. The lander also will release two basketball-sized devices that will crash-land near the planet's South Pole and drill beneath its surface.

Another unique feature of the lander's instrumentation is a microphone -- the first to be put on another planet. NASA will use it to record Martian sounds, such as the rush of wind.

The combined $356 million mission is the first of eight tentatively planned to investigate Earth's nearest neighbor during the next 15 years.

Reuters contributed to this report.