A NASA spacecraft carrying a Mars rover was in “excellent health” Saturday more than two hours after it began its eight-and-a-half-month journey.

The mission began at Cape Canaveral, Fla., with a clean liftoff. The spacecraft sent a signal after separation from the rocket, NASA said.

Upon arrival after its 354 million-mile trip, the rover will collect rocks and soil on the Red Planet to see if there are signs of life — in the form of organic material.

The rover, dubbed “Curiosity,” is scheduled to land Aug. 6.

It will be lowered by tether to Gale Crater. If water ever existed on Mars, scientists say, it would have been in the crater.

“Curiosity” will help determine whether an area on the planet “has ever been a potential habitat for Martian life,” NASA said.

“This sets up the future of finally answering that age-old question: Does life exist on other planets?” said deputy project manager Ashwin Vasavada.

The mission will last one Martian year, which is 687 Earth days, NASA says.

The rover, about the size of a compact car, weighs 1 ton and has a 7-foot arm that will be used to collect material.

“On Mars, if life exists as single cell-organisms, or if it ever existed, we believe it will be under the ground, or inside rocks,” said mission chief engineer Rob Manning.

The project costs $2.5 billion.