Nasa has launched the most capable machine ever built to land on Mars.
The near one-tonne rover, tucked inside a capsule, left Florida on an Atlas 5 rocket at 10:02 local time (15:02 GMT).
Nicknamed Curiosity, the rover will take eight and a half months to cross the vast distance to its destination.
Project costed at $2.5bn. It will see initial surface operations lasting two Earth years. On board plutonium generators will deliver heat and electricity for at least 14 years.
If it can land safely next August, the robot will then scour Martian soils and rocks for any signs that current or past environments on the planet could have supported microbial life.
The Atlas flight lasted almost three-quarters of an hour.
By the time the encapsulated rover was ejected on a path to the Red Planet, it was moving at 10km/s (6 miles per second).
Spectacular video taken from the upper-stage of the rocket showed it drifting off into the distance.
Categories: Americas, Science, Science and Technology, United States