The six-wheeled, one-armed rover, nicknamed Curiosity, is on its way to Mars. An unmanned rocket blasted off with the spacecraft.
The trip to the red planet will cover 354 million miles and is expected to land on Mars in August. Once there, the rover will be lowered down to a place called, Gale Crater, which is the size of Connecticut and Rhode Island combined.
The rover weighs a ton and is the size of a car. It's a mobile, nuclear-powered laboratory holding 10 science instruments that will sample soil and rocks and analyze them on the spot. There's a drill as well as a stone-zapping laser machine.
NASA says the rover is the most sophisticated vehicle ever sent to Mars.
"We're going to look for a place on the planet where we think, early in Mars' history, life may have flourished. We're looking in an environment that our orbiters have told us is a place where water was once on the surface," said Richard Zurek, the chief program scientists for Mars at Jet Propulsion Laboratory in Pasadena.
Curiosity will look for evidence that the red planet may once have been - or still is - suitable for microbial life.
Although the $2.5 billion mission is designed for two years, it could be longer if the rover survives the rugged conditions on Mars. Its radioactive power source has a minimum lifetime of 14 years.
JPL engineer Gordy Cucullu said he was extremely proud to share the big moment with his family and colleagues.
"I think I was still just holding my breath until it got high enough and most of the rocket engines have done their job. I'm just excited to finally see it take off," said Cucullu.
The Associated Press contributed to this report.