largest-ever Mars rover

With the roar of an Atlas 5 engine, NASA on Saturday began its boldest venture yet to another planet — sending the Mars Science Laboratory on an eight-month journey expected to provide more detailed information about whether the Red Planet is, or ever has been, hospitable to life.

After a one-day delay to replace a faulty battery, the launch went off flawlessly at 7:02 a.m. PST, the rocket rising on a column of white smoke into a blue sky mottled with puffy cumulus clouds.

"Whew! That felt so good," said Joy Crisp, a deputy project scientist with NASA's Jet Propulsion Laboratory in La Cañada Flintridge, as the rocket trailed out of sight. "That was spectacular!"

Its payload was the rover Curiosity, the largest and most sophisticated in a series of robotic vehicles that NASA has sent to Mars. Built at JPL, Curiosity is a six-wheeled, one-ton vehicle the size of a compact car that is bristling with an array of sophisticated scientific gadgets.

Its mission, NASA officials have stressed, is not to find life on Mars, but to find out whether life ever could have existed there in the form of microbes, tiny organisms that are abundant on Earth. It also will try to find further evidence to suggest whether astronauts could survive on Mars, part of NASA's long-term plan to send a manned mission there.