NASA's most elaborate life-hunting Mars rover has rocketed away from Cape Canaveral, Florida. The rover, named Perseverance, rode a mighty Atlas V rocket into the morning sky Thursday in the world's third and final Mars launch of the summer. It follows China's rover-orbiter combo and a United Arab Emirates orbiter, both launched last week. Each spacecraft will take about seven months to reach Mars after traveling 300 million miles. Perseverance will drill down and scrounge for evidence of past microscopic life in an ancient lakebed at Mars, and gather the most promising rock samples for future pickup. NASA is teaming up with the European Space Agency to return the samples to Earth around 2031. This unprecedented effort will involve multiple launches and spacecraft - and cost more than $8 billion. The U.S. remains the only country to land successfully at Mars. If all goes well next February, Perseverance will become the ninth U.S. spacecraft to operate on the Martian surface.