The biggest, most sophisticated Mars rover ever built is on its way to the red planet. NASA's Perseverance blasted off from Cape Canaveral, Florida, atop an Atlas V rocket Thursday morning. NASA's Deep Space Network of tracking stations had some difficulty locking onto signals from Perseverance early in the flight. But officials announced with relief a couple of hours later that a solid communication link had been established. NASA Administrator Jim Bridenstine says this is something that they've seen before with other Mars missions. It's the first step in an ambitious project to bring the first Martian rock samples back to Earth to be analyzed for evidence of ancient life. The six-wheeled rover will drill down and collect tiny geological samples that will eventually be retrieved and brought home in about a decade. China and the United Arab Emirates also have spacecraft en route to Mars, after launching last week. They are all due to arrive on Mars in February.