Live coverage: Rosetta’s final hours

Scientists are bracing for a blitz of discoveries in the last six months of Cassini’s mission at Saturn, when the plutonium-powered robot will repeatedly ram through an unexplored gap in the planet’s famous rings, then make a destructive plunge into the atmosphere in September.

NASA’s Perseverance rover, set for liftoff Thursday on a journey to Mars, posed some unusual challenges for launch crews working with the robot’s plutonium-fueled power generator, but United Launch Alliance’s Atlas 5 rocket is uniquely suited for the job, the company’s CEO says.

A previously-flown Falcon 9 booster blasted off Friday from Vandenberg Air Force Base on California’s Central Coast with 10 new-generation communications satellites for Iridium. Launch occurred 8:27 p.m. EST (5:27 p.m. PST; 0127 GMT).