NASA launched its Parker Solar Probe at 3:31 a.m. Eastern on Sunday. The launch in Cape Canaveral, Florida, is NASA's first mission to explore the sun. Powered by a United Launch Alliance Delta IV Heavy rocket, the car-sized probe will travel millions of miles to reach the sun's corona, or outer atmosphere. 3-2-1… and we have liftoff of Parker #SolarProbe atop @ULAlaunch’s #DeltaIV Heavy rocket.