By MARCIA DUNN AP Aerospace Writer CAPE CANAVERAL, Fla. (AP) — Two NASA astronauts returned to Earth on Sunday in a dramatic, retro-style splashdown, their capsule parachuting into the Gulf of Mexico to close out an unprecedented test flight by Elon Musk's SpaceX company. It was the first splashdown by U.S. astronauts in 45 years, with the first commercially built and operated spacecraft to carry people to and from orbit. The return clears the way for another SpaceX crew launch as early as next month and possible tourist flights next year. Test pilots Doug Hurley and Bob Behnken rode the […]