CAPE CANAVERAL, Fla. — Three rich businessmen returned from the International Space Station with their astronaut escort Monday, wrapping up a pricey trip that marked NASA’s debut as a B&B host. Flying back in a SpaceX capsule, they splashed down in the Atlantic off the Florida coast to close out a 17-day tour that cost them $55 million apiece. The trip was supposed to last a little over a week, but dicey weather kept the visitors in orbit almost twice as long as intended. “Welcome back to planet Earth,” radioed SpaceX Mission Control from Southern California.