CAPE CANAVERAL, Fla.—Four astronauts in orbit since spring headed back to Earth on Monday, aiming for a late night splashdown off the Florida coast. The undocking of their SpaceX capsule from the International Space Station also paved the way for a launch of their four replacements as early as Wednesday night. The newcomers were scheduled to launch first, but NASA switched the order because of bad weather, and an astronaut’s undisclosed medical condition. The welcoming duties will now fall to the lone American and two Russians left behind at the space station. NASA astronauts Shane Kimbrough and Megan McArthur, Japan’s Akihiko Hoshide, and France’s Thomas Pesquet should have been back Monday morning, but high wind in the recovery zone delayed their homecoming. Their splashdown was planned for the Gulf of Mexico off Pensacola. “One more night with this magical view. Who could complain? I’ll miss our spaceship!” Pesquet tweeted alongside …