MOSCOW — A trio of space travelers safely returned to Earth on Thursday after a six-month mission on the International Space Station. The Soyuz MS-16 capsule carrying NASA astronaut Chris Cassidy, and Roscosmos’ Anatoly Ivanishin and Ivan Vagner landed on the steppes of Kazakhstan southeast of the town of Dzhezkazgan at 7:54 a.m. Thursday. While serving as the station’s commander, …