Live coverage: Space station crew safely returns to Earth

The launch of a NASA ionospheric research satellite off Florida’s east coast is targeted for Oct. 9 after persistent technical problems with its air-dropped Pegasus rocket stymied two launch opportunities last year.

Two American astronauts and one Russian cosmonaut boarded their Soyuz MS-06 landing craft for a homecoming Tuesday night, U.S. time, concluding 168 days in orbit. The trio undocked from the International Space Station at 5:08 p.m. EST (2208 GMT), and landed on the snowy steppe of Kazakhstan at 9:31 p.m. EST (0231 GMT Wednesday).

NASA is sending into orbit Monday night a spacecraft to test a safer type of rocket fuel, an ultra-precise atomic clock that could change the way missions navigate in deep space, and an experiment to examine the resiliency of electronics to radiation.