Video: Soyuz MS-01 leaves the space station for landing

With three space station fliers heading home Sunday after a 168-day mission, three fresh crew members made final preparations for launch three days later to boost the lab’s crew back to six in a rapid-fire rotation that will prevent any major interruption of research activity.

A SpaceX-owned Dragon cargo craft left the International Space Station on Friday and flew back to Earth for a parachute-assisted splashdown in the Pacific Ocean with a dozen mice and more than 3,000 pounds of experiment specimens and space hardware.

A Russian military spacecraft with a high-resolution digital mapping camera is in orbit Thursday after a successful ascent aboard a Soyuz rocket.