Live coverage: International crew lands in Kazakhstan

Astronaut Scott Kelly, just back from a record 340-day stay aboard the International Space Station, is leaving NASA at the end of the month, but he said Friday he will continue participating in ongoing medical research to study the effects of long-duration spaceflight.

Bidding their crewmates farewell, a Russian cosmonaut and two NASA astronauts boarded their Soyuz ferry craft, undocked from the International Space Station and fell back to Earth Tuesday, landing safely on the snowy steppe of Kazakhstan to close out a 168-day mission.

A commercial Cygnus supply ship departed the International Space Station on Friday for an extended mission to deploy five nanosatellites and conduct other experiments before re-entering the atmosphere and burning up with more than two tons of trash.