Live coverage: Veteran three-man crew docks with space station

Wrapping up 109 days attached to the International Space Station, a Northrop Grumman Cygnus supply ship departed the orbiting research lab Tuesday to begin an extended four-month mission for additional technology demonstrations and smallsat deployments.

Two NASA astronauts and an Italian flight engineer are sheltering in the space station’s Russian segment as mission control analyzes a possible leak of toxic ammonia coolant aboard the complex.

The next three-man crew to launch on a Soyuz rocket — comprising two Russian cosmonauts and a veteran NASA astronaut — is training to have the International Space Station to themselves after their arrival at the orbiting research outpost in April, at least until new U.S. commercial crew ships enter service.