Video: Change of command aboard International Space Station

NASA is sure enough that Boeing and SpaceX can safely launch astronauts to the International Space Station by early 2019 to hold off paying Russia to keep flying U.S. crews to the research complex, and one official says a deadline to order parts for new Russian Soyuz crew capsules may have already passed.

An Antares rocket is being prepared for launch for the first time in two years after emerging from the Horizontal Integration Facility at Wallops Island, Virginia, on Thursday evening for a one-mile trip to the launch pad.

A SpaceX Dragon supply ship arrived at the International Space Station Saturday carrying a new docking mechanism, a spacesuit for future spacewalks, and a 3D bioprinter to test the feasibility of manufacturing human tissue in microgravity.