Video: Change of command aboard International Space Station

Astronauts Terry Virts and space station commander Barry “Butch” Wilmore ventured back outside Sunday for their third spacewalk in eight days to complete initial preparations for upcoming dockings by commercially developed Boeing and SpaceX crew ferry ships.

SpaceX sent a cargo capsule with nearly 5,500 pounds of experiments and supplies on a three-day trip to the International Space Station on Sunday, firing the automated spaceship through low-hanging clouds and into orbit from the same launch pad where Apollo astronauts began voyages to the moon.

NASA has a builder to construct a five-ton spacecraft to catch up with the aging Landsat 7 Earth observation satellite and refuel it in 2020, employing robotic tools mastered in years of rehearsals on the International Space Station.