Photos: Atlas 5 rocket aims for International Space Station

Spare parts warehoused in the the United States and Russia will help Boeing finish assembly of a third space station docking port to receive arriving astronauts aboard Boeing’s CST-100 Starliner and SpaceX’s Crew Dragon capsules, replacing a unit lost in a Falcon 9 launch failure last year.

A commercial Dragon cargo capsule will remain at the International Space Station until Saturday, three days later than previously planned due to high sea states observed by the SpaceX recovery team in the spaceship’s splashdown zone in the Pacific Ocean.

Flight controllers at NASA’s mission control center in Houston have completed the robotic swap out of a failed power distribution unit outside the International Space Station, clearing a hurdle ahead of Friday’s predawn launch from Cape Canaveral of a SpaceX supply ship.