Q&A with Keith Gendreau, principal investigator of the first X-ray space communications experiment (members only)

Two spacewalkers attached a new docking port to the International Space Station Friday, clearing the way for U.S. crew ferry ships being built by Boeing and SpaceX to begin test flights to the lab complex next year.

Space station commander Jeff Williams and flight engineer Kate Rubins completed a smooth 6-hour 48-minute spacewalk Thursday, retracting a spare cooling radiator, installing two high-definition TV cameras and inspecting a massive solar array rotation mechanism that has experience subtle vibrations in recent months.

SpaceX aborted a launch attempt Thursday just three seconds before liftoff at the start of the engine ignition sequence, delaying the flight of a Falcon 9 rocket from California with 10 satellites for the U.S. military’s Space Development Agency.