Video: Change of command aboard 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.

Two astronauts ventured outside the International Space Station early Thursday and performed what amounted to hand transplant surgery on the lab’s Canadian-built robot arm, removing a crippled grapple fixture on one end of the space crane and replacing it with an on-board spare.

SpaceX founder Elon Musk said this weekend that the company is about one month away from launching the first Crew Dragon spacecraft on an unpiloted test flight to the International Space Station, a precursor to a demonstration launch with astronauts later this year. He also warned that early test flights of the commercial crew capsule, built under contract to NASA, will be “especially dangerous.”