Video: Soyuz MS-01 leaves the space station for landing

Preparations for the planned liftoff Thursday of a SpaceX Dragon capsule with a four-person crew to the International Space Station cleared another readiness review Tuesday at NASA’s Kennedy Space Center in Florida, but officials are tracking marginal wind and sea conditions in downrange abort zones in the Atlantic Ocean that could force a launch delay.

The International Space Station received more than 2.5 tons of fresh supplies and experiments Sunday with the arrival of a commercial Cygnus cargo vessel after an automated laser-guided rendezvous.

Boeing’s Starliner crew capsule could take off in October on its first unpiloted test flight to the International Space Station, a company official said recently, while SpaceX finishes up the investigation into the explosion of its Crew Dragon spacecraft during a ground test earlier this year.