Live coverage: Falcon 9 disintegrates after launch

Four veteran astronauts have been selected to train for launch aboard new commercial crew capsules being built by Boeing and SpaceX that are intended to ferry astronauts to and from the International Space Station starting in 2017, NASA announced Thursday.

SpaceX’s final planned Crew Dragon test flight before astronauts ride the commercial spaceship into orbit is scheduled for Saturday, when an unpiloted crew capsule will fire off the top of a Falcon 9 rocket shortly after launch from the Kennedy Space Center in Florida to test the craft’s in-flight emergency escape capability.

SpaceX has shipped to Cape Canaveral the first Falcon 9 booster equipped with upgrades to haul heavier cargoes to orbit, aiming for a mid-December launch in the space transport company’s first mission since a June rocket failure grounded the Falcon 9.