Live coverage: International crew lands in Kazakhstan

With two veteran test pilots at the controls, Virgin Galactic’s SpaceShipTwo rocket plane climbed to the edge of space for the first time Thursday in a major achievement for Richard Branson’s long-sought ambition to begin regular commercial hops with space tourists, and the first piloted flight by a U.S. vehicle above an altitude of 50 miles since the last space shuttle mission in 2011.

The four astronauts preparing to ride SpaceX’s Crew Dragon “Resilience” into orbit climbed aboard their spaceship Thursday at the Kennedy Space Center in a practice run for a launch to the International Space Station planned Saturday night, while mission managers monitored weather and sea conditions in recovery areas across the Atlantic Ocean.

Space station commander Scott Kelly and flight engineer Kjell Lindgren are gearing up for their second spacewalk in nine days Friday, a planned six-and-a-half-hour excursion to reconfigure the ammonia cooling system used by one of the lab’s sets of solar arrays.