Live coverage: Atlas 5 countdown and launch journal

Mission managers are weighing a motley mix of weather models, safety criteria and astronaut workload considerations as they decide when SpaceX’s Crew Dragon spacecraft might have the best chance to launch from the Kennedy Space Center.

NASA’s Perseverance rover has recorded the crunching, rattling sound of its six metallic wheels rolling across Mars.

A Northrop Grumman Antares rocket powered off its launch pad at Wallops Island, Virginia, on Feb. 20 with a Cygnus supply ship heading for the International Space Station.