Video: Atlas/Cygnus pre-launch news conference

Clad in pressurized spacesuits, two Russian cosmonauts headed outside the International Space Station on Wednesday and hand-released four tiny CubeSats and installed hardware for a German experiment to track animal migration.

Ground teams at the Kennedy Space Center were packing last-minute cargo into a commercial Dragon supply ship Sunday, a day before the automated freighter is set for liftoff on top of a SpaceX Falcon 9 rocket on a two-day trek to the International Space Station.

The Atlas 5 rocket that will send NASA’s Perseverance rover toward Mars next month aced a countdown rehearsal Monday at Cape Canaveral, helping ensure the United Launch Alliance-built rocket is ready for liftoff during the rover’s 23-day launch window.