Video: Delta 2/SMAP pre-launch news conference

Astronauts Christina Koch and Jessica Meir floated back outside the International Space Station Wednesday for history’s second all-female spacewalk, installing two powerful new lithium-ion batteries on the far left end of the lab’s solar power truss.

Opening a new era in American spaceflight, a Falcon 9 rocket streaked into space early Saturday, boosting the company’s first Crew Dragon spacecraft into orbit on an unpiloted test flight, the first launch of a commercially developed capsule intended to carry astronauts to and from the International Space Station.

Picking up where they left off last week, two space station astronauts ventured back outside the outpost Wednesday to continue the replacement of aging batteries in the lab’s solar power system. Two more spacewalks later this month should complete the multi-year project.