Video: Change of command aboard International Space Station

In a major shakeup at NASA Headquarters, agency Administrator Jim Bridenstine said Wednesday that Bill Gerstenmaier, the widely respected director of human spaceflight, has been replaced in the midst of an ambitious push to meet the Trump administration’s directive to send astronauts back to the moon within five years.

Space station commander Peggy Whitson and astronaut Jack Fischer are set for a two-and-a-half hour spacewalk Tuesday, a quickly-planned excursion to replace a recently installed external computer that failed Saturday.

Just 10 days after three space station fliers returned to Earth — and two days after launch of a station-bound supply ship — a veteran four-flight cosmonaut and an enthusiastic NASA rookie were cleared for launch Thursday to boost the lab’s crew up to five — one less than usual because of cost cutting by the Russian space agency.