Video: Orion flight preps

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.

Fueled segments of the solid rocket boosters that will lift off on the first flight of NASA’s Space Launch System have arrived at the Kennedy Space Center in Florida, but officials will hold off on stacking the boosters until the SLS core stage completes a crucial test-firing later this year.

A Canadian space flier will join three NASA crew members on the first piloted flight of the Space Launch System and Orion spacecraft around the moon, becoming the first non-U.S. astronaut on a lunar voyage, officials announced last week.