Live coverage: Three-man crew, including first UAE astronaut, lands in Kazakhstan

Less than a week after winding up a successful spacewalk, outgoing space station commander Jeff Williams, America’s most experienced astronaut, will join two Russian cosmonauts for a fiery descent to Earth Tuesday evening to close out a 172-day mission covering 2,752 orbits and 72.8 million miles since launch last March.

An Atlas 5 booster core and Centaur upper stage have been stacked to launch another commercial freighter with supplies and scientific research gear to the International Space Station next month.

A troublesome liquid oxygen valve on the Space Launch System’s first flight-rated core stage will keep NASA from performing a second test-firing of the rocket’s four main engines this week.