https://qz.com/1286342/spacexs-final-upgrade-to-its-falcon-9-rocket-isnt-quite-final-yet/

SpaceX debuted the last major upgrade of the Falcon 9 rocket in a successful launch on May 10. But it has yet to demonstrate that a critical system in the redesigned rocket is safe enough to carry astronauts to the International Space Station for NASA.

Before the launch, SpaceX CEO and chief designer Elon Musk told reporters he believed that the new Falcon 9 met NASA’s stringent criteria for flying humans into space, but that he “could be mistaken.” Indeed, the vehicle that flew last week—which is designed to fly 10 times in a row with minimal refurbishment—still wasn’t in “crew configuration” because it lacked an upgrade to advanced propellant tanks that worry NASA safety advisors and took the blame for the launchpad explosion of a Falcon 9 in 2016 during fueling.