[…] After being scrubbed two hours prior to launch—with Wilmore and Williams already aboard the Starliner—on the evening of 6 May, following observations of a faulty oxygen relief valve on the Atlas V’s Dual-Engine Centaur (DEC) upper stage, the mission was realigned to fly as soon as 6:16 p.m. EDT on the 17th, before slipping again to No Earlier Than (NET) 4:43 p.m. EDT on the 21st, due to a helium leak in Starliner’s service module that was subsequently traced to a flange on a single reaction control thruster. When launch does occur, Wilmore...