#AtlasV, without the Mars 2020 @NASAPersevere payload, rolls to the pad for its Wet Dress Rehearsal. The countdown demonstration will fuel and test the rocket to ensure systems are ready for the upcoming window when Earth can launch spacecraft to Mars. #CountdownToMars pic.twitter.com/Jp1p4tnfbo

— ULA (@ulalaunch) June 20, 2020