Watch conditions at Kennedy Space Center during Tropical Storm Isaias

The twin 177-foot-tall solid-fueled boosters for the first flight of NASA’s Space Launch System have been stacked inside the Vehicle Assembly Building at the Kennedy Space Center to await arrival of the rocket’s cryogenic core stage, which is set for a second engine test on a firing stand in Mississippi later this month.

SpaceX’s Falcon 9 rocket is set for liftoff from Cape Canaveral on Monday, heading due east over the Atlantic Ocean to deliver the Koreasat 5A communications satellite into orbit around 36 minutes later.

A SpaceX Falcon 9 rocket and Crew Dragon capsule were raised vertical at launch pad 39A in Florida late Thursday, setting the stage for a launch day dress rehearsal Friday with NASA astronauts Doug Hurley and Bob Behnken — the veteran space fliers assigned to the Crew Dragon’s first piloted mission later this year — before a critical in-flight test of the ship’s emergency escape system Saturday.