Officials at NASA's Kennedy Space Center in Florida called off Sunday's planned liftoff due to inclement weather. Cumulus clouds and lightning violated rules for launching Endeavour because of weather near the Shuttle Landing Facility. The runway would be needed in the unlikely event that Endeavour would have to make an emergency landing back at Kennedy.
The STS-127 astronauts left Launch Pad 39A at about 8:35 p.m. EDT to return to crew quarters at Kennedy's Operations & Checkout Building for the night.
Monday's live countdown coverage will begin at 1:30 p.m on NASA Television and NASA's Launch Blog.