Watch replay of Falcon 9 launch as seen from the press site

SpaceX has delayed the launch of the SES 12 commercial communications satellite from Cape Canaveral until Monday to conduct additional tests on the Falcon 9 rocket’s second stage, officials said Thursday.

Arianespace’s third Ariane 5 launch of the year was set liftoff Friday from Kourou, French Guiana, but an issue with a sensor on the rocket’s first stage liquid hydrogen tank caused officials to scrub the launch attempt. The Ariane 5 is poised to carry three U.S.-built commercial satellites into orbit, while testing a few rocket upgrades, including a modified fairing needed for the launch of the James Webb Space Telescope next year.

SpaceX’s Falcon 9 rocket launched from Cape Canaveral on Monday after a 49-minute weather hold to wait for clouds to thin out overhead. The rocket finally lifted off into an overcast sky with a communications satellite built for Turkmenistan.