Photos: Atlas 5 rocket aims for International Space Station

The 330-foot tall mobile service tower is rolled away from the United Launch Alliance Delta 4-Heavy rocket at Cape Canaveral’s pad 37B on launch day.

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 Heavy rocket rolled out of its hangar and up the ramp to pad 39A at NASA’s Kennedy Space Center in Florida, then was raised vertical at the seaside launch complex early Monday in preparation for a late-night liftoff with two dozen weather observation and technology demonstration satellites.