Photos: More shots of Delta 4 liftoff

Plans to launch a Navy communications satellite aboard an Atlas 5 rocket early Monday have been interrupted by Tropical Storm Erika, an unpredictable cyclone with its sights on Florida.

Two U.S.-built commercial communications satellites moved to their last stop on Earth on Tuesday, when an Ariane 5 rocket rolled out to a launch pad at the edge of the Amazon jungle on the eve of liftoff.

A senior NASA official said Tuesday that the Space Launch System, a huge heavy-lift rocket years behind schedule, could launch astronauts on a moon landing mission in 2024 on just its third flight to meet a goal announced last month by Vice President Mike Pence, while commercial companies will be entrusted with more responsibility to develop a lunar lander and a modest mini-space station, or Gateway, in lunar orbit.