Time lapse: Watch the Falcon Heavy placed on pad 39A

SpaceX tested astronaut slidewire escape baskets and fire suppression capabilities Friday at launch pad 39A in Florida, demonstrating systems that would be activated in the event of an emergency before liftoff of a crewed mission.

SpaceX’s next Falcon 9 rocket arrived at launch pad 39A Thursday for a customary hold-down engine firing. Liftoff from Florida’s Space Coast is targeted for Sunday, weather permitting.

Two communications payloads — one for Intelsat and another for Europe’s data relay satellite system — lifted off from French Guiana aboard an Ariane 5 rocket at 1930 GMT (3:30 p.m. EDT) Tuesday.