Live coverage: Ariane 5 blasts off with two Intelsat satellites

SpaceX’s Falcon 9 rocket ignited its nine Merlin main engines for several seconds Thursday at launch pad 39A in Florida, moving the previously-flown booster closer to a scheduled blastoff Monday with a Bulgarian communications satellite.

A week after scrubbing a launch attempt to evaluate an issue with an oxygen sensor, Rocket Lab launched a mission Wednesday to deliver 10 small commercial Earth observation satellites to orbit. Liftoff of the Electron booster from Rocket Lab’s spaceport in New Zealand occurred at 5:21 p.m. EDT (2121 GMT).

Follow the key events of the Falcon 9 rocket’s ascent to orbit with the fifth set of 10 next-generation satellites for Iridium’s voice and data relay fleet.