Watch live as Elon Musk unveils his vision for missions to Mars

Two communications satellites blasted off Sunday aboard a SpaceX Falcon 9 rocket, kicking off more than a half-year of novel maneuvers in orbit using plasma drive engines to position the spacecraft 22,300 miles above Earth and link the Americas, Europe, Africa and the Middle East.

For the second consecutive day, SpaceX called off a Falcon 9 launch attempt at Cape Canaveral on Thursday evening, this time to complete a software update on the first 60 satellites for the company’s Starlink network to provide high-speed Internet service from orbit.

A Falcon 9 rocket is again standing upright on launch pad 39A at NASA’s Kennedy Space Center in Florida after ground teams lowered the booster Friday to swap out mice heading to the International Space Station for medical experiments.