Sunday's liftoff is planned at 1:25 pm PST from California's Vandenberg Air Force Base, about 160 miles north of Los Angeles.
One is the satellite carrier SpaceX designed specifically for the Iridium NEXT missions, which functions something like an orbital PEZ dispenser, popping out each satellite at the correct time so that they fly in the right place.
Less than 10 minutes after the launch, SpaceX confirmed via Twitter that the rocket's first stage had successfully landed on the company's "Just Read the Instructions" drone ship in the Pacific Ocean.
Friday's launch was the second time SpaceX has launched and landed a reused first-stage. Musk said the updated Falcon 9 "should be capable of an indefinite number of flights with no service".More news: Texas man charged in boating accident that killed 4-year-old
On Friday, a Falcon 9 launched from Cape Canaveral, Florida, carried a communications satellite for Bulgaria into orbit. Iridium previously launched 10 satellites in January, and is now replacing its global satellite network. Each rocket sent its first stage back through the atmosphere to land vertically on a strategically placed barge.
SpaceX landed its first rocket in December 2015, and since then, the company has consistently brought home rocket stages from space. It is SpaceX's rapid-most launch turnaround yet.
"Our operations team is eagerly awaiting this new batch of satellites and is ready to begin the testing and validation process", said Matt Desch, CEO of Iridium and an inductee into Executive Mosaic's Wash100 for 2017.
This also marks the Elon Musk-founded company's second rocket launch and landing in 48 hours, and ninth launch this year.
The launch is the first to feature the use of new grid fins on the rocket's first stage, which steer the stage towards its landing site.
Despite the delays, the car-size satellites being launched today have come a long way since they were first trucked in pairs from Phoenix to Vandenberg.