Watch the Falcon 9 test fire its engines ahead of Starlink launch (members only)

SpaceX’s next Falcon 9 rocket launch, using a previously-flown first stage booster, took a step closer to liftoff Thursday with a countdown rehearsal culminating in ignition of the launcher’s nine Merlin main engines in a hold-down firing at pad 39A at NASA’s Kennedy Space Center in Florida.

Follow the key events of the Falcon 9 rocket’s ascent to orbit with five more Iridium Next communications satellite and the U.S.-German GRACE-Follow On climate research mission.

Packed with food, hardware and experiments in biology, Earth science and space technology, a Falcon 9 rocket and Dragon supply ship lifted off Monday from Cape Canaveral destined for the International Space Station.