Apparently one of the rocket’s nine first stage engines shut down prematurely around two minutes, 22 seconds, after lift-off from pad 39A at NASA’s Kennedy Space Centre in Florida, an event visible in a view from a camera streaming live video from the Falcon 9 as it climbed into the upper atmosphere.

Elon Musk, SpaceX’s founder and CEO, confirmed in a tweet that the Falcon 9 experienced an “early engine shutdown on ascent, but it didn’t affect orbit insertion”.

The rocket’s other Merlin engines fired a little longer to compensate for the loss of thrust. The rest of the Falcon 9’s climb into orbit appeared to go according to plan, and the upper stage deployed the 60 Starlink satellites into orbit around 15 minutes after liftoff.

There are nine kerosene-fueled Merlin 1D engines on the Falcon 9’s first stage, each generating 190,000 pounds of thrust at sea level when firing at full power. The Falcon 9 is designed to persevere through a booster engine failure and still deliver its payload to orbit.

It is the second time a Merlin engine has prematurely shut down on a Falcon 9 flight – the last time was in 2012 in that case the Falcon 9 was still able to deliver the Dragon spacecraft into orbit, but the failure resulted in the loss of an Orbcomm data relay satellite riding as a secondary payload.