The countdown had less than two minutes to go when it was put on hold today. The attempt had already been halted yesterday to allow more time to chill the super-cooled liquid oxygen propellant that drives the Falcon 9 rocket. The colder the fuel is, the denser it is and the more power the rocket has.

It's unclear why today's launch was also called off. SpaceX said that "teams are reviewing the data and the next available launch date".

The Falcon 9 rocket carrying SES-9 on the launchpad prior to the 6.46pm ET launch window on Friday, 26 February, 2016. The launch was cancelled due to "technical difficulties". (Credit: SpaceX)

Falcon 9 product director John Insprucker, who was commentating on the launch, said during the live webcast that preliminary information indicated that there was a problem with the time left to load the liquid oxygen.

The payload for the mission is the SES-9, a Boeing-built satellite owned by Belgian comms satellite owner and operator SES. The firm tweeted that its satellite "remains healthy".

The sat needs to make it into geostationary transfer orbit, around 26,000 miles above the Earth. After dropping the payload off, SpaceX is hoping to try for another ocean landing of its reusable Falcon 9 rocket.