SpaceX is preparing for its third Falcon Heavy mega-rocket launch, which is set to be undertaken at the Kennedy Space Center in Florida, US.

Carrying 24 satellites into orbit, the Falcon Heavy rocket is set to launch from Cape Canaveral.

SpaceX said that the launch will be its most challenging ever as the satellites are to be released into three different orbits.

It will have four separate upper-stage engine burns, a final propulsive passivation manoeuvre and a total mission duration of more than six hours.

The US Air Force also plans to use side boosters recovered from the Arabsat-6A Falcon Heavy launch site, making it the first reused Falcon Heavy ever flown for the US Air Force.

SpaceX refuelled and refitted the boosters for the upcoming launch, which is part of the US Air Force’s Space Test Program-2.

One of the satellites is a Nasa atomic clock, and others are being operated by the National Oceanic and Atmospheric Administration, Department of Defense research laboratories and several universities.

The STP-2 multi-manifest launch will demonstrate the capabilities of the SpaceX Falcon Heavy launch vehicle and offer critical data supporting certification for future National Security Space Launch missions.

SpaceX designed and manufactured the Falcon Heavy, which is a partially reusable heavy-lift launch vehicle.

It is derived from the Falcon 9 vehicle and features a strengthened Falcon 9 first stage as the centre core with two additional first stages as strap-on boosters.