SpaceX has successfully test-fired its Falcon Heavy rocket in anticipation of the full launch, expected to take place ‘in a week or so’, according to founder and CEO Elon Musk.

The ‘static fire’ involved the ignition of all 27 of the rocket’s Merlin engines, albeit while it remained clamped to the ground at the Kennedy Space Centre in Florida.

The engines were only fired for 12 seconds, but are capable of generating nearly 23,000 kilonewtons, equivalent to over 5 million pounds, of thrust, more than double that of the world’s most powerful rocket, the Delta IV Heavy, operated by American competitor United Launch Alliance (ULA).

The SpaceX vessel consists of three first stage boosters, also known as ‘cores’, each boasting nine engines and based on the design of the company’s earlier Falcon 9 craft, a single second stage engine, and what SpaceX calls a ‘fairing protector’ at the top of the craft to carry the payload. The cores fire in sequence, with the outer cores operating first, and the central core only firing when the outer cores have throttled down. This means that the craft will continue to move even if there is ‘more than one unplanned engine shutdown’, according to SpaceX’s website.

The Falcon Heavy is capable of carrying a payload of up to 64 tonnes, equivalent to a Boeing 737 jetliner loaded with passengers, crew, fuel and luggage. This total is also significantly greater than the 29 tonnes that can be carried by the ULA craft.

The first payload is to be a red roadster belonging to Musk himself. He tweeted: “Falcon Heavy hold-down firing this morning was good. Generated quite a thunderhead of steam. Launching in a week or so.”

SpaceX has four projects lined up for the Falcon Heavy, three of which are routine satellite deliveries; the other is the sale of a Falcon Heavy craft to the US Air Force for use in its Space Test Program, despite the vessel not being fully tested. The latter project, named the STP-2, will involve the Lightsail 2, a smaller craft operated by the Planetary Society, being carried into orbit as the Falcon Heavy’s payload.

The successful test comes following the unknown fate of project Zuma, which launched on 8 January; a satellite built by Northrop Grumman was launched atop a SpaceX Falcon 9 engine as part of a covert government operation, but it is unknown if the satellite ever reached orbit.