Space Exploration Technologies (SpaceX) has completed the latest in a series of increasingly powerful test firings of its Falcon 9 booster.
The test of the five Merlin 1C engines, arranged in a cross pattern like the Saturn V moon rocket, is the last step before firing the full complement of nine engines, scheduled for this summer.
At full power the engines generated almost 500,000lb (2,225kN) of force, and consumed 795kg (1,750lb) of fuel and liquid oxygen per second. With all nine engines operating, the Falcon 9 is expected to generate over one million pounds of thrust in vacuum.
Falcon 9 can deliver 11,300kg to a 200km (124 miles) low-Earth orbit compared with the 1,000kg to 185km range of the smaller Falcon 1 variant, which uses one Merlin 1C engine.
The first Falcon 9, contracted to launch a US government payload, will arrive at the SpaceX launch site at Cape Canaveral by the end of 2008, according to vice-president for propulsion Tom Mueller.
The maiden flight is expected late in the first quarter of 2009, some six months later than originally planned. The next flight of SpaceX's smaller Falcon 1 rocket is scheduled for late June or July of 2008.
Last month, SpaceX secured a NASA launch services contract that could be worth up to $1 billion and last from June 2010 to the end of 2012.
Falcon 9's development is, in part, being funded by the NASA Commercial Orbital Space Transportation Services (COTS) programme, which aims to develop alternatives to the Space Shuttle for supplying the International Space Station.