DM-2 (Demonstration Motor 2) NASA and aero space company

NASA and aero space company ATK Aerospace Systems successfully tested on Tuesday the most powerful solid-fuel rocket engine ever, even though its future in the space program remains in doubt.

A huge roar and massive flames accompanied the two-minute "static" or non-flight test of the five-segment DM-2 (Demonstration Motor 2) rocket booster in the western desert state of Utah.

The DM-2 was designed as the first stage of the Ares I rocket to provide the lift-off thrust for the next generation of Orion spacecraft, which NASA hoped would return astronauts to the moon by 2020.

US President Barack Obama has said he plans to cancel the Constellation program in which the boosters would have been used, throwing the fate of the next-generation engine into question.

The second test of the DM-2 was aimed at seeing if it could work at lower temperatures and verify the performance of new design materials.

The solid rocket boosters are an upgrade in design over ones used to propel NASA's shuttle fleet into space and are the largest and most powerful ever designed for flight.

Once the shuttle program ends early next year, the United States will rely on Russia's Soyuz rockets to carry its astronauts to the International Space Station until a commercial US launcher can be developed, scheduled for 2015.

The second test of the DM-2, aided by more than 760 on-board measurement devices, showed the motor's performance had met all expectations.

"For every few degrees the temperature rises, solid propellant burns slightly faster," said Alex Priskos, first stage manager for Ares Projects at NASA's Marshall Space Flight Center in Huntsville, Alabama.

"Only through robust ground testing can we understand how material and motor performance is impacted by different operating conditions."

Seeking to cut the massive US budget deficit, Obama's administration has proposed scrapping the costly and over budget Constellation rocket program.

Instead, NASA would concentrate on research and development that could, over a longer time-frame, eventually see astronauts travel outside low Earth orbit and even aim for Mars.

The US space agency would also be encouraged to develop operations with commercial partners to fly astronauts to the space station.