NASA and aerospace company ATK Aerospace Systems successfully tested 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...