CAPE CANAVERAL, Fla. -- The spectacular nighttime explosion of a Delta III rocket on Wednesday was caused by a steering system failure, officials said Friday.
The inaugural flight of Boeing's new rocket ended 71 seconds after liftoff when the control system in three solid propellant boosters ran out of hydraulic fluid.
"It's like on your car when you don't have power steering," said Clarence Quan, Boeing's lead investigator.
The Delta III uses a steering system derived from, but more complex, than that of the less powerful Delta II.
"Clearly, we missed something," said Quan. Both mechanical and electronic components could be responsible for the rocket wobbling out of control, he said.
The rocket then deviated from its flight path, broke up and finally exploded.
It is still unclear why the boosters prematurely used up all the hydraulic fluid.
The mission was valued at $225 million.
Officials said an object that continued flying after the explosion was the Galaxy communications satellite the Delta was supposed to deliver into space.
The satellite crashed in a fireball into the Atlantic Ocean 15 miles offshore.
Boeing said that as a precaution, it will delay the scheduled Sept. 1 launch of a Delta II from Vandenberg Air Force Base, Calif., by a few days.
The rocket is to carry five Iridium satellites into orbit.