In the second launch explosion in two weeks, Boeing's newest rocket vanished in bright orange flashes a minute into its inaugural flight.

The Delta III rocket blew up 10 miles above the Atlantic Ocean on Wednesday night, destroying the communication satellite on board. The wreckage slammed into the sea; part of it exploded upon impact, creating a brown mushroom cloud.It was a $225 million disaster.

"Disappointment - it's like being punched in the belly," said Brig. Gen. F. Randall Starbuck of the Cape Canaveral Air Station.

On Aug. 12, a much bigger and more powerful Air Force Titan rocket exploded 40 seconds after liftoff, destroying the spy satellite on board at a cost of more than $1 billion.

No one was injured in either accident.

The Delta III blasted off a half-hour late because of high wind and faulty signals with the rocket's safety system. The first sign of trouble came 55 seconds into the flight when the rocket began to lose control.

Moments before six of the strap-on boosters were supposed to peel away - about 70 seconds into the flight - the 12-story rocket tilted, broke apart and erupted in a fireball.

Five seconds later, the Air Force sent destruct signals to break the rocket into smaller pieces for safety. The debris landed about 10 miles offshore.

Outside the launch site gates, hundreds of spectators cheered what they thought to be the separation of the boosters, then grew silent when they realized something had gone wrong.

The boosters are made in Utah by Alliant Techsystems.

Boeing officials said an investigation began immediately. The last time a Boeing rocket exploded was in January 1997, 13 seconds after liftoff, because of a cracked booster; that one was a Delta II. The Delta III is the largest and mightiest model in the Delta rocket line.