Bunker buster is on fast track

Massive bomb for fortified sites like Iran's, N. Korea's

WASHINGTON - The Pentagon is speeding up delivery of a colossal bomb designed to destroy hidden weapons bunkers buried underground and shielded by 10,000 pounds of reinforced concrete.

Call it Plan B for dealing with Iran, which recently revealed a long-suspected nuclear site deep inside a mountain near the holy city of Qom.

The 15-ton behemoth - called the "massive ordnance penetrator," or MOP - will be the largest non-nuclear bomb in the U.S. arsenal and will carry 5,300 pounds of explosives.

The bomb is about 10 times more powerful than the weapon it is designed to replace.

The Pentagon has awarded a nearly $52 million contract to speed up placement of the bomb aboard the B-2 Stealth bomber, and officials say the bomb could be fielded as soon as next summer. Guided by GPS navigation, a pair of MOP bombs can be carried aboard an Air Force B-2 bomber; Northrop Grumman started integrating the MOP with the B-2 in July 2007.

Pentagon officials acknowledge that the new bomb is intended to blow up fortified sites like those used by Iran and North Korea for their nuclear programs, but they deny there is a specific target in mind.

"I don't think anybody can divine potential targets," Pentagon press secretary Geoff Morrell said. "This is just a capability that we think is necessary given the world we live in."

Boeing has been testing the bomb for several years: A static tunnel lethality test was completed by the company on March 14, 2007, at a weapons testing tunnel complex maintained by the Defense Threat Reduction Agency at the White Sands Missile Range in New Mexico.