A number of media outlets--including this Israeli publication--are mis-characterizing Friday's announcement of a U.S. weapons sale to the Jewish state. According to the website, the Bush Administration apparently changed its mind, and will now allow Israel to acquire 1,000 small-diameter bombs (SDBs) which entered service with the U.S. military last year.
Various media sources have described the weapon (official nomenclature: GBU-39) as a "bunker buster," and in fairness the small diameter bombs have some penetrating power. Thanks to its advanced design, the 250-pound GBU-39 has the same penetrating ability as the one-ton BLU-109. In tests, the small diameter bomb has been able to penetrate up to six feet of concrete, making it potentially useful against aircraft shelters, shallow bunkers and similar-type targets.
Unfortunately, the GBU-39 would have limited utility against deeply-buried, hardened targets like those at Iran's nuclear research facilities. Covered by layers of concrete and earth, some of the research labs at Natanz (and other locations) are at least 30 feet underground, and perhaps as deep as 60 feet.
To get at that type of target, you need a bigger bomb, either a low-yield nuclear device, or a large conventional penetrator like the GBU-28. In tests at Nevada's Tonaph Test Range, the GBU-28 has penetrated up to 100 feet of earth, or 6 meters of solid concrete. Penetrating some of the underground chambers at Natanz would require successive strikes--on the same aim point--by two GBU-28s. Newer variants of the weapon are now fitted with satellite guidance packages, replacing the original laser designation system.
Israel acquired a small number of GBU-28s in 2005, and more were shipped to the IAF at the height of the Lebanon War a year later. But the U.S. has rejected subsequent requests for additional GBU-28s, submitted as part of a military aid request earlier this year. Along with the request for more bunker busters, Washington also rejected a plea for more refueling planes, and an air corridor through Iraq, in the event that Israel decides to attack Iran.
In that sense, approval of the GBU-39 sale was something of a consolation prize. Israeli defense officials view the weapon as the "next generation general-purpose bomb," and not something to destroy Iran's nuclear facilities. Besides, the IAF probably has enough GBU-28s for a limited strike against Tehran, using those weapons to strike the deepest targets, or provide access for other weapons, including the SDB.
But the GBU-39 is effective at other tasks, namely precision strikes in an urban environment. U.S. Air Force jets have used the weapon to great effect in Iraq, taking out high-value terrorist targets with minimal collateral damage. The leaders of Hamas and Hizballah should be very concerned about this acquisition.
During past Israeli campaigns against terror leaders (conducted largely by helicopter gunships), key members of Hamas and Hizballah sought refuge underground. With the GBU-39 mounted on Israeli F-16s and F-15Is, that sanctuary is now in jeopardy.