Bunker Busters Bulk Up

None of them are anywhere near as cool as Deep Digger, the bunker-busting bomb that drills its way underground. But various arms of the Defense Department are working on a number of next-generation munitions, designed to take out deeply buried targets, Aviation Week writes.

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Pentagon will be testing the theory next year of whether bigger and heavier is… better for penetrators. The Massive Ordnance Penetrator (MOP) is a behemoth of a bomb, weighing almost 30,000 lb. It is designed to “overwhelm target characterization uncertainties,” according to program officials.

With 5,300 lb. of explosive material, MOP will pack more than 10 times the explosive punch of its BLU-109 [today's bunker-busting workhorse] predecessor… Optimum penetrating distance is classified, but some analysts say it is as much as 200 ft. through reinforced concrete and soil or sand…

MOP will have a blunter nose than its predecessors to keep the weapon intact during penetration… The majority of MOP’s weight is actually carried in the heavy steel casing, according to AFRL [Air Force Research Lab] officials. Once the tests are finished next year, the Pentagon will decide whether to produce the MOP and begin a small stockpile…

About six years ago, AFRL officials developed the Advanced Unitary Penetrator (AUP), which can burrow twice the depth of the BLU-109. The weapon uses denser materials “to pack more mass into a smaller cross-section,” Sands says. It is essentially a massive explosive bullet encased in a shroud that is dimensionally the same as the BLU-109. During penetration, the outer casing peals off, leaving the core to dig and detonate. The technology has been proven but has not been purchased by the Air Force, quite possibly because they need to go deeper still.

Thus, engineers have been experimenting with various steel formulations to improve the likelihood that a penetrator will survive on its path to a target without breaking up midcourse.

Through years of work, AAC and Ellwood National Forge in Irvine, Pa., have developed a very strong steel that is being used on the BLU-122, the Air Force’s newest penetrator, weighing in at 5,000 lb. The team has applied for a patent for the chemical composition and manufacturing process that has produced “Eglin Steel,” a strong blend estimated at one-eighth the cost of experimental metals with similar strength. Prior attempts to formulate similar steel have proved cost prohibitive. The patent for Eglin Steel — a blend of carbon, chromium and tungsten for hardness, and of silicon and nickel for durability — is under final review.

11 Responses to “Bunker Busters Bulk Up”

  1. Allen Thomson says:

    These weapons are cool and it probably doesn’t hurt to have them on the shelf, but there’s another big problem with underground facilities in denied areas: where are their vulnerable parts? Even if the entrances can be spotted, where do the tunnels go from there? A clever, if evil, opponent will presumably include at least a few zigs and zags to increase targeting uncertainties.

  2. I wonder where these MOPs are destined to be used. If my information is correct (and I doubt that it is), Iran and Syria have developed large tunnel networks and bunkers at depths of greater than 70 foot underground and for the purposes of shielding their nuclear projects or WMD.

    I suppose a weapon that could penetrate these type of bunkers is needed in the event the US attacks Iran.

    G.C.

  3. David Hambling says:

    “The technology has been proven but has not been purchased by the Air Force, “

    I think they’re confused, as the AUP/BLU-116 is most definitely in the inventory -

    “One of the newest weapons in the Air Force’s arsenal of hard target penetrating bombs is the AFRL Munitions Directorate-developed Advanced Unitary Penetrator (AUP) shrouded aerial bomb, equipped with the Hard Target Smart Fuze (HTSF). The bomb and its smart fuze were a big hit during Operation Allied Force….”

    http://www.globalsecurity.org/military/systems/munitions/blu-116.htm

    This is approach of just using bigger bombs is very limited and can’t go much further. new technology is needed…

  4. davids says:

    I wonder if the Bomb castings are made up of the same chub armour that the Abram tanks are covered in?

    Are the Bombs covered in Teflon like those so called Cop killer bullets that go thru bullet proof vests?

    What plane carries it? A cargo plane of couse but for opt effect it should be dropped from High altitude like the British tall boys were in WW2. Some 15 thousand feet.

    Depending on the lenght it should fit in the belly of a B-52 and since the weapon is 30 thousand pounds and the old Buff can haul 70 thousand it should be possible.

    A 15 Ton armoured bullet droped from over 30 thousand feet would hit the ground at supersonic speed! And depending on the casting and streght of the bomb itself, smash thru just about anything and dig itself very deep before it goes off.

    Question all those armour piercing 16 inch shells left over from WW 2. Jap’s put fins on some of those shells and used them to great effect against our battleships in pearl harbor.

    A belly load of those same shells [with fins] dropped by a b-52 or B-1’s from 30 to 50 thousand feet might be a great way to smash a large underground area.

    Then again could anyone think of a better way to wreak havok on any deep target with in twenty miles of the Iranian coast than four Old battleships shooting round after round of armour piercing shells into a nuke facility?

  5. CR says:

    Why not a smaller penetrator accelerated by a rocket motor prior to impact? Not as big a bang, certainly, but you would be able to put it on more platforms. Why continue to build bombs that can only be deployed from C-130s?

  6. Siconik says:

    200 ft penetration? I recall reading a paper that concluded a bomb will not pentrate armor more then ~5 projectile lenghts, regardless of shape, weight and velocity.

  7. davids says:

    Good point about the bomb length. B-52 bomb bay is 28 feet long by six foot wide. So you good put in a 27 foot long and 5 foot wide super penertrator bomb. using your formular of five times the projectile length, that gives you a penertration of 135 feet. Not counting rocket boost or special hardened casting or bomb with in a bomb or coated with teflon or some other exotic material. And dropped from over 40 thousand feet.

    I mentioned before if you droped another large bomb first, blasting away soil and cement cover. Then drop your superbomb right down the same hole [[granted it would take a laser target to get that acurate.] It should be able to go even deeper than 200 feet.

    On a side note, On my sugestion of using old 16″ armour piercing shells as Bombs [as the Japs did at pearl harbor] Those shells can punch thru 30 feet of reinforced cement. How much damage this would do or how much damage the shock wave would do to materal below the exploding shell. I do not know!

  8. Siconik says:

    Regarding the pentration depth/length ratio – I got the number from an exelent penetration technology overview right here…

    http://www.defensetech.org/archives/002177.html

    BTW, the magic number is 4 lengths, not 5..

  9. garmr says:

    Question: if engineers can make a bomb hit a very small, precise location (say an exhaust vent), is there any reason you couldn’t make bombs that play “follow-the-leader”? Acting like the teeth of a saw, could a large group of smaller munitions, striking a target in paced succession, dig deeper than one larger bomb?

    Just curious; I’m in no way qualified to have an opinion one way or another, and I’d be glad to know why this wouldn’t work.

  10. bespoke says:

    Quote:
    These weapons are cool and it probably doesn’t hurt to have them on the shelf, but there’s another big problem with underground facilities in denied areas: where are their vulnerable parts? Even if the entrances can be spotted, where do the tunnels go from there? A clever, if evil, opponent will presumably include at least a few zigs and zags to increase targeting uncertainties.
    EndQuote

    Some of the targets these bunker busters are intended for are tunnels deep into mountains, they are bunkers that were built in a huge hole and have been covered up by dirt/concrete/etc. So we know exactly where they are.

    Iran has been using this method for large facilities that are presumed to be used for centrifuges. And when we talk about bunker busters, I would assume the sudden increased interest in them is due to Iran’s activities.

  11. Brian says:

    True, but if you can seal off all the exits, who cares if they stay down there? If communication is cut off, let them suffocate down there.

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