GBU-28 Bunker Buster

Photo courtesy Air Force

There are thousands of military amenities around the world that defy typical attack. Caves in Afghanistan burrow into mountainsides, and immense concrete bunkers lie buried deep within the sand in Iraq. These hardened facilities home command centers, ammunition depots and research labs which can be both of strategic importance or important to waging battle. Because they are underground, they are laborious to seek out and extremely tough to strike.

The U.S. army has developed a number of totally different weapons to attack these underground fortresses. Known as bunker busters, these bombs penetrate deep into the earth or proper by way of a dozen feet of strengthened concrete earlier than exploding. These bombs have made it possible to succeed in. Destroy services that would have been impossible to assault in any other case.

Conventional Bunker Busters

Throughout the 1991 Gulf war, allied forces knew of several underground military bunkers in Iraq that have been so well strengthened and so deeply buried that they were out of attain of present munitions. The U.S. Air Force began an intense research and improvement course of to create a brand new bunker-busting bomb to reach and destroy these bunkers. In just a few weeks, a prototype was created. This new bomb had the following options:

Its casing consists of an approximately 16-foot (5-meter) section of artillery barrel that is 14.5 inches (37 cm) in diameter. Artillery barrels are product of extremely sturdy hardened steel in order that they can withstand the repeated blasts of artillery shells when they’re fired.

Inside this steel casing is nearly 650 pounds (295 kg) of tritonal explosive. Tritonal is a mixture of TNT (eighty percent). Aluminum powder (20 percent). The aluminum improves the brisance of the TNT — the pace at which the explosive develops its most stress. The addition of aluminum makes tritonal about 18 p.c more highly effective than TNT alone.

Attached to the front of the barrel is a laser-guidance assembly. Either a spotter on the ground or in the bomber illuminates the target with a laser, and the bomb houses in on the illuminated spot. The steering meeting steers the bomb with fins which might be a part of the assembly.

Attached to the top of the barrel are stationary fins that provide stability during flight.

The completed bomb, recognized as the GBU-28 or the BLU-113, is 19 feet (5.8 meters) long, 14.5 inches (36.Eight cm) in diameter and weighs 4,400 pounds (1,996 kg). You’ve got a particularly robust tube that could be very narrow for its weight and extremely heavy.

The bomb is dropped from an airplane so that this tube develops an excessive amount of velocity, and subsequently kinetic energy, because it falls.

Photos courtesy U.S. Department of Defense

When the bomb hits the earth, it’s like a large nail shot from a nail gun. In checks, the GBU-28 has penetrated one hundred ft (30.5 meters) of earth or 20 feet (6 meters) of concrete.

In a typical mission, intelligence sources or aerial/satellite photos reveal the placement of the bunker. A GBU-28 is loaded into a B2 Stealth bomber, an F-111 or similar aircraft.

An F-15E Strike Eagle pilot and a weapons system officer inspect a GBU-28 laser-guided bomb.

The bomber flies near the target, the goal is illuminated and the bomb is dropped.

Air-to-air view of GBU-28 hard target bomb on an F-15E Eagle

Photo courtesy U.S. Department of Defense

The GBU-28 has up to now been fitted with a delay fuze (FMU-143) in order that it explodes after penetration reasonably than on impact. There has also been a good bit of analysis into smart fuzes that, using a microprocessor and an accelerometer, can really detect what is going on throughout penetration and explode at exactly the fitting time. These fuses are known as hard goal good fuzes (HTSF). See GlobalSecurity.org: HTSF for details.

The GBU-27/GBU-24 (aka BLU-109) is almost similar to the GBU-28, besides that it weighs only 2,000 pounds (900 kg). It is less expensive to manufacture, and a bomber can carry more of them on every mission. More weight gives the bomb extra kinetic power when it hits the goal.

They could make the weapon smaller in diameter. The smaller cross-sectional area signifies that the bomb has to move much less materials (earth or concrete) “out of the way” because it penetrates.

They could make the bomb sooner to extend its kinetic power. The one sensible solution to do that is so as to add some sort of large rocket engine that fires proper earlier than impression.

One way to make a bunker buster heavier while sustaining a narrow cross-sectional area is to make use of a metal that is heavier than steel. Lead is heavier, but it is so tender that it’s ineffective in a penetrator — lead would deform or titanium alloy disintegrate when the bomb hits the target. DU is the material of choice for penetrating weapons because of these properties. For instance, the M829 is an armor-piercing “dart” fired from the cannon of an M1 tank. These 10-pound (4.5-kg) darts are 2 ft (61 cm) lengthy, approximately 1 inch (2.5 cm) in diameter and leave the barrel of the tank’s cannon traveling at over 1 mile (1.6 km) per second. The dart has a lot kinetic energy. Is so strong that it is ready to pierce the strongest armor plating.

Depleted uranium is a by-product of the nuclear energy trade. Natural uranium from a mine comprises two isotopes: U-235 and U-238. The U-235 is what is required to produce nuclear power (see How Nuclear Power Plants Work for particulars), so the uranium is refined to extract the U-235 and create “enriched uranium.” The U-238 that is left over is called “depleted uranium.”

U-238 is a radioactive metal that produces alpha and beta particles. In its solid kind, it isn’t particularly harmful as a result of its half-life is 4.5 billion years, meaning that the atomic decay may be very sluggish. Depleted uranium is used, for example, in boats and airplanes as ballast. The three properties that make depleted uranium helpful in penetrating weapons are its:

Density – Depleted uranium is 1.7 occasions heavier than lead, and 2.Four instances heavier than steel.

Hardness – In the event you take a look at an internet site like WebElements.com, you may see that the Brinell hardness of U-238 is 2,400, which is just shy of tungsten at 2,570. Iron is 490. Depleted uranium alloyed with a small quantity of titanium rod is even more durable.

Incendiary properties – Depleted uranium burns. It’s one thing like magnesium on this regard. In the event you heat uranium up in an oxygen setting (regular air), it can ignite and burn with an especially intense flame. Once inside the target, burning uranium is one other a part of the bomb’s destructive energy.

These three properties make depleted uranium an obvious alternative when creating superior bunker-busting bombs. With depleted uranium, it is possible to create extraordinarily heavy, strong and slender bombs that have great penetrating drive.

But there are problems with utilizing depleted uranium. The United States makes use of tons on depleted uranium on the battlefield. At the end of the conflict, this leaves tons of radioactive material within the atmosphere. For instance, Time journal: Balkan Dust Storm reviews:

NATO aircraft rained more than 30,000 DU shells on Kosovo through the 11-week air campaign… About 10 tons of the debris had been scattered across Kosovo.

Perhaps 300 tons of DU weapons had been utilized in the primary Gulf warfare. When it burns, DU varieties a uranium-oxide smoke that is well inhaled and that settles on the bottom miles from the point of use. Once inhaled or ingested, depleted-uranium smoke can do quite a lot of injury to the human physique because of its radioactivity. See How Nuclear Radiation Works for particulars. The thought is to marry a small nuclear bomb with a penetrating bomb casing to create a weapon that can penetrate deep into the ground and then explode with nuclear drive. The B61-11, available since 1997, is the present state-of-the-art in the area of nuclear bunker busters.

From a sensible standpoint, the benefit of a small nuclear bomb is that it may pack so much explosive power into such a small space. (See How Nuclear Bombs Work for particulars.) The B61-eleven can carry a nuclear cost with wherever between a 1-kiloton (1,000 tons of TNT) and a 300-kiloton yield. For comparability, the bomb used on Hiroshima had a yield of approximately 15 kilotons. The shock wave from such an intense underground explosion would cause harm deep within the earth. Would presumably destroy even probably the most nicely-fortified bunker.

From an environmental and diplomatic standpoint, nevertheless, using the B61-eleven raises various issues. There isn’t a approach for any known penetrating bomb to bury itself deeply sufficient to comprise a nuclear blast. Which means that the B61-11 would leave an immense crater. Eject a huge amount of radioactive fallout into the air. Diplomatically, the B61-11 is problematic because it violates the international need to eradicate using nuclear weapons. See FAS.org: Low-Yield Earth-Penetrating Nuclear Weapons for details.

For more data on the GBU-28, the B61-11 and depleted uranium, try the links on the next web page.org: Guided Bomb Unit-28 (GBU-28)

GlobalSecurity.org: Guided Bomb Unit-28 (GBU-28)

South Florida Sun-Sentinel: Attacking bunkers – good animation

csmonitor.com: New push for bunker-buster nuke

CNN.com: U.S. If you have any thoughts about in which and how to use titanium bar alloy (https://peatix.com/user/11088635), you can speak to us at our website. Air Force seeks deeper penetrating “bunker-buster” weapon