A bomb to bust the deepest bunkers

July 13, 2005

DESPITE the intelligence failure that led the Bush administration to believe Iraq had weapons of mass destruction, the Pentagon is pressing ahead with the development of technologies designed to destroy WMDs. Its latest idea is a bomb that can destroy deeply buried WMD storage bunkers by cutting through earth and concrete inside a bubble of air.

Traditional "bunker busters" are streamlined bombs that rely on sheer weight to force their way through soil, rock or concrete. But the new design has a blunt nose that forces the earth ahead of it out to the sides, creating a cavity the bomb can easily slide through, allowing it to reach much deeper buried structures than conventional bunker busters.

New Scientist has learned that the novel warhead is being developed for the Pentagon's Defence Threat Reduction Agency by Lockheed Martin Missiles and Fire Control of Dallas, Texas, in conjunction with the US navy's Surface Warfare Center at Indian Head, Maryland. The DTRA wants the warhead to carry an incendiary payload for incinerating chemical or biological agents.

The design builds on the US navy's work on high-speed torpedoes (New Scientist, 22 July 2000, p 26), which reduce friction around themselves by creating a gas bubble called a supercavity. The Russians have had such a torpedo since the 1990s: called Shkval, it can travel at 360 kilometres per hour.

To create a supercavity that surrounds but doesn't touch the body that created it, the object has to be travelling very fast- at least 180 kilometres an hour if it is in water. And the nose has to be flat to force fluid off the edge with such speed and at such an angle that it avoids hitting the surface of the body. But if this is to be achieved, the result is a supercavitating body with extremely low drag. Instead of being encased in water, it is simply surrounded by water vapour, which is less dense and has less resistance.

But supercavitation may not be limited to liquids. At high enough velocity a blunt-nosed body will force apart any medium it travels through, whether it be water, soil or concrete. If the cavity is large enough, the only surface in contact with the medium will be the blunt tip of the nose.

Lockheed Martin hopes the supercavitating missile will reach 10 times the depth of the current air force record holder, the huge BLU-113 bunker buster, which can break through 7 metres of concrete or 30 metres of earth.

The BLU-113 needs a thick casing to withstand the friction, but a supercavitating bomb suffers less resistance and so could have a thin casing, leaving more space for its explosive or incendiary payload. But some experts are sceptical. "I am still not certain that the term 'cavitation' is correct for a solid," says Nathan Okun, a naval historian. And Robert Nelson of the Union of Concerned Scientists says, "I could believe a penetration factor increase of two but I don't believe a factor of ten." Michael Levi of the Brookings Institution, a Washington DC think tank, sees the need, however. "Increased penetration is more important for chemical and biological agent destroying weapons than other bunker busters because it's essential to get detonation inside the storage area."

Lockheed Martin will soon be putting an end to the speculation: four prototype weapons are due to be tested later this year.

"This article is posted on this site to give advance access to other authorised media who may wish to quote extracts as part of fair dealing with this copyrighted material. Full attribution is required, and if publishing online a link to www.newscientist.com is also required. The story below is the EXACT text used in New Scientist, therefore advance permission is required before any and every reproduction of each article in full. Please contact celia.thomas@rbi.co.uk. Please note that all material is copyright of Reed Business Information Limited and we reserve the right to take such action as we consider appropriate to protect such copyright."



New Scientist

Related Water Articles from Brightsurf:

Transport of water to mars' upper atmosphere dominates planet's water loss to space
Instead of its scarce atmospheric water being confined in Mars' lower atmosphere, a new study finds evidence that water on Mars is directly transported to the upper atmosphere, where it is converted to atomic hydrogen that escapes to space.

Water striders learn from experience how to jump up safely from water surface
Water striders jump upwards from the water surface without breaking it.

'Pregnancy test for water' delivers fast, easy results on water quality
A new platform technology can assess water safety and quality with just a single drop and a few minutes.

Something in the water
Between 2015 and 2016, Brazil suffered from an epidemic outbreak of the Zika virus, whose infections occurred throughout the country states.

Researchers create new tools to monitor water quality, measure water insecurity
A wife-husband team will present both high-tech and low-tech solutions for improving water security at this year's American Association for the Advancement of Science (AAAS) annual meeting in Seattle on Sunday, Feb.

The shape of water: What water molecules look like on the surface of materials
Water is a familiar substance that is present virtually everywhere.

Water, water everywhere -- and it's weirder than you think
Researchers at The University of Tokyo show that liquid water has 2 distinct molecular arrangements: tetrahedral and non-tetrahedral.

What's in your water?
Mixing drinking water with chlorine, the United States' most common method of disinfecting drinking water, creates previously unidentified toxic byproducts, says Carsten Prasse from Johns Hopkins University and his collaborators from the University of California, Berkeley and Switzerland.

How we transport water in our bodies inspires new water filtration method
A multidisciplinary group of engineers and scientists has discovered a new method for water filtration that could have implications for a variety of technologies, such as desalination plants, breathable and protective fabrics, and carbon capture in gas separations.

Source water key to bacterial water safety in remote Northern Australia
In the wet-dry topics of Australia, drinking water in remote communities is often sourced from groundwater bores.

Read More: Water News and Water Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.