Hunt for banned weapons goes ballistic

Forget Hans Blix, the UN and inspectors schooled in the art of uncovering biological, chemical and nuclear agents. There is a quicker way to prove the existence of weapons of mass destruction.

Gather the latest intelligence, decide where the weapons are stashed, and fire a high-velocity projectile at the target. High-tech sensors packed into the projectile will then instantly beam back confirmation that the weapons are there.

It is a high-risk concept that raises many questions, not least its technological feasibility and the political ructions that would follow if such a device were ever built or used. But the US military is taking the idea seriously, New Scientist has learned.

In 2002, in a two-page research paper commissioned by the army, experts from the Institute for Advanced Technology at the University of Texas, Austin, detailed real test results of a prototype projectile designed to verify the existence of WMDs. They say such a device offers a way to inspect for weapons without permission or cooperation.

Hardened concrete

To inspect reinforced concrete bunkers or factory buildings suspected of housing WMDs, the researchers designed a projectile that can penetrate several metres of hardened concrete without damaging its load of sensors.

Its casing is built from AerMet 100, a nickel-cobalt steel with traces of molybdenum and chromium. Heat-treating the casing after it is made gives it an extremely hard surface. The tapering projectile is 230 millimetres long, with a maximum calibre of 45 millimetres, making it wide enough to carry a useful payload.

Five test firings have shown that when the projectile is fired at a velocity of 1200 to 1400 metres per second, it can penetrate more than 1 metre of concrete and emerge relatively intact at around 1000 metres per second. The shell maintains its streamlined shape, losing only 12 per cent of its mass as it passes through the concrete.

Penetrating projectiles can often be sent off course by the shock of impact, and the uneven erosion of the casing as it passes through hard material such as a thick wall. To overcome this, the new projectile has a series of deep groves cut into its casing which act as fins, helping the shell to maintain a straight trajectory as it passes through the concrete.

G forces

The projectile's designers, ballistic expert Mehmet Erengil and director of biological defence Steve Kornguth, both of the Institute for Advanced Technology, and James Valdes of the army's Aberdeen Proving Ground in Maryland, do not address what sensors would be on board, how robust they would be, or whether they could survive impact forces that would be in the region of 100,000g. They were not able to respond to questions put to them by New Scientist.

One solution could be to encapsulate the non-sensing part of any hardware in plastic. Integrated circuits encapsulated in this way have no internal voids or moving parts. Such circuits have already been designed to measure the g forces experienced by high-impact projectiles.

But it is unclear whether chemical, biological and nuclear sensors could be designed this way, and also be capable of sending back their results by telemetry.

Michael Levi of the Brookings Institution in Washington DC points out that such "non-permissive" testing may not have any advantages over existing inspection methods. Anyone hiding weapons could simply dig deeper bunkers to defeat any possible penetrating shell, he says.

Act of war

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Others point out that firing such a weapon could itself be interpreted as an act of war. The high-energy projectiles could kill any occupants of a site being tested, and to sense biological or chemical agents the projectile may have to puncture the agent's containment vessels, releasing them into the atmosphere.

Also, critics could still question the authenticity and relevance of intelligence provided by the shell and released by the government.

But John Pike, director of Washington DC think tank GlobalSecurity.org, and a former technology chief at the Federation of American Scientists, says the design of the shell could work.

"It's enormously elegant," he says. "I would almost say it's surprising no one ever thought of it before. I don't know in the real world whether they'll do that. But it would not be the most wasteful expenditure ever."

David Hambling, with additional reporting by Kurt Kleiner