Clearing minefields is terrifying enough, but mines that move around will make it virtually impossible
Landmines that hop around to foil the crews that clear minefields are under development in the US. The so-called "self-healing" minefield can detect when a path is being cleared through it and instruct the remaining mines to plug any gaps.
Ironically, the technology is being developed because the US plans to sign up to the Ottawa Convention, which bans antipersonnel landmines.
Anti-tank minefields are usually protected by small antipersonnel mines. These are meant to hinder soldiers who try to clear a route through the minefield. But antipersonnel mines are banned under the Ottawa Convention-already signed by more than 135 countries-which the US will sign up to in 2006. To make future anti-tank minefields tougher to cross without antipersonnel mines, the US Defense Advanced Research Projects Agency (DARPA) has committed $13 million to the development of "intelligent" minefields.
At Sandia National Laboratory in Albuquerque, New Mexico, Rush Robinett and his colleagues are developing robotic anti-tank mines that can plug gaps in a minefield by hopping about. "I was catching grasshoppers to go trout fishing when I noticed that they jump around in a random fashion, hit the ground in an arbitrary orientation, then right themselves and jump again," he says. "I said to myself: 'I can build a robot that can do that.'"
Hopping has a distinct advantage over more conventional means of getting about, says Robinett. "Robots with wheels and tracks can't crawl over things more than a fraction of the dimension of their body. A hopping robot can clear things that are ten to one hundred times its body dimension." The mines will have a powerful piston-driven foot attached to their base that should propel them more than 10 metres into the air.
The self-righting mines will detect the distance to their neighbours using ultrasonic sensors and communicate with each other by radio. If some of the mines are removed or destroyed to make a path through the minefield, the remaining mines will sense that they are missing and hop around until they form a regular pattern again. DARPA wants the minefield to reorganise itself within 10 seconds.
"The advantage of mines is that they are cheap, simple and effective," says Tony Howgate of the Battlefield Engineering Wing at Britain's Ministry of Defence. "This isn't going to be cheap or simple, and the more complicated it gets, the more unreliable it'll be," he says. He also wonders what will stop the hopping mines going astray. "How are you going to know where they've hopped to?" he asks.
Mark Hiznay of the pressure group Human Rights Watch in Washington DC says that the hopping mines must not be capable of inadvertent, accidental detonation by a person-a key tenet of the Ottawa Convention. "If the system meets the definition of the treaty, this could be a good alternative," he says. "The main concern we have is how sensitive the device's fuses are to the unintentional acts of a person. We're asking governments to clarify what physical forces are necessary to set off all types of mines."
Author: Ian Sample
New Scientist issue: 30 September 2000
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