LANDMINES that hop around to foil the crews that clear minefields are under
development in the US. The so-called 鈥渟elf-healing鈥� 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鈥攁lready signed by more than 135 countries鈥攚hich 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 鈥渋ntelligent鈥�
minefields.
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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. 鈥淚 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,鈥� he says. 鈥淚 said
to myself: `I can build a robot that can do that.'鈥�
Hopping has a distinct advantage over more conventional means of getting
about, says Robinett. 鈥淩obots with wheels and tracks can鈥檛 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.鈥� 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.
鈥淭he advantage of mines is that they are cheap, simple and effective,鈥� says
Tony Howgate of the Battlefield Engineering Wing at Britain鈥檚 Ministry of
Defence. 鈥淭his isn鈥檛 going to be cheap or simple, and the more complicated it
gets, the more unreliable it鈥檒l be,鈥� he says. He also wonders what will stop the
hopping mines going astray. 鈥淗ow are you going to know where they鈥檝e hopped to?鈥�
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鈥攁 key tenet of the Ottawa Convention. 鈥淚f the system meets the
definition of the treaty, this could be a good alternative,鈥� he says. 鈥淭he main
concern we have is how sensitive the device鈥檚 fuses are to the unintentional
acts of a person. We鈥檙e asking governments to clarify what physical forces are
necessary to set off all types of mines.鈥�
