HAARP is a facility to study upper atmospheric and solar terrestrial physics. The programme is paid for by the US Air Force and Navy and has already cost hundreds of million dollars. Opponents of the project believe that the defence department is studying ways of improving communications with the US submarine fleet. The array acts like a powerful radar and transmits high frequency 3600 kW signals into the ionosphere.

Starting 35 miles above the Earth's surface, the ionosphere contains charged particles which distort and deflect radio signals. These particles are produced by the interaction of solar radiation with the atmosphere. HAARP can pump energy some 70 miles into the ionosphere diameter. Military applications for such phenomena are many - devising radar systems, disrupting communications, and improving US logistics.

When the foreign affairs committee invited North Atlantic Treaty Organisation (NATO) and the US permanent representative to NATO to discuss the HAARP project at a public meeting two weeks ago, both groups refused. The secretary general of NATO said that the organisation had neither a policy on this topic, nor an expert they could send to the committee. Tom Spencer, chairman of the committee chairman, vowed to take the matter further, possibly to the US Congress.

Not all researchers believe that opposition to HAARP is justified. Peter Cargill, a space physicist at Imperial College in London, believes that the physics is interesting in its own right, and points out that there are several other facilities carrying out this type of research. "HAARP is just bigger than the other programmes around the world, " he says. "However, the military don't spend that kind of money for pure science."