What are the two new, intermediate-range missiles whose prospective deployment has caused such a furor in Europe?

The Pershing II will be a mobile, solid-fueled ballistic missile that can travel about 1,000 miles from a West German base within six to eight minutes and deliver its 200-kiloton warhead (1 kiloton is equivalent to 1,000 tons of TNT) on targets within the Soviet Union. It will replace in U.S. units the Pershing I, which has a range of 400 miles and cannot reach into the Soviet Union from West Germany.

The Pershing II, whose speed is regarded as a new dimension of threat by the Soviet Union, also promises a tenfold improvement in accuracy over its predecessor thanks to a terminal guidance system controlled by an onboard radar, which coordinates images obtained as it closes in on the target with a prestored reference map of the target area. Its greater accuracy makes it useful as a selective strike weapon.

The ground-launched cruise missile, which travels more slowly, is valued most for its penetration ability. Like the Pershing II, it will also be mobile but has a slower, turbofan engine that would require up to 30 minutes to travel its 1,500-mile range.

Unlike the Pershing II, however, it would be able to reach the Soviet Union from as far away as Sicily and England.

The cruise also will be highly accurate, guided by a terrain contour matching system that allows it to fly less than 50 feet above the ground, evading enemy radar on a prestored flight path leading to the target.

NATO officials justify a mixed Pershing II-cruise missile force as a hedge against failure of one type of system. They also say such a mix provides the flexibility to select the best weapon for any given mission.

The cost of the development and production of the new Pershing II and cruise missile systems, estimated at $5 billion, is to be paid by the United States. NATO allies will contribute through the alliance to the infrastructure and support of the system.

In the discussions that led to the December 1979 NATO decision on deployment of the new weaponry, there was some thought given, at the instigation of West German Chancellor Helmut Schmidt, to placing the cruise missiles at sea instead of on land.

But the sea-basing idea was dismissed by NATO planners as more expensive and presenting command, control and communication problems.

Perhaps most important, sea-based missiles were said to lack the visibility thought necessary for theater nuclear force modernization to demonstrate NATO's resolve. Moreover, they would complicate East-West arms limitation talks by posing major verification and perception problems for the Soviets.

Whether these arguments were what finally convinced Schmidt to drop the sea-basing idea is not altogether clear.

"There is more than a hint that Europe and America were caught in a game of mirrors," said Gregory Treverton of the International Institute for Strategic Studies in a recent paper, "with America arguing that only ground-basing would assuage European fears and West Germany in particular sensing a U.S. preference for land-based systems."