The Pershing II and cruise missiles scheduled to be deployed in Western Europe hold the promise between them of great improvements in speed, accuracy, range and flexibility.

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 Ia, 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. The guidance system is 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 say a mixed Pershing II-cruise missile force provides the flexibility to select the best weapon for any given mission.