Pentagon says Soviets are at work on missile able to evade `star wars' defense

The Soviet Union is trying to build a nuclear missile warhead that could slip undetected past US warning radars, says a senior administration official. Such a ``stealth'' warhead, if perfected, could be useful against any US ``Star Wars'' strategic missile defenses. It would use camouflage techniques such as those being developed by the US for its next generation bomber.

Revelation of this research was one of the highlights of the Pentagon's release of ``Soviet Military Power.'' It is an annual volume that assesses developments in the USSR's armed forces.

``They have more weapons, of higher quality, higher capability,'' said Defense Secretary Caspar W. Weinberger at a briefing on the report.

But because of the Pentagon spending increases of 1981-85 ``we have definitely improved our relative position,'' he said.

Within the past year, according to the Pentagon, the Soviet Union has:

Continued to modernize its arsenal of intercontinental ballistic missiles, with an emphasis on new mobile systems. The new, road-mobile SS-25, about the size of the US Minuteman, has now entered service, with several bases and over 70 launchers operational. The larger SS-X-24, carried on railroad cars, could be deployed as soon as the end of this year, claims the Pentagon.

Built up its force of nuclear-missile armed submarines. A fourth Typhoon class strategic sub, and a third Delta IV class, have been launched in the last twelve months.

Moved to attain parity with the US in cruise missiles, small jets which fly to their targets like unmanned airplanes. A senior Administration official said, ``After what we percieved to be a relatively late start, they're coming on like gangbusters.'' A Soviet cruise missile launched from airplanes is already operational; last year saw advanced testing of sea- and ground-launched versions of the same weapon.

Begun building a second 65,000 ton displacement aircraft carrier, similar to big US flattops. The Soviets' first such ship was launched a year ago.

Tested a heavy-lift booster rocket capable of sending aloft the Soviet version of the space shuttle, now being developed.

Deployed the Su-27 FLANKER fighter aircraft, a new generation warplane similar to the US F-15 Eagle.

Though ``Soviet Military Power'' does list US military forces, critics charge that it often downplays the size and capability of the NATO arsenal that is the counterbalance to the USSR.