Ninety demonstrators were arrested in a nonviolent protest at a Lockheed Missile Corp. testing site near Santa Cruz. The demonstrators represented a variety of peace groups complaining that Lockheed tests components for the Trident missile and other weaponry. Lockheed laid off 230 employees at the site Monday and Tuesday in anticipation of the protest. However, the employees returned to work Wednesday and demonstrators conducted a sit-down in the roadway. Most of those arrested were given citations for trespassing and blocking a public roadway, and were released.