EDITORIAL : A HEALTHY UNION BOEING'S PLAN TO BUY ROCKETDYNE APPEARS TO BE POSITIVE NEWS FOR BOTH COMPANIES.

FOR half a century, including more than 40 years in the San Fernando -Valley, Rockwell International has had a major and illustrious presence in Southern California.

Rockwell's aerospace and defense unit, the Rocketdyne Division in Canoga Park, has engineered and built the engines lifting every manned U.S. flight into space. When astronaut Neil Armstrong stepped foot on the moon in 1969, he did so from Rockwell-built Apollo service and command modules that were propelled by Rocketdyne engines. When the space shuttle Columbia made its inaugural flight in 1981, it was powered by three Rocketdyne main engines.

Rocketdyne's spectacular successes through the years created jobs and helped spur the Valley's growth and development, resulting in a great and successful partnership. Only once has the relationship been marred. That occurred in 1994 when an explosion at the Santa Susana facility in Chatsworth killed two workers. Rockwell pleaded guilty in April to criminal charges of illegally storing and disposing of hazardous waste.

That tragedy aside, Rockwell and its Rocketdyne division have been excellent corporate neighbors. Rocketdyne workers donate nearly $30,000 every week out of their paychecks to support charities. In addition, the corporation kicks in about $500,000 annually to nonprofit organizations.

Now the question becomes, will that good neighbor tradition continue with Rocketdyne's new owner, the Boeing Co.? The signs appear positive.

Thousands of jobs have been lost during the downsizing - often accompanied by mergers - of the aerospace and defense industries in Southern California in the 1980s. However, the acquisition announced Thursday by Boeing has the potential for growth.

Jerry King, president of Boeing's Defense & Space Group, said that no major layoffs are planned for the 21,000 workers in Southern California. And Boeing will move into Rockwell's Seal Beach headquarters, maintaining a presence here.

What makes this merger different from others is that it provides both Rockwell and Boeing with new opportunities for growth. For Boeing, the largest aircraft manufacturer in the world, the move adds programs ranging from the space shuttle and the B-1B bomber to satellites, rocket engines and airborne lasers.

With the Cold War over and the defense industry undergoing huge consolidations, Rockwell was being realistic in focusing on such products as computer modems, factory robots and auto parts. It sees more future in those products than in space shuttles and now has the cash to expand.

All in all, the announcement is encouraging for employees - and the economies - of the Valley and Southern California. This appears to be a good corporate fit - and a comfortable one for Rocketdyne employees who have planted roots in the Valley.