WASHINGTON (AP) _ Sometimes, you just can't keep a blimp on the ground. Ask the Navy - it's thinking about returning them to active duty.

After bringing back World War II-era battleships, the Navy is looking into whether the surveillance role performed by blimps in that war can be updated for a new mission.

Six contracts have been awarded for feasibility studies on using blimps as radar platforms to travel with and protect combat ships.

The contracts focus on whether a new fleet of ''airships,'' packed with sophisticated electronics and built for endurance and resupply at sea like any other ship, could do a better and cheaper job of warning surface ships about approaching cruise missiles.

The contracts were awarded May 31 with little fanfare by the Naval Air Development Center in Warminster, Pa. Lt. Peter Johnstone, a Navy spokesman at the Pentagon, said they call for studies to be completed by December.

''You can't say we're bringing back the blimp yet,'' said Johnstone. ''But we have begun preliminary studies to determine feasibility and cost.

''We want to examine what new technologies have become available since the Navy last used airships in the 1960s,'' he said. ''The Navy is always interested in evaluating new concepts or weapon systems if they would contribute to greater effectiveness. And there have been a lot of technological changes over the past 20 years.''

According to the spokesman, the Navy awarded three contracts - worth $650,000 apiece - to the Goodyear Aerospace Corp., the Sperry Corp. and Litton Industries Inc., calling on them to study how modern blimps would be built and ''operational concepts'' for their use.

Three other contracts, worth $300,000 apiece, were awarded to Hughes Aircraft, Westinghouse Electric Corp. and the RCA Corp., calling for studies of whether it would be feasible to construct and operate large radar and sensor systems that could be carried by blimps.

The Navy said the new look at blimps was prompted by concern over the growing sophistication of Soviet cruise missiles, which can be fired by submarines at great distance from a surface ship, skimming over the water at such a low altitudes they are difficult to detect on radar.

Fred Nebiker, a Goodyear vice president, says radars carried aboard blimps could greatly expand the warning time for Navy vessels. Nebiker adds blimps could be produced today that would be faster, more maneuverable and more difficult to see than the type built by his firm and used to escort thousands of ships during World War II.

According to Barney Scofield, a Goodyear spokesman, the Navy at one point had almost 170 blimps available. The largest had patrol ranges of 2,800 miles and were effective in spotting enemy submarines.

''The blimps escorted 89,000 ships during the war without a single loss of shipping,'' Scofield said Thursday. ''And 24 years after the Navy shut down its 'lighter-than-air force,' it looks like they have a mission that perhaps you can't do any better way, providing a continuous eye-in-the-sky.''

The spokesman said modern blimps could be built that could accompany a Navy fleet wherever it went, cruising at an altitude of 5,000 feet to 10,000 feet and capable of being resupplied and refueled at sea. Such airships could replace helicopters and airplanes that now perform such surveillance missions but whose flight time is limited.

Although Scofield declined to discuss details of the Goodyear study, he did say the firm is contemplating a blimp that would be roughly twice the size of those maintained by the firm for public relations purposes.

They would be similar in size to the last blimps built for the Navy by Goodyear, or slightly more than 400 feet long and inflated with 1.5 million cubic fleet of helium, he added.

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