A powerful electrical storm, with gale-force winds, blocked radio communications and kept Navy divers from searching the ocean floor for remains of the space shuttle Challenger today.

National Aeronautics and Space Administration officials said that they probably have located a large booster that was supposed to launch a $100 million communications satellite, but that rough weather has interfered with sonar navigation devices on the U.S.S. Preserver.

The Preserver, a salvage ship with 22 Navy divers on board, left Port Canaveral at about 7 a.m., after Coast Guard vessels stopped searching the Atlantic for debris of the spacecraft.

But a Navy spokesman said the electrical storm hampered communication with the shore and prevented the crew from fixing a position over the booster, which is known as an inertial upper stage (IUS). The Navy said it would try to send two scuba divers down this evening to look at the wreckage if the weather cleared.

"They are having real trouble getting fixed over that spot," said Cmdr. Arthur E. Norton, a Navy spokesman, of the underwater sonar search. "They are having trouble bouncing the radio signals down there."

The Preserver, which is equipped with booms that can lift up to 10 tons of material from the ocean floor, can stay at sea for periods of about five days, the Navy said.

Space agency officials said they think the Navy was first trying to recover the IUS, rather than right-hand rocket booster that flared irregularly seconds before the shuttle exploded on Jan. 28, because the IUS was located in relatively shallow water of 120 feet.

If the IUS is salvaged, it could shed light on the effects of the explosion and possibly help answer questions about what caused it, NASA spokesman Jim Mizell said.

The 17-foot-by-10-foot IUS, which weighs about 32,000 pounds, was thought to have survived the explosion almost intact. It normally carried a load of 27,400 pounds of solid propellant and was to have sent its satellite into permanent orbit 22,300 miles above the Earth.

NASA officials have said that the solid rocket booster is immersed in 1,100 feet of water, and the Navy is preparing to send a separate ship to photograph and retrieve that booster.