The top Sandinista military intelligence officer charged today that the United States has flown 121 spy flights this year over Nicaragua to glean information "like a vacuum cleaner" for the counterrevolutionary rebels known as contras.

Capt. Ricardo Wheelock, intelligence chief of the Sandinista Popular Army, said the spy planes gather electronic and photographic information providing the United States with "a complete X-ray every day" of the positions of Sandinista troops.

In Washington, a Pentagon spokesman declined to comment on the statements.

A bill to provide $100 million in aid for the contras, approved by the House of Representatives in June, greatly expands the mandate for the CIA and other U.S. intelligence agencies to assist the contras with sophisticated communications as well as training and tactical advice. It is expected to pass the Senate easily.

Wheelock said the aerial data-gathering is "the most important element, from our point of view" in U.S. operational support for the contras.

Wheelock said an RC135 had made 47 flights this year, monitoring telephone, radio and telex communications inside Nicaragua and overseas. Another aircraft, which Wheelock called a "U2 or TR1," made 13 flights, he asserted, snapping photos and making other electronic maps of airports, harbors and military installations. He said a U2 flew over Nicaragua today.

The U.S. Air Force maintains both RC135 and TR1 reconnaissance planes. The TR1 is a modernized version of the U2.

The officer said some of the flights have come within shooting range of Sandinista artillery but have never been fired on.

"We know what it would mean for us if we respond to a provocation," Wheelock said.

Wheelock said the United States also maintains at least three, and at times as many as 11, ships off Nicaragua's Pacific Coast to watch movements at the country's ports and airports. Normally, he said, the vessels include a "rocket-mounted frigate," a "high-resistance Coast Guard cruiser" and an intelligence vessel, the ARL24, based in the Panama Canal Zone.

In addition, the Sandinista commander alleged that aircraft supporting the contras had flown 152 missions from neighboring Honduras over Nicaraguan war zones this year, dropping supplies and "making tactical explorations." He charged that some planes belonged to the Honduran Air Force.

Wheelock said that Sandinista intelligence had detected 161 flights originating in Costa Rica.

Meanwhile, President Daniel Ortega Saavedra today inaugurated a Soviet Bloc earth station allowing Nicaragua to become part of the Soviet system of satellite communications, known as Intersputnik.

Wheelock did not say how the Sandinista government obtained the information about the spy flights. In the past year, the government has rapidly been completing an advanced East Bloc radar system for nationwide military communications, western diplomats here have said.

In a departure from customary practice, Wheelock also said 116 Sandinista Army soldiers have been killed this year in combat with contra guerrillas. He asserted that the contras killed 123 unarmed civilians. Government forces, he said, have killed 2,919 contras since January. The government rarely specifies its losses.