The next space shuttle, scheduled for launch Jan. 23, will carry a new military intelligence satellite that is to collect electronic signals and retransmit them to a U.S. receiving station on Earth, according to informed sources.

The satellite is to be released from the shuttle cargo bay and directed into geosynchronous orbit 22,500 miles above the western portion of the Soviet Union, they said. It will stay there because its speed will equal that of the Earth's rotation.

Data gathered could include radio signals from Soviet missile tests that could be used to verify compliance with arms-control agreements, sources said.

The $300 million satellite would be the most important and largest of the so-called signals intelligence, or "sigint," satellites, four or five of which already hover above the Soviet Union. Each earlier version has a distinctive visual and radar image that permits the Soviets to know what it is, if not exactly what it is collecting and transmitting, sources said.

On Monday, Defense Secretary Caspar W. Weinberger and other top Pentagon officials disclosed that they have taken unusual steps to hide the nature of shuttle flights involving military payloads. About one-third of more than 200 shuttle launches scheduled in the next 10 years are to be conducted by the military, and next month's is the first.

The Pentagon effort contrasts sharply with the open nature of space missions conducted by the civilian National Aeronautics and Space Administration but not with the customarily secret nature of Air Force satellite launches.

Despite the secrecy, information is available about previously launched intelligence satellites, as is information about the shuttle Discovery's mission next month.

The Pentagon rules would bar disclosing details of Discovery's operational schedule, making it more difficult for the Soviets to monitor the flight and track the satellite.

The Air Force initially wanted to keep the entire mission secret, NASA sources said. The Pentagon compromised with the agency.

Reporters are to be allowed to cover the launch at Kennedy Space Center in Cape Canaveral, and be informed of the landing time there 16 hours in advance. No public access to air-to-ground communications and no public announcements are expected during the flight unless a serious problem develops.

Relations between NASA and the Air Force have been strained over the last year as the military service has begun pressing Congress for funds to permit it to launch larger payloads and not depend on the space shuttle.

At a news briefing Monday, Brig. Gen. Richard F. Abel, Air Force director of public affairs, said the Pentagon would treat shuttle missions "as we do the deployment of air, land and sea forces."

He said, "We are working to deny our adversaries any information which might reveal the identity of the mission or its payloads."

"Speculation" by news organizations on military aspects of the mission would result in a Defense Department investigation into the source of the information, he added.

Several news organizations working on stories describing the military cargo reported being called by the Pentagon about two weeks ago asking that the stories be killed for national-security reasons.

William Gregory, editor of Aviation Week and Space Technology magazine, said yesterday that he obtained information from confidential sources regarding the cargo with the understanding that he would not publish it.

"We took this information in confidence, and we kept our word," Gregory said. He said that the Pentagon called about the story but that "the situation was moot by then because we didn't plan to run a story."

Walter Mears, executive editor of the Associated Press, said, "We were asked on national-security grounds not to carry a story, and we agreed."

CBS News spokesman Richard Drayne said Weinberger called network President Edward Joyce to express concern that a news story on the mission might jeopardize national security.

"Weinberger had gotten wind of the fact that we had some information on the military payload. Joyce made no commitment but, after looking at the story, he decided we didn't have enough to go with it at that time," Drayne said.

On Monday night, CBS correspondent David Martin, reporting the NASA-Pentagon news briefing on secrecy surrounding the mission, described the cargo only as a "new generation of intelligence satellite." Drayne said CBS has not guaranteed Weinberger that the network would withhold stories on the mission.

NBC News spokesman Andrew Friedman said Weinberger "told NBC News that a story we were planning to broadcast . . . could seriously endanger national security and asked us not to broadcast it. NBC decided after careful consideration to honor the secretary's request."

Pentagon sources indicated yesterday that officials are worried that still-secret specifics of the new satellite's capabilities, disclosed to several journalists, would be made public because of competitive pressure.

Public information available on planned military shuttle operations makes identification of Discovery's payload as a "sigint" satellite relatively easy, according to several military experts in Washington research organizations.

Placing a satellite in geosynchronous orbit, one source said, requires an inertial upper stage (IUS) engine. "The Air Force itself earlier this year said the IUS will be used on this flight," one expert said. Because the IUS failed to operate properly on a recent shuttle mission, additional publicity was given to its planned use on the military launch.

Only three types of U.S. military satellites are in geosynchronous orbit: those for early warning, communications and signals intelligence, the expert added.

At congressional hearings over the last two or three years, he said, officials disclosed that the first new early-warning satellite would not go on the shuttle until later in this decade. A communications satellite was launched recently, he added.

"That left only one other category," he concluded.

"Sigint" satellites have been functioning for 10 years or more. Earlier rocket-launched versions weighed about 2,500 pounds, sources said, while the new one could weigh at least 30,000 pounds, too heavy for launch by an existing U.S. rocket.

The booster-assisted shuttle can launch a 65,000-pound cargo.

"Sigint" satellites are distinctive because they have two large dishes said to be 75 feet wide and to reflect light very brightly in space. One dish collects data, and the other transmits it to a receiving station outside the continental United States.