Thirty-two years ago, the Air Force flew specially equipped B57 bombers through the mushroom clouds of nuclear bomb tests in the South Pacific to observe the radiation doses absorbed by crewmen, according to Defense Department documents obtained by a House subcommittee.

The project was intended to tell the Air Force "how much air space was excluded for follow-on strikes by manned aircraft" because of intense radiation after an initial nuclear attack, according to retired Air Force general Kermit C. Kaericher, who helped design the tests and flew as one of the half-dozen pilots and observers.

The six radiation tests, which included 27 separate passes through mushroom clouds by the bombers, were the only times that Air Force personnel, rather than unmanned drone aircraft, were sent directly through clouds, Kaericher said in a telephone interview from Indianapolis. During most atmospheric nuclear tests, which were banned in 1963, manned aircraft took samples of radioactive materials from the edges of clouds; aircraft often were aloft at the time of detonation to measure blast and other effects.

In sending the report on Operation Redwing, a series of nuclear tests in the 1950s, to Rep. Edward J. Markey (D-Mass.), the Department of Energy described the "early cloud penetrations" as one example of "human experimentation" with nuclear radiation.

Today, those "penetrations" will be publicized in a Senate hearing by veterans and other groups making a new attempt to obtain government compensation for servicemen exposed to radiation during U.S. nuclear weapons tests. For years the government has been involved in legal battles with servicemen exposed to radioactive fallout after nuclear detonations in Nevada and the South Pacific in the 1950s and 1960s.

At today's hearing, the Environmental Policy Institute (EPI), a public interest group that frequently studies nuclear issues, will release an analysis of the Redwing project which questions earlier Defense Nuclear Agency (DNA) reports on radiation levels at the U.S. nuclear tests.

For example, EPI notes that the new study points out that sensitive recording devices on the aircraft recorded much higher dosage levels than the badges worn by the crew. The study went on to note that the instruments were "more sensitive to soft gamma radiation than the film dosimeters badges ."

Many of the veterans seeking compensation, turned down in the past because their records showed low dosages, have argued that their badges failed to record low-level radiation. However, the DNA's own 1982 report on Redwing said the badges were accurate, according to EPI.

But according to initial data gathered by the DNA and Kaericher, the small number of Redwing pilots and observers may not support arguments that their relatively large exposure levels have resulted in any abnormal rates of cancer or other radiation-related diseases.

Kaericher said he flew through the cloud of a 5-megaton shot 22 minutes after it exploded and received a dose of 17 rads, a radiation exposure measured by sensitive badges.

The current permissible occupational dose set by the Nuclear Regulatory Commission is about five rads for one year.

The retired officer said he is in good health and "playing golf every day." He added that the chief scientist in the project, retired general Ernest A. Pinson, who flew more missions than anyone, is also in good health.

A DNA spokesman said that six other participants had recorded doses above five rads and that the agency had attempted to contact them as part of an earlier study to encourage physical examinations for all servicemen exposed to that level.

The spokesman added that those in the high-exposure group from the cloud penetrations study "are all in good health," as far as the agency can determine.

According to the Redwing report, the cloud penetration project involved 78 men overall. Twelve were scientists and 66 were air and ground crew.

The manned flights through the mushroom clouds were made anywhere from 20 to 78 minutes after detonation, according to the report.

Dose rates as high as 800 rads per hour were recorded by some aircraft and "several flights yielded total radiation doses to the crew of 15 rads, as measured by film badges, and 35 to 40 rads, as measured by instrumentation."

The overall dose to crew members was divided into two parts -- that received in the cloud and a second-hand dosage absorbed on the return flight from the plane, which had become radioactive.

In the latter case, it was found that 15 percent of the overall dosage came during the return flight.

In addition, crews that serviced the aircraft also received radiation since the overall level of radiation for the entire unit was put at nearly two rads, according to DNA.

Markey, in a letter seeking more information from Defense Secretary Caspar W. Weinberger, said the crews were "needlessly exposed in this operation" and thus used "as guinea pigs."

Markey also pointed out that the Air Force surgeon general had granted a special dose authorization for the air crews on this project of 50 rads, far higher than the 3.9 rads set for other participants in Operation Redwing.