The White House has shot down an unprecedented proposal from the top "Star Wars" official for a joint U.S.-Soviet space mission in August, in which cosmonauts would have used NASA jetpacks to retrieve an experiment from a U.S. satellite, according to administration officials.

Space experts called the proposal "bizarre" and "wild," and one said it has a high "giggle factor."The plan was proposed by Air Force Lt. Gen. James A. Abrahamson, director of the Strategic Defense Initiative Organization (SDIO), as a "cooperative initiative" for President Reagan to present to Soviet leader Mikhail Gorbachev during their Moscow summit, according to the May 16 issue of Aviation Week & Space Technology magazine.

Abrahamson could not be reached for comment.

Administration officials confirmed the proposal but, one said, "The policy problems guaranteed it would never get off the ground."

The notion was considered particularly ironic in that it came from the SDIO, given the administration's expression of concern about Soviet access to vital U.S. technology.

Under the proposal, Soviet cosmonauts would have used American equipment to retrieve an American materials package from an SDI satellite, the Delta Star.

"There are many ironies associated with this," an administration official said.

The magazine quotes an administration official as having said: "The concept's got a wooden stake driven through its heart now, but you never know what's going to come out of the SDI during the next full moon."

The plan involved launching two manned maneuvering units (MMUs) on a Soviet Progress unmanned transport or a manned Soyuz craft to the Soviet space station Mir, and might have included one or more U.S. astronauts who would be launched to Mir on a Soyuz, the magazine reported. A second option was to use Soviet cosmonauts exclusively.

The crew would then use the MMU jetpacks to travel from Mir to the Delta Star satellite to retrieve a small package containing material samples to be analyzed later.

The National Aeronautics and Space Administration's Johnson Space Center and the Martin Marietta Corp. in Denver, which makes the jetpacks, began studying the technical obstacles to such a plan two months ago at the direction of SDIO, the magazine said.

Beyond the "giggle factor," said John Pike of the Federation of American Scientists, "I can see what they may have thought they were doing."

SDI officials, he said, might have been attempting to follow through on Reagan's expressed notion of sharing SDI missile-defense technology with the Soviets to bolster a troubled program.

They also might have been seeking to capitalize on the Soviets' ready access to space - their booster rockets and Mir space station - to retrieve the Delta Star experiment, he said. U.S. space ventures have been severely limited since the explosion of the shuttle Challenger in January 1986.

The Delta Star mission had been scheduled for August but has been delayed until next year.