U.S. and Russian astronauts working on the international space station should limit their exposure to radiation during intense solar activity, a scientific advisory panel recommended yesterday.

Plans for construction of the space station by 2004 call for 43 space shuttle missions and about 1,500 spacewalks.

This work will coincide with the peak of the 11-year cycle of solar activity next year, the National Research Council noted in its report.

The council recommended that the National Aeronautics and Space Administration take extra precautions to protect astronauts from dangerous radiation, including seeking additional data on when solar storms occur so astronauts can be warned.

NASA and the National Oceanic and Atmospheric Administration are already cooperating on monitoring the sun's activity.

One satellite, already orbiting a million miles from Earth, will detect a rise in charged solar particles and give an hour's warning of dangerous radiation arriving. That warning also will allow spacewalking astronauts to seek the safety of the shuttle or the space station.

The council also urged adding radiation exposure meters to spacecraft as soon as possible to determine the amount of exposure during a flight.

The council is an arm of the National Academy of Science, which provides scientific advice to government agencies.