WASHINGTON - A leading group of space scientists, with the endorsement of Vice President Dan Quayle, is calling for an international effort to hunt down and destroy - perhaps with nuclear weapons and modified ``Star Wars'' gear - asteroids headed toward Earth.
``Earth orbit-crossing asteroids clearly present a danger to the Earth and its inhabitants,'' the American Institute of Aeronautics and Astronautics said in a position paper distributed Monday. ``Although no fatalities have yet been recorded as a consequence of such events, the impact of even a rather small object would have a devastating effect on humanity.''
Quayle, chairman of the National Space Council, recently supported the institute's initiative.
``In 1965, a small asteroid exploded high over Canada with a force equivalent to an atomic bomb,'' he told the group's annual meeting on May 1. ``It would certainly benefit all nations to know when such a natural event might occur, warn those who could be affected, and, maybe someday, even affect whether and where such an event might happen.''
The institute recommends that an international group of astronomers, aided by military satellite-tracking equipment, search the skies for asteroids and track their orbits so any collisions can be anticipated and then prevented.
``If we know where they are and know where they're going, then maybe we'll have time to do something about it,'' Jerry Grey, director of the institute's science and technology policy, said Monday. ``A missile with a nuclear warhead would do it fine.''
Asteroids are extremely small planets that circle the sun, largely between Mars and Jupiter. There are about two dozen asteroids more than 100 miles across and thousands more than five miles wide.
Scientists estimate that as many as 1,500 asteroids travel in orbits that cross the Earth's path around the sun, although
the locations of fewer than 100 are known. ``We don't even know where these objects are,'' the position paper said. ``Any one of them could strike the Earth without warning.''
The last major asteroid to come close to the Earth passed within 400,000 miles - nearly twice the distance between the Earth and the moon - in March 1989. If it had hit the Earth, the half-mile wide body would have struck with the force of up to 200,000 Hiroshima-sized nuclear bombs. ``In an area of high-population density such as the northeast corridor of the United States, Los Angeles, or Tokyo, millions of people would have died instantly,'' the paper said.
The paper, ``Dealing with the Threat of an Asteroid Striking the Earth,'' said a 10-mile wide asteroid would hit with a force 10,000 times that of the superpowers' combined nuclear arsenals, and can be expected once every 50 million to 100 million years. Some scientists believe such a collision 65 million years ago wiped out the dinosaurs.
Weapons being designed for the Strategic Defense Initiative, popularly known as ``Star Wars,'' could be developed to destroy any asteroid bearing down on Earth, the paper said.
It added, however, that the system would have to be ``able to make the interception far enough from the Earth to prevent damage to its inhabitants. Since the systems needed might require the use of nuclear warheads, there would have to be international agreement on when an interception is needed.''
``It's not part of our mission,'' said Army Maj. William O'Connell, a spokesman with the Strategic Defense Initiative Organization. ``We look at the ICBM problem and not the asteroid problem.''
The American Institute of Aeronautics and Astronautics, a Washington-based group, has 40,000 members interested in improving U.S. technical prowess in space.