Meteorite AHLA 81005 is about to become a star, of sorts. Scientists at the 14th Lunar and Planetary Science Conference in Houston are expected to confirm Thursday what many have suspected for months: that this fragment is actually a piece of the moon.
Of some 10,000 meteorites now in the collections of researchers, it is the first and so far the only one in history to have its place of origin identified. But AHLA 81005 may soon have to share some of the limelight. Armed with solid evidence that meteorites can be bits of planets, an increasing number of specialists are seriously considering a new theory. Nine rare SNC (shergottite, nakhlite, and chassignite) meteorites, collected over the last seven years, may well be chunks of Mars, they speculate.
Such discoveries are already causing scientists to ponder questions which they have not previously considered. The significance of this development has not been lost on those whose field stands to be the most enriched by it - planetary scientists.
''When you go back through history and rank the big events in the history of extraterrestrial material,'' says astrogeologist Bevan French, head of planetary materials research at NASA, ''you'd have to go back to the first discovery of meteorites as extraterrestrial, the return of the Apollo mission and its lunar samples, and now this discovery that meteorites came from the moon and perhaps Mars.''
Adds Johnson Space Center geochemist Donald Bogard, ''This is a hot topic in planetary science.''
Scientists say AHLA 81005 itself, discovered at Antarctica's Allen Hills region in January of 1982, will be a welcome addition to the lunar collection brought back by six Apollo missions. Such a find, adds Dr. French, is not unlike ''a free landing mission.''
It is improbable, they add, that the rock came from the small area covered by the Apollo missions (5 percent of the lunar surface). University of New Mexico geologist Richard Keil says the fragment is characteristic of the lunar highlands region covering most of the far side of the moon facing continually away from Earth.