Between 1969 and 1972 six Apollo missions brought
back 382 kilograms (842 pounds) of lunar rocks, core samples, pebbles, sand and
dust from the lunar surface. The six space flights returned 2200 separate
samples from six different exploration sites on the Moon. In addition, three
automated Soviet spacecraft returned important samples totaling 300 grams
(approximately 3/4 pound) from three other lunar sites. The
lunar sample building at Johnson Space
Center is the chief repository for the Apollo samples. The lunar sample
laboratory is where pristine lunar samples are prepared for shipment to
scientists and educators. Nearly 400 samples are distributed each year for
research and teaching projects.
Study of rock and soil samples from the Moon continues to yield useful
information about the early history of the Moon, the Earth, and the inner solar
system. Recent computer models indicate that the Moon could have been formed
from the debris resulting from the Earth being struck a glancing blow by a
planetary body about the size of Mars. The chemical composition of the Moon,
derived from studies of lunar rocks, is compatible with this theory of the
origin of the Moon. We have learned that a crust formed on the Moon 4.4 billion
years ago. This crust formation, the intense meteorite bombardment occurring
afterward, and subsequent lava outpourings are recorded in the rocks. Radiation
spewed out by the Sun since the formation of the Moon's crust, was trapped in
the lunar soil as a permanent record of solar activity throughout this time.
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