+ 1970 News Releases (7.6 Mb PDF file) - NASA

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N,-,TIONAL AERONAUTICS AND SPACE ADMINISTRATION
MANNEDSPACE[RAFT
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483-5111 February 17, 1970
MSC 7O-27
HOUSTON_ TEXASl-Scientific instruments left on the Moon by the
Apollo 12 crew are expected to record possible thermal "shock"
effects on the lunar surface during a lunar eclipse on February 21_ 1970.
The lunar eclipse_ a twice a year event_ is caused by the Earth
blocking out the rays of the Sun. This turns lunar day into partial
lunar night causing a thermal "shock_" the effects of which will be
measured and transmitted to Earth by the Apollo 12 Lunar Surface
Experiment Package (ALSEF). The eclipse will start at 12:55 a.m. CST,
Saturday_ February 21_ 1970.
Scientists at the NAS& Manned Spacecraft Center anticipate the
thermal "shock" to crack rocks_ release entrapped gases_ make the lunar
surface tremble and modify the electric fields near the lunar surface.
The Apollo Lunar Surface Experiment Package (ALSEP) will be in the
shadow caused by the passage of the Earth between the Sun and the Moon.
The ALSEP gives man the first opportunity to study the results of
such an eclipse on the lunar surface. The array of scientific instruments
has been in continuous operation since its emplacement on the Moon by the
Apollo 12 crew on November 20, 1969.
"We will possibly see the effect of the release of entrapped
gases from the lunar surface/' Dr. John Freemah_ Associate Professor
of Space Sciences_ said of the eclipse. Dr. Freeman is principal
investigator of the ALSEP's lunar ionosphere detector which is designed
to study the charged particles in the lunar atmosphere.
Five instruments_ a power souree_ and data system comprise the
ALSEP which will study the eclipse and transmit the data to the Mission
Control Center at MSC.
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