Glossary of Terms
Agglutinates - common
particle type in lunar sediment. Agglutinates consist of
small rock, mineral, and glass fragments which are bonded
together with glass.
ALSEP - Acronym for the Apollo Lunar Surface Experiments
Package. The precise makeup of the instruments for each
ALSEP varied from mission to mission.
Apollo - U.S. space program which included 6 piloted
lunar landings between 1969 and 1972.
Astronaut - Person trained for spaceflight.
Basalt - Fine-grained, dark-colored
igneous rock composed primarily of plagioclase feldspar
and pyroxene and other minerals.
Basin - A large impact crater,
usually with a diameter in excess of 100 kilometers. Most
basins have been modified by degradation of the original
basin relief through downslope movement of debris and flooding
of the basin interior by lavas.
Breccia - Rock consisting
of angular, coarse fragments embedded in a fine-grain matrix.
Core - The central region of a planet or moon which
is frequently made of different materials than the surrounding
regions. Earth and Moon are thought to have cores of iron
Crater - A hole or depression. Most are circular
or oval in shape. On the Moon most are made by the impacts
Crust - The outermost layer of a planet or moon
above the mantle.
Descartes - Lunar highlands site of the Apollo 16
landing on April 21, 1972.
Ejecta - The material thrown
out from and deposited around an impact crater.
EVA - Acronym for Extra-Vehicular
Activity - any activity that takes an astronaut outside
the spacecraft during the mission.
Farside - The side of the Moon that never faces
Fra Mauro - Landing site of Apollo 14 on the Moon
on Feb. 5, 1971.
Giant impact theory - An explanation for the origin
of the Moon from Earth debris which collected in space after
a body the size of the planet Mars smashed into a growing
Gibbous moon - The phase of the Moon during which
more than half, but less than all, the visible hemisphere
of the Moon is illuminated by sunlight.
Hadley-Appenine - Landing site of Apollo 15 on the
Moon on July 31, 1971.
Highlands - The oldest exposed
areas on the surface of the Moon. Highlands are extensively
cratered and differ chemically from the maria.The densely
cratered portions of the Moon that are typically at higher
elevations than the mare plains. The highlands contain a
significant proportion of anorthosite, an igneous rock made
up almost entirely of plagioclase feldspar.
Igneous - Rocks formed by
hardening of hot, molten magma.
KREEP - On the Moon this type of hilands rock is
rich in potassium (K), rare earth elements (REE) and phosphorus.
Lava - A volcanic rock protruded by the eruption
of molten material. LVR - Acronym for Lunar Roving Vehicle
Lunar - Of or pertaining to the Moon.
Magma - Term applied to molten rock in the interior
of a planet or moon. When it reaches the surface, magma
is called lava.
Maria (Mare) - Dark areas on
the Moon covered by basalt lava flows. The low albedo plains
covering the floors of several large basins and spreading
over adjacent areas. The mare material is comprised primarily
of basaltic lava flows, in contrast to the anorthosites
in the highlands.
Metamorphic - Rocks that
have recrystallized in a solid state as a result of changes
in temperature, pressure and chemical environment.
Meteorite - A metallic or
stony body that has fallen on Earth or the Moon from outer
Moonquake: Sudden motion
or trembling of the Moon cause by the abrupt release of
slowly accumulated energy in rocks.
Nearside - The side of the Moon that always faces
Newton's Third Law of Motion - Rockets are based
on this principle. The third law states that for every action
there is an equal and opposite reaction.
Norite - Igneous rock found
in the lunar highlands.
Ocean of Storms - Landing site of Apollo 12 on the
Moon on Nov. 19, 1969.
Orange soil - On the Moon, a mixture of very small
dark orange and black glass balls which formed from quickly
cooled lava droplets.
Ray - Streak of material blasted
out and away from an impact crater.
Regolith - Loose, unconsolidated
rock, mineral and glass fragments. On the Moon this debris
is produced by impacts and covers the surface.
Rille - Long channel on the
Moon crossing the surface of maria. It was probably formed
either as an open channel in a lava flow or as an underground
tube carrying hot lava which collasped as the lave flowed
out. One of the several trenchlike or cracklike valleys,
up to several hundred kilometers long and 1-2 km wide, commonly
occurring on the Moon's surface. Rilles may be extremely
irregular with meandering courses ("sinuous rilles"), or
they may be relatively straight ("normal rilles"). They
have relatively steep walls and usually flat bottoms.
Secondary craters - Craters produced by the impact
of debris thrown out by a large impact event. Many secondary
craters occur in clusters or lines where groups of ejecta
blocks impacted almost simultaneously.
Rocket -A device shaped like a cylinder that moves
at high speed, powered by gases that are forced out of one
end. Considered the oldest form of self-contained propulsion.
They carry their own oxygen and can go where ther is no
air into space. They can burn liquid or solid fuel.
Saturn V - Vehicle which carried the Apollo spacecrafts
to the moon. 363 feet (111 meters) in height.
Sea of Serenity - One of the maria or "seas"
on the Moon's nearside. Also called Mare Serenitatis.
Sedimentary - Rock formed
when sediment is compacted.
Taurus-Littrow - Landing site of Apollo 17 on the
Moon on Dec. 11, 1972.
Terrain - Area of the surface with a distinctive
Troctolite -Igneous rock
found in the lunar highlands.