Vision and Voyages for Planetary Science in the - Solar System ...

Nili Fossae region: A fracture in the surface of Mars that has been eroded and partly filled in by
sediments and clay-rich ejecta from a nearby crater.
NIMS: Near-Infrared Mapping Spectrometer.
NLSI: NASA Lunar Science Institute.
NOAA: National Oceanic and Atmospheric Administration.
Noachian epoch: The oldest of three time periods into which the geologic history of Mars has been
divided, spanning from about 4.1 billion to about 3.5 billion years ago.
NOAO: National Optical Astronomy Observatory.
NOSSE: The NRC report New Opportunities in Solar System Exploration.
NRA: NASA Research Announcement.
NRAO: National Radio Astronomy Observatory.
NRC: National Research Council.
NSF: National Science Foundation.
Nucleosynthesis: The process by which chemical elements are produced from light elements, occurring
in stellar interiors and during supernovas.
Nucleotide: A class of organic molecules that play a variety of important roles in biological processes.
They form, for example, the major structural subunits of DNA and RNA and serve as a source of energy
for biochemical processes.
O2: Molecular oxygen.
Obliquity: The angle between an object’s rotation axis and the pole of its orbit.
Occultation: The passage of an astronomical body across the line of sight to another astronomical body
of smaller angular diameter; i.e., a planet passing across the line of sight to a background star.
OLAF: On-Line Archiving Facility.
Olivine: A magnesium iron silicate mineral (FeMg)2SiO4.
Oort cloud: A spherical distribution of comets having semimajor axes between 1,000 and 50,000 AU,
typically with low orbital eccentricity.
OPAG: Outer Planet Assessment Group.
Opportunity: The secong of the two rovers of NASA’s ongoing Mars Exploration Rover mission which
landed on Mars on 25 January, 2004.
OPR: Outer Planets Research.
OPRP: Outer Planets Research Program.
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