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DESTINATION MOON: A History of the
Lunar Orbiter Program
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- APPENDIX A
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- GLOSSARY
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- [361] albedo
- The ratio of the amount of electromagnetic
radiation reflected by a body to the amount incident upon it. This
concept is identical with reflectance but should be distinguished
from spectral reflectance.
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- anomaly
- In general, a deviation from the norm, an
irregularity, a malfunction.
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- apolune
- That point in a lunar&endash;centric orbit
which is most distant from the Moon.
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- Bimat web
- The continuous processing film used in the
Lunar Orbiter photographic subsystem to process the camera
film.
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- deboost
- A velocity control engine burn to allow a
spacecraft to decelerate and go into orbit around a planetary
body, or to leave an orbit and descend to a landing on that body.
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- delta V
- A change in velocity.
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- flux
- The rate of flow of some quantity, often
used in reference to the flow of some form of energy.
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- gimbal
- A device with two mutually perpendicular
and intersecting axes of rotation. It provides free angular
movement in two directions and serves as an engine mount.
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- Greenwich Mean Time (GMT)
- The local mean time at the Greenwich,
England meridian. Some of the Lunar Orbiter post&endash;launch
operations reports used the local time at the Kennedy Space
Center, expressed either in Eastern Standard Time (EST, 5 hours
behind GMT) or Eastern Daylight Time (EDT, 4 hours behind GMT),
depending on the time of year when a launch took place.
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- ground resolution
- The degree to which an optical or
photographic system can reproduce fine detail of the surface being
imaged, as measured against a photographic scale. It is the
product of a combination of capabilities of the film (graininess,
sensitivity, etc.) and the lens (type, resolving, power, etc.) and
is usually expressed in line pairs per millimeter. Photographic
scale is found by dividing the altitude at which the picture is
taken by the focal length of the camera. For Lunar Orbiter, the
[362]
effective film resolution was 76 line pairs per millimeter, which
gave 1-meter resolution through the 610 mm lens and 8-meter
resolution through the 80 mm lens under predetermined contrast
conditions on the lunar surface.
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- hypergolic
- A term used to describe propellants that
ignite spontaneously on contact with an oxidizer; a self-igniting
fuel, propellant, or propulsion system.
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- launch window
- The postulated opening in a continuum of
time or space through which a spacecraft must be launched to
achieve a desired encounter, rendezvous, or impact.
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- noise level
- The level of any undesired disturbance
within a useful frequency band.
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- nominal
- Occurring or performing as intended in
pre-mission planning.
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- oxidizer
- A substance that combines with another to
produce heat and, in a rocket, hot gases of combustion
thrust.
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- parking orbit
- A temporary orbit in which a vehicle
coasts before transfer into final orbit or trajectory.
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- perilune
- The point in a lunar-centric orbit which
is closest to the Moon.
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- pitch
- An angular movement (of a spacecraft)
about an axis parallel to the lateral axis of the vehicle.
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- roll
- The rotational or oscillatory movement of
a spacecraft or similar body about a longitudinal axis through the
spacecraft.
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- software
- (Computer) programs and formulation of
programs.
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- yaw
- The rotational or oscillatory movement of
a spacecraft or the like about a vertical axis.
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- Sources:
- - Charles McLaughlin Space Age Dictionary (Princeton: D. Van Nostrand Co., 1959).
- - William H. Allen, ed., Dictionary of Technical Terms for Aerospace
Use, NASA SP-7 Washington., D.C.:
GPO, 1965).
- - J. L. Nayler, A Dictionary of Astronautics (New York: Hart Publishing Co., 1964 )
- - Woodford A. Heflin, ed. The United States Air Force Dictionary
(Air University Press,
1956).
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