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National Aeronautics and Space Administration
Industry: Aerospace
Number of terms: 16933
Number of blossaries: 2
Company Profile:
The Executive Branch agency of the United States government, responsible for the nation's civilian space program and aeronautics and aerospace research.
A small motion in the Earth's rotation axis relative to the surface, discovered by American astronomer Seth Carlo Chandler in 1891. Its amplitude is about 0.7 arcseconds (about 15 meters on the surface) with a period of 433 days. It combines with another wobble with a period of one year, so the total polar motion varies with a period of about 7 years. The Chandler wobble is an example of free nutation for a spinning non-spherical object.
Industry:Aerospace
The inward acceleration of a body revolving around another body.
Industry:Aerospace
The outward-tending apparent force of a body revolving around another body.
Industry:Aerospace
Reflecting scheme in antennas and telescopes having a primary and a secondary reflecting surface to "fold" the EMF back to a focus near the primary reflector.
Industry:Aerospace
The main frequency of a radio signal generated by a transmitter prior to application of any modulation.
Industry:Aerospace
c
The speed of light, 299,792 km per second.
Industry:Aerospace
A modulation scheme in which data symbols are represented by a shift from one phase to another. See Chapter 10.
Industry:Aerospace
In the U.S., 109. In other countries using SI, 1012.
Industry:Aerospace
Downlink from a spacecraft that immediately indicates the state of the spacecraft as being one of several possible states by virtue of the presence and/or frequency of the subcarrier. See Chapter 10. Bel - Unit of ratio equal to ten decibels. Named in honor of telecommunications pioneer Alexander Graham Bell.
Industry:Aerospace
A unit of ratio equal to ten decibels. Named in honor of telecommunications pioneer Alexander Graham Bell.
Industry:Aerospace