countdown

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countdown

[′kau̇nt‚dau̇n]
(aerospace engineering)
The process in the engineering definition, used in leading up to the launch of a large or complicated rocket vehicle, or in leading up to a captive test, a readiness firing, a mock firing, or other firing test.
The act of counting inversely during this process.
(communications)
The ratio of the number of interrogation pulses not answered by a transponder to the total number received.
(engineering)
A step-by-step process that culminates in a climatic event, each step being performed in accordance with a schedule marked by a count in inverse numerical order.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
The exhibition, called "T-Minus: Worcester to the Moon," celebrates the city's industrial role in the space race.
Yet here you are, at T-minus eight weeks 'til school's out--and you're still not quite sure if he's crushing back or just being friendly.
Later, on April 12, 1981, at T-minus zero - liftoff - I watched as Columbia, attached to the mother ship like a delicate moth, rose slowly and gracefully rotated as she soared into the heavens.