MIL-HDBK-143A
dry emplacement - A launch facility that has no provision for water cooling of Rocket exhaust
blast during launch. Also called dry stand.
dry stand - See: dry emplacement.
dual modulation - The process of modulating a single carrier wave or sub-carrier by two
different types of modulation, amplitude, and frequency, each conveying separate information.
dual thrust - A Rocket thrust force derived from two Propellant grains using the same
propulsion section of a missile. Used to provide two-stage propulsion without the need for
jettisoning of booster stages.
dual-thrust motor - A solid-Propellent ROCKET MOTOR built to obtain dual thrust. Can
consist of a single combustion chamber with both booster and sustainer grains and a
mechanical throat nozzle or two separate chambers in tandem.
duration, shutdown - The interval in time between shutdown signal and thrust deletion.
duration, total - The total firing time in seconds from the start of the rise in thrust to the end of
the thrust tail-off.
dynamic load- For aircraft or missiles, a load or force generated by acceleration of the vehicle
by wind gusts, maneuvering, or landing, as distinguished from static loads.
dynamic model - A model of a missile or other vehicle reproduced in a scale (dimensions,
weight, and moments of inertia) proportionate to the original.
E
earth-rate correction - A command rate applied to a gyro to compensate for the apparent
precession of the gyro spin axis with respect to its base, caused by the rotation of the earth.
earth-rate unit - A unit of angular draft as of a gyro, equal to the rate of angular movement of
the earth with respect to the stars, 15 degree/hours.
ECCM* - Electronic counter-countermeasures,
ecliptic - Plane of the earth's orbit around the sun, used commonly as a reference for other
interplanetary orbits.
ECM* - Electronic countermeasures.
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