| definition |
- The Neutral Atmosphere Temperature Experiment (NATE) was designed
to measure the kinetic temperature of the neutral gas at the spacecraft.
Its design was based upon a technique first employed on the San Marco
III (a and b) satellites, and later the Aeros I and II satellites (Ref).
The measurement approach is based upon the concept that the neutral
particles, in this case N2, are in thermal equilibrium, and hence a
measure of their velocity distribution permits a kinetic temperature
calculation. The desirability of measuring the local kinetic tempera-
ture seems obvious - it is a basic parameter in atmospheric studies, and
it reflects local conditions of thermodynamic equilibrium and hence the
local dynamic situation. Most previous temperature measurements have in
fact been derived from density measurements, from the density scale
height, from ion temperature, or optically by observation of line widths,
Recent Aeros data analysis reveals temperature derived from density does
not always faithfully reflect the true temperature of the gas particularly
at times when a geomagnetic disturbance is influencing the atmosphere
(Ref).
The NATE also provided measurement of the composition, when
commanded into the appropriate mode and, for the first time, measurement
of the local wind:
AE-C Vertical motions
AE-D, E Vertical motions and horizontal (normal to orbit plane)
winds
[Summary provided by NASA]
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