This experiment measured the kinetic temperature of the neutral atmosphere by determining the
instantaneous density of molecular nitrogen in a spherical chamber coupled to the atmosphere through a
knife-edged orifice. Analysis of the measured molecular nitrogen density variation over a spin cycle with
a knowledge of the satellite's motion and orientation led to a determination of the ambient temperature,
independent of scale height. A measurement of the ambient nitrogen density was also obtained. An alternate
measurement of neutral temperature was also undertaken, using a baffle inserted in front of the orifice to
intercept a portion of the gas particle stream entering the chamber. When the satellite was in the despun
mode, the baffle was made to oscillate in the stepwise fashion to interrupt the particle stream seen by
the orificed chamber. These chamber density variations were interpreted to yield the neutral gas kinetic
temperature. A dual-filament ion source sampled the thermalized molecular nitrogen in the chamber and
produced an ion beam density proportional to the nitrogen chamber density. From the source, this ionized
nitrogen beam was directed from a quadrupole analyzer, tuned to pass those particles whose mass-to-charge
ratio (M/Q) is 28, on to an electron multiplier. The output pulses were amplified and counted in a 16-bit
accumulator. The experiment also provided measurements of neutral atmospheric composition, when commanded
into the appropriate mode and, for the first time measured the local wind (vertical motions). The wind values
were determined by measurement of the "stream" position relative to the satellite velocity. When the spacecraft
was in the despun mode, the nitrogen density was measured except when the particle stream was interrupted by
the baffle. The sensor was vacuum-sealed prior to launch and opened to the atmosphere after the spacecraft
was in orbit. More experiment details can be found in N. W. Spencer et al., Radio Sci., v. 8, n. 4, p. 287, 1973.
NSSDC has all the useful data that exist from this investigation.