Winds In-Track Results from Dynamo II Sounding Rocket Mission

The Winds In-Track (WIT) instrument was flown July 2021 on the Dynamo II sounding rockets to measure the in-track neutral wind speed in the thermosphere/ionosphere. The Dynamo II mission included two identically equipped sounding rockets that were launched into well-developed meridional daytime dynamo currents. The WIT was part of the neutral wind instrumentation suite to measure the neutral wind vector in the ram direction of the rockets. Gas enters the WIT on the ram side and is modulated by a chopper wheel that allows a puff of gas to travel a known distance and is detected by a fast ionization gauge. Results from laboratory experiments with a cold molecular beam demonstrate the effectiveness of this technique, however in flight with a relatively warmer gas the signal measured is difficult to detect above the noise. Along with these results, a neutral gas velocity selector concept for future flights called the WIT-VS will be presented.