Monitoring Mars for Electrostatic Discharges with the DSN

The Deep Space Network antenna DSS-13 was used during 43 sessions of approximately twelve hours duration between Feb. 4 and Apr. 23, 2010, to monitor Mars for electrostatic discharges. Such discharges had been detected with a special detector installed at DSS-13 by Ruf et al. (GRL 36, L13202, 2009) in June of 2006. The discharge signature was enhanced kurtosis (the fourth moment of the signal normalized to the second moment, which is proportional to power) modulated by the Schumann resonance (circum-planet light travel time) of Mars.

Although DSS-13 is an R&D station, the receivers and data processing equipment used were identical to those used by operational DSN stations which routinely track Mars. The signals in four adjacent pairs of ½ MHz channels were digitized and processed to produce samples of kurtosis in real-time. These were then recorded for later analysis. To verify that Mars was the source of any possible events, the antenna was moved off Mars for 45 sec every 5 min. We demonstrated that the DSN can monitor Mars routinely during normal operations without any additional equipment by including a down-link signal in one channel and seeing the kurtosis change as expected as the antenna pointing was changed. We saw no anomalous kurtosis during local thunderstorms. We will report on the analysis of kurtosis data for Mars events.

In a student research project continuing this activity, the signals from operational DSN antennas in Spain engaged in normal down-link operations are being processed for the kurtosis signature which characterizes electrostatic discharges.

This work was performed by the California Institute of Technology Jet Propulsion Laboratory under contract to the National Aeronautics and Space Administration.