INTRODUCTION

The DUST FLUX MONITOR INSTRUMENT (DFMI) consists of a sensor unit (SU), electronics box (EB), and two acoustic sensors mounted to the STARDUST spacecraft.  The SU is mounted to the Whipple shield, the EB is mounted internally to the spacecraft enclosure, one acoustic sensor is mounted to an acoustic plate located on the Whipple Shields first Nextel layer, and one acoustic sensor is mounted to the Whipple Shield bumper plate.

The SU consists of two independent PVDF dust particle sensors (sensor 1 and sensor 2) mounted in a frame.  Each sensor is connected to the EB by a cable with a length of 1 meter.  The combined mass thresholds of  sensor 1 and sensor 2 provide cumulative and differential particle fluxes over the particle mass range from 10-11g to 2X10-4g (particle diameter range 2mm to 518mm) as well as cumulative flux for particles with mass >2X10-4g.

The EB contains the analog and digital electronics, the instrument low voltage power supply and the SU, acoustic sensor, and spacecraft interface connectors.

The acoustic sensors detects particle sizes that are to infrequent to expect impacts on the SU.  One acoustic sensor detects larger infrequent particles that impact the bumper plate and the other acoustic sensor detects those particles that penetrate the bumper and hit the first nextel layer.

The DFMI PVDF dust sensors have three basic goals:

• To monitor the dust environment for spacecraft health and interpretation  of any spacecraft anomalies.
• To measure the flux, mass distribution, spatial distribution, and total fluence of the coma dust.
• To provide the context for the collected dust sample