The Space Dust (SPADUS) instrument aboard the Earth-orbiting ARGOS spacecraft: I—instrument description

The Space Dust (SPADUS) instrument is being carried aboard the Advanced Research and Global Observation Satellite (ARGOS). ARGOS was launched into a circular, sun-synchronous polar orbit at ∼850 km altitude on February 23, 1999 on the Air Force ARGOS P91-1 Mission. The instrument provides time-resolved measurements of dust particle flux, mass distribution, and trajectories, as well as high time resolution measurements of energetic charged particles from the SPADUS Ancillary Diagnostic Sensor (ADS) subsystem, during the nominal three-year ARGOS mission. SPADUS uses Polyvinylidene Fluoride (PVDF) dust sensors developed at the University of Chicago. PVDF sensors have been used earlier on the Vega-1 and Vega-2 missions to Halleyʹs Comet, and are currently being carried on experiments aboard the Cassini spacecraft to Saturn, as well as the Stardust spacecraft to Comet WILD-2. The SPADUS PVDF sensors have a total area of 576 cm2, and the SPADUS velocity/trajectory system permits distinction between orbital debris and cosmic (natural) dust, as well as a determination of the orbital elements for some of the impacting particles. The SPADUS instrument measures particle mass over the mass range ∼5×10−11 g (3.3 μm diameter) to ∼1×10−5 g (200 μm diameter), and also measures integral flux for particles of mass >∼1×10−5 g.