The Space Dust (SPADUS) instrument aboard the Earth-orbiting ARGOS spacecraft: II–results from the first 16 months of flight

In a companion paper (Tuzzolino et al., Planet. Space Sci., 2001, to appear) hereafter called Part I, we present a detailed description of the Space Dust (SPADUS) instrument being carried aboard the Earth-orbiting Advanced Research and Global Observation Satellite (ARGOS). In this paper, we focus on examples of the flight data obtained by SPADUS during the first 16 months of the ARGOS mission. We present results obtained from the SPADUS polyvinylidene fluoride (PVDF) dust trajectory system, which measures dust particle flux, mass distribution, velocity and trajectory, as well as results obtained from the SPADUS Ancillary Diagnostic Sensor (ADS) subsystem, which measures energetic charged particles. Included are both raw data and reduced data for the time period from ARGOS launch (February 23, 1999) to June 8, 2000. The PVDF dust trajectory system detected a total of 258 dust impacts over this interval of approximately 470 days. Of these, 24 were D1–D2 type events—where particles impacted and penetrated a D1 sensor, then impacted a D2 rear array sensor—allowing for time-of-flight measurements. Of the 24 D1–D2 impacts on SPADUS, we identified 11 orbital debris particles, 7 interplanetary impactors, and 6 ambiguous impacts. Examples of particle orbits for both debris particles and interplanetary particles are detailed, and the results obtained for orbital debris flux and mass distribution are compared with predictions from an orbital debris model. We also describe transient particle streams detected by the SPADUS trajectory system resulting from the passage of ARGOS through streams of debris particles in Earth orbit.