HYPERVELOCITY IMPACT TESTING OF MICROMETEORITE CAPTURE CELLS IN CONJUNCTION WITH A PVDF THIN-FILM VELOCITY TRAJECTORY SENSOR AND A SIMPLE PLASMA VELOCITY DETECTOR

Five different small particle capture cell designs were evaluated for their ability to capture fragments and residue from 10-200 mum diamete r glass projectiles and oblong olivine crystals impacting at 1-15 km/s in sufficient quantity for chemical and isotopic analyses. Aluminum m ulti-foils (0.1-100 mum thick with approximately 10, 100 and 1800 mum spacing), foil covered germanium crystals, and 0.50 and 0.120 g/cm3 Ae rogels, were positioned behind either multi-film (1.4-6.0 mum thick) p olyvinylidene fluoride (PVDF) velocity/trajectory sensor devices or a simple wire-grid plasma velocity detector. All capture cells collected significant amounts of impactor debris behind the PVDF sensors from n ominal 100 mum diameter glass projectiles and olivine crystals which s truck the sensor at velocities up to 6.4 km/s. At velocities >8 km/s l ittle or no debris penetrated the second PVDF film. Results were incon clusive for velocities between 6.5 and 8 km/s. Plasma detector results showed identifiable impactor residue on Al foils for velocities up to 8.7 km/s and impact tracks with apparent debris imbedded in the Aerog els for velocities up to 12.7 km/s. Maximum foil penetration of glass spheres and olivine crystals were the same, but more particulate debri s was associated with olivine crystal ipacts versus glass impacts. Foi l spacing beyond one particle diameter had no effect on total penetrat ion. Aerogels are identified as a capture cell media that warrants fur ther investigation. The Al multi-foil capture cell with 100 mum net sp acers is identified as die most effective of the other designs and off ers the advantages of compact structure, low secondary ejecta from imp acts, and easy recovery of impactor debris for analysis.