Cosmic Dust News

Marc Fries, Cosmic Dust Curator

Volume 5 No. 2 • September 2023

The South Pole Air (SPA) collection consists of a suite of large-area air filters that were used to collect dust particles from large volumes of air near the Amundsen-Scott South Pole Station. During initial examination of the SPA filters for processing, significant tearing was observed to spontaneously occur in the first filter following removal from its nitrogen cabinet. The filter is visibly discolored over the span of area exposed to Antarctic air. The discoloration appears in other filters as well, but not all of them. A small (a few square mms) fragment of the first filter was collected for closer examination. A combination of visible microscopy and Raman spectroscopy revealed that the pores of the filter are filled with a fluffy white evaporite, evidently sulfate derived from the sulfuric acid droplets reported in the filter pores shortly after collection. The sample was collected from a fragment that contained no IDPs as confirmed in the examination. Also, the filters were originally stored in plastic bags and in many cases the bag is adhered to the face of the filter. Processing of the filters is on hold while we examine options for stabilizing the embrittled filters followed by removal of the plastic bags.

Aircraft flights were requested for cosmic dust collection in the coming fiscal year. If approved, these flights would be "piggyback" flights instead of dedicated dust collection flights, on both the ER-2 and WB-57 airframes. No collection timing was specified in order to maximize collection time and number of collected particles. The piggyback option was selected to maximize collection flight time in light of limited success in obtaining dedicated flights in recent years. The collectors will be foam "dry collection" collectors. The overall collection strategy is to collect as many particles as possible on "dry" substrates.