High concentrations of Sb • and Sb TM were observed in an investigation of atmospheric filter samples collected in connection with Project Star Dust in 1962 and 1963. Sb TM, an (n, 7) activation product of Sb •, was especially abundant in samples from high northern latitudes and altitudes of 55,000 feet or more. A new 'wave' of Sb TM seems to have reached PENTTI KAURANEN ._.6O