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The satellite 1967-31A (ATS2), launched in April 1967, was unusual in having a low perigee (180 km initially), a near-constant cross-sectional area and a lifetime of more than two years. Its orbit was analyzed to obtain 212 values of air density, mainly at heights between 160 and 190 km, during 14 months of high solar activity between 4 July 1968 and 2 September 1969 (when the satellite decayed). In general the air density exhibits only a weak dependence on solar activity, but the link between density and geomagnetic disturbances is obvious throughout: the two strongest geomagnetic storms, on 1 November 1968 and 15 May 1969 are accompanied by increases in density of 30% and 70% respectively. A profile of density versus height between 150 and 180 km for mid-1969 is also obtained; and a detailed comparison is made with previous results from 1968-59A. (Author).