 The Nimbus 7 SMMR lasted from 25 October 1978 until 20 August 1987.It measured dual-polarized microwave radiances, at 6.63, 10.69, 18.0, 21.0, and 37.0 GHz, from the Earth's atmosphere and surface.Its primary legacy has been the creation of areal sea-ice climatologies for the Arctic and Antarctic.