Ever-present South Atlantic Anomaly damages spacecraft



On 15 June 2001, at 3:56 UT, the Moderate Resolution Imaging Spectroradiometer (MODIS), one of NASAs prime remote sensing instruments on the TERRA spacecraft, was rendered inoperative while on the western flank of the South Atlantic Anomaly (SAA). The SAA is a vaguely-defined, oval-shaped geographic region centered roughly off the east coast of Brazil where the Earth's geomagnetic field is relatively weak at all altitudes. Space science and engineering projects have frequently given insufficient attention to the serious problems of working in this geographic area. Here we illustrate that MODIS is just one of many spacecraft that have had problems, and that these problems are expected to get worse.