<title>Solar Mass Ejection Imager (SMEI) space experiment</title>

Abstract

Abstract : The Solar Mass Ejection Imager (SMEI) space experiment was an operational prototype for a new class of white light heliospheric imager. SMEI was launched on the Coriolis spacecraft in January, 2003, and was deactivated in September, 2011, thus operating almost continuously for more than eight years. Its primary objective was the detection and tracking of interplanetary transients, typically coronal mass ejections (CMEs), in the inner heliosphere. Towards this goal it was immediately effective, observing and tracking several CMEs in the first month of mission operations, with almost 400 detections to follow. SMEI also contributed to many and varied scientific fields, including studies of corotating interaction regions, the high-altitude aurora, zodiacal light, Gegenschein, comet tail disconnections and motions, and variable stars. It was also able to detect and track Earth-orbiting satellites and space debris. Along with its scientific achievements, SMEI also enabled a significantly improved ability to forecast the arrival of CMEs at Earth, thereby establishing the operational utility of heliospheric imaging. This report reviews the SMEI mission and instrument, its scientific and technical accomplishments, and provides a summary discussion of potential next steps for future heliospheric imagers.