A SPACEBORNE NEAR-EARTH ASTEROID DETECTION SYSTEM

We have designed a Solar Mass Ejection Imager (SMEI) to image transien t heliospheric features from Earth orbit over the entire sky every 90 minutes. The instrument is designed to detect changes on this time sca le in the signals from sunlight Thomson-scattered from electrons at a brightness level of tenth magnitude per square degree of sky. We explo re the possibility of using such an instrument to detect asteroids pas sing near the Earth, We estimate that SMEI will detect at least 13 ast eroids per year over similar to 12 m in radius.