NASA radar checks out ECAs, Earth-orbit crossing these, in case one is about to wipe out civilization
These images were taken between 3:50 p.m. and 8:45 p.m. EDT on... [DOC] [TLE] Asteroid Detection Negative - NDI - 2011 - Open Evidence Archive [PAR] Morrison 11 (David, NASA official at NASA Ames research center, Asteroid and 
... Scientists estimate that 2000 Earth-crossing asteroids at least a kilometer in 
size have ... what is out there, increase the numbers of detections and get good 
orbits for .... Scientists have estimated that an impact from one of these objects 
would... [DOC] [TLE] Asteroid Detection Affirmative - NDI - 2011 - Open Evidence Archive [PAR] In 2008, NASA's Near Earth Object Program spotted a total of 11,323 objects of 
all ....