NEOWISE

NEOWISE (for Near Earth Object Wise) was a second mission for the Wide-field Infrared Survey Explorer (WISE). WISE was a NASA Medium-class Explorer Program (MIDEX) satellite launched in December 2009, for a 1 year mission to survey the sky in infrared. After completing this mission, it was retired in February 2011 while still operational. It was revived in 2013 to carry out a new mission called NEOWISE (for Near Earth Object WISE), specifically to search for near-Earth objects (NEOs), remaining active until July/August 2024, after which it entered Earth atmosphere in November 2024.

Infrared has an advantage over ground visible-light observations in estimating the size of observed NEOs: thermal emission is a greater contributor to such an object's infrared magnitude, which has more relationship to the object's size and less to its albedo than do visible-light magnitudes. NEOWISE was considered so useful that NASA is developing a purpose-built satellite to continue its work, NEO Surveyor.