SMALL BODY STUDIES WITH THE NEAR-EARTH OBJECT WIDE-FIELD INFRARED SURVEY EXPLORER (NEOWISE) MISSION

The Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) mission has recently completed its extended mission, having greatly exceeded the original goals of its prime mission when it launched in December 2009. Beginning as the Wide-field Infrared Survey Explorer (WISE; Wright et al. 2010), its original primary objective was to carry out a survey of the entire sky in four infrared wavelengths ranging from 3 – 24 microns and study low temperature stars and distant, dusty galaxies. However, the mission proved capable of detecting and characterizing asteroids and comets (Mainzer et al. 2011a). After successfully completing its prime mission in August 2010, and following a brief extension through February 2011, the spacecraft was placed into hibernation.

In December 2013, the spacecraft was reactivated to continue to search for and characterize small bodies using its two remaining channels (3.4 and 4.6 microns; Mainzer et al. 2014). Renamed NEOWISE, it was responsible for discovering the first known Earth Trojan asteroid (Connors et al. 2011), assessing the fraction of carbonaceous objects among the near-Earth object (NEO) population (Mainzer et al. 2011b), determining the sizes and albedos of more than 140,000 main belt asteroids, including members of collisional families (Masiero et al. 2011, 2014), determining the relative numbers, size, and orbital distributions of the Jovian Trojans and HIldas (Grav et al. 2011, 2012) and determining the size and orbital distributions of long- and short-period comets (Bauer et al. 2017). In addition, the mission discovered Comet NEOWISE in 2020, which was visible to naked-eye observers around the world. Although NEOWISE ceased collecting science data at the end of July 2024, it has left a dataset ripe for explorations of small bodies and time-domain photometry, and it has paved the way for the design and construction of the Near-Earth Object Surveyor mission (Mainzer et al. 2023). Launching in late 2027, NEO Surveyor will extend the work of NEOWISE to find, track, and characterize the majority of asteroids and comets large enough to pose a regional impact hazard.