The Near-Earth Object Surveillance Mission (NEOSM) is a NASA mission concept currently in the formulation phase that is designed to find and characterize the majority of near-Earth asteroids and comets that could potentially cause severe regional damage. The NEOSM mission is optimized for this task, with a survey cadence designed to maximize reliable detection and orbit determination of near-Earth objects (NEOs, which tend to move at faster rates than more distant small bodies in our solar system in the main belt and beyond. The mission is designed to make significant, rapid progress toward the objective given to NASA by the U.S. Congress of finding more than 90% of NEOs larger than 140 m in diameter. By orbiting the Sun-Earth L1 Lagrange point, a constant close distance to the Earth is maintained throughout the 5-year mission duration, allowing for the downlink of full-frame images. Yet the L1 halo orbit maintains a separation from the Earth that is large enough to permit stabilization of the infrared telescope and detectors at their required temperatures (57 K and 40 K for the two filters) through purely passive means. The NEOSM mission employs two thermal infrared channels spanning 4-5 and 6-10 microns (NC1 and NC2, respectively). The NC1 and NC2 HgCdTe detector arrays exist in a 2048 x 2048 format and have been flight qualified, the result of extensive technology development over more than a decade.
The NEOSM mission will repeatedly image a large swath of sky during its 5-year baseline lifetime. These observations will result in full-frame images, extracted source lists, and a database of physical properties such as effective spherical diameter (Mainzer et al. 2019, PDS). For objects with sufficient data, thermal inertia can be computed (e.g., Jiang et al. 2020, AJ, 159, 264; Masiero et al. 2019, AJ, 158, 97), and where archival visible light measurements are available, visible albedo can be determined. The NEOSM survey can be paused if needed so that a particular target of interest can be examined in greater detail. Position-time pairs (tracklets) of candidate moving objects will be delivered to the Minor Planet Center daily.