In addition to near-Earth objects, NEO Surveyor will likely detect more than a million asteroids in the Main Belt between Mars and Jupiter and about a thousand new comets. By studying the physical and orbital properties of Main Belt asteroids and comets, we can better understand where the NEOs come from.
Unlike asteroids in the Main Belt, which have generally remained in place for billions of years, we know that NEOs are a transitory population. NEO orbits aren't usually stable for longer than a few million years. After a few million years, one of three things will happen to most NEOs: either they will be pulled into the Sun, get ejected from the inner solar system, or they will crash into a planet.
The fact that we see so many NEOs today despite their transitory nature means that they must continually be resupplied from sources in the Main Belt or comet populations. NEO Surveyor will give us more detailed insight into how the NEOs are formed, and what will eventually happen to them.
NEO Surveyor will also yield valuable information about the numbers, sizes, and activity levels of comets, allowing us to better understand the hazard they may pose to Earth as well as their origins. NEO Surveyor's science team includes experts on comet population studies and composition.
While NEOWISE discovered 21 new comets, NEO Surveyor would be expected to discover many times more.