The baseline mission requirements are:
Find 2/3 of Asteroids Larger than 140 Meters in Diameter
Discover, detect, track, and characterize at least two-thirds of potentially hazardous asteroids >140m effective spherical diameter within a 5-year mission (goal to achieve >90% completeness within 10-12 years).
Assess the Overall Threat Posed by Potential Earth Impactors
Determine the frequency at which potentially hazardous objects (of all sizes) will hit the Earth within the next ~100 years.
Assess the Impact Threat Posed by Comets
Comets can also be Earth impactors. Although there are fewer comets than asteroids, comets tend to be very large, travel at much higher speeds, and can approach Earth with very short warning times. At present, little is known about comets, except that both general classes of comets, short- and long-period, can impact Earth. Thus a goal of the NEO Surveyor for defending our planet is to identify as many comets as possible and improve our overall understanding of the comet population in our solar system.
Determine Orbits and Physical Characteristics of Specific Discovered Objects
Discovering NEOs is not enough! We need to characterize them and understand their physical properties so that we can take appropriate action, should one be found on an Earth-threatening trajectory. To this end, in addition to determining effective spherical diameter, NEO Surveyor is able to derive a discovered object’s shape and rotational state in order to determine whether the object is metallic or carbonaceous, and whether it is a solid body or a pile of rubble. Information such as this will influence the mitigration approach selected to address the impactor threat to Earth.