Testing Collisional Grinding in the Kuiper Belt

We propose a SNAP survey of 56 small Cold Classical TNOs to compare their colors and rate of binarity to larger members of this most-primitive Kuiper belt group. Collisional grinding models that can explain the observed turn-over in the magnitude-frequency distribution imply that small binaries should also be disrupted, but at a brighter, more readily observable threshold. Likewise, collisional erosion could expose differently-colored interior materials. If we do not see a decline in binary rates and a change in color statistics, these observations would pose a challenge to the collisional grinding scenario, suggesting instead that the magnitude-frequency distribution turnover is a more ancient signature of the planetesimal accretion process.