  The Cold Classical Kuiper Belt, a class of small bodies in undisturbed orbits
beyond Neptune, are primitive objects preserving information about Solar System
formation. The New Horizons spacecraft flew past one of these objects, the 36
km long contact binary (486958) Arrokoth (2014 MU69), in January 2019. Images
from the flyby show that Arrokoth has no detectable rings, and no satellites
(larger than 180 meters diameter) within a radius of 8000 km, and has a
lightly-cratered smooth surface with complex geological features, unlike those
on previously visited Solar System bodies. The density of impact craters
indicates the surface dates from the formation of the Solar System. The two
lobes of the contact binary have closely aligned poles and equators,
constraining their accretion mechanism.
