  The current understanding of dark matter comes largely from measurements of
the total matter content in the universe, from the distribution of gravitating
matter on very large scales, and from rotation curves and velocity dispersions
on sub-galactic scales. However, small-scale structure may well hold the key to
unlocking the particle physics of the still-mysterious 85% of matter in the
universe. Novel small-scale astrophysical probes of new particles and dark
matter will become possible with a large data volume of high-precision
measurements enabled by next-generation gravitational-wave detectors and
advanced astrometry instruments. Cosmic microwave background and large-scale
structure surveys will provide complementary constraints on dark matter models
with unique small-scale signatures. We lay out the studies of small-scale
structures and compact objects as dark matter probes, and summarize the
requirements to achieve the goals.
