  Primordial black holes (PBHs) remain a viable dark matter candidate in the
asteroid-mass range. We point out that in this scenario, the PBH abundance
would be large enough for at least one object to cross through the inner Solar
System per decade. Since Solar System ephemerides are modeled and measured to
extremely high precision, such close encounters could produce detectable
perturbations to orbital trajectories with characteristic features. We evaluate
this possibility with a suite of simple Solar System simulations, and we argue
that the abundance of asteroid-mass PBHs can plausibly be probed by existing
and near-future data.
