  This is an exciting time for the study of r-process nucleosynthesis.
Recently, a neutron star merger GW170817 was observed in extraordinary detail
with gravitational waves and electromagnetic radiation from radio to gamma
rays. The very red color of the associated kilonova suggests that neutron star
mergers are an important r-process site. Astrophysical simulations of neutron
star mergers and core collapse supernovae are making rapid progress. Detection
of both, electron neutrinos and antineutrinos from the next galactic supernova
will constrain the composition of neutrino-driven winds and provide unique
nucleosynthesis information. Finally FRIB and other rare-isotope beam
facilities will soon have dramatic new capabilities to synthesize many
neutron-rich nuclei that are involved in the r-process. The new capabilities
can significantly improve our understanding of the r-process and likely resolve
one of the main outstanding problems in classical nuclear astrophysics.
However, to make best use of the new experimental capabilities and to fully
interpret the results, a great deal of infrastructure is needed in many related
areas of astrophysics, astronomy, and nuclear theory. We will place these
experiments in context by discussing astrophysical simulations and observations
of r-process sites, observations of stellar abundances, galactic chemical
evolution, and nuclear theory for the structure and reactions of very
neutron-rich nuclei. This review paper was initiated at a three-week
International Collaborations in Nuclear Theory program in June 2016 where we
explored promising r-process experiments and discussed their likely impact, and
their astrophysical, astronomical, and nuclear theory context.
