The cooperative, international Deep Carbon Observatory (DCO) aims to examine the forms, volumes, and movements of carbon deep in the Earth at an unprecedented scale as well as in unprecedented detail. Success within this decade requires not only new samples, but also new ways of sampling and instruments variously more sensitive, smaller, larger, more robust, and less susceptible to contamination. This grant to the Deep Carbon Observatory headquarters at the Carnegie Institution of Washington provides funds to help develop four pioneering instruments and to conduct three "sandpit" exercises to spur development of several more. "Sandpit" is a term popularized in recent years to describe team?oriented workshops with a specific, collective problem?solving goal and some funds to follow through. The four proposed instruments are the following: a combined instrument for molecular imaging in geochemistry to measure trace amounts of carbon in lower mantle or core mineral phases and transform our estimates of the global carbon budget; a quantum cascade laser-infrared absorption spectrometer for clumped methane isotope thermometry to explore methane formation temperatures; a large-volume diamond anvil cell to explore material properties at very high pressure that have been examined before only in tiny volumes; and an ultrafast laser spectrometer to assess thermodynamic properties, reaction mechanisms, and kinetics of carbon processes at conditions of deep pressure and high temperature. The three sandpit exercises would address high-pressure, high-temperature bioreactors; use of remote sensing (for example, to measure outgassing from volcanoes); and computational resources and software.