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The H3 Survey (for Hectochelle in the Halo at High Resolution) spectroscopic survey of about 200,000 select stars in the Milky Way halo. The goal is radial velocity (RV) measurements as well as stellar parameter determination, ultimately to complete the acquisition of the observed stars' six dimensions within phase space (i.e., covering both position and velocity). Gaia provides position and proper motion data and spectrographic observation for radial velocities was initiated in 2017.