  Most of our knowledge of planets orbiting nearby stars comes from Doppler
surveys. For spaced-based, high-contrast imaging missions, nearby stars with
Doppler-discovered planets are attractive targets. The known orbits tell
imaging missions where and when to observe, and the dynamically-determined
masses provide important constraints for the interpretation of planetary
spectra. Quantifying the set of planet masses and orbits that could have been
detected will enable more efficient planet discovery and characterization. We
analyzed Doppler measurements from Lick and Keck Observatories collected by the
California Planet Survey. We focused on stars that are likely targets for three
space-based planet imaging mission concepts studied by NASA--WFIRST-AFTA,
Exo-C, and Exo-S. The Doppler targets are primarily F8 and later main sequence
stars, with observations spanning 1987-2014. We identified 76 stars with
Doppler measurements from the prospective mission target lists. We developed an
automated planet search and a methodology to estimate the pipeline completeness
using injection and recovery tests. We applied this machinery to the Doppler
data and computed planet detection limits for each star as a function of planet
minimum mass and semi-major axis. For typical stars in the survey, we are
sensitive to approximately Saturn-mass planets inside of 1 AU, Jupiter-mass
planets inside of ~3 AU, and our sensitivity declines out to ~10 AU. For the
best Doppler targets, we are sensitive to Neptune-mass planets in 3 AU orbits.
Using an idealized model of Doppler survey completeness, we forecast the
precision of future surveys of non-ideal Doppler targets that are likely
targets of imaging missions.
