In-flight photometric performance of the 96Mpx Focal Plane Array Assembly for NASA's Kepler exoplanet mission

Kepler is NASA's first space mission dedicated to the study of exoplanets. The primary scientific goal is statistical - to estimate the frequency of planetary systems associated with sun-like stars. Kepler was launched into an Earth-trailing heliocentric "drift-away" orbit in March 2009, and is monitoring 150,000 stars. The instrument detects the faint photometric signals of transits of those systems whose orbital planes are oriented in our line-of-sight. An Earth-Sun analog will produce a transit depth of 80 parts per million (ppm), lasting for at most a few tens of hours, and repeating once per "year". The instrumentation was designed to provide photometric data with a precision of 20 parts per million in 6.5 hours for 12 th magnitude stars, resulting in a signal-to-noise ratio of 4 for an Earth-Sun transit. The stability of the flight system enables the precision of the data that reveal subtle instrumental and astrophysical effects that in turn allow a deeper understanding of the performance of the hardware, to enhanced operational procedures, and to novel post-processing of the data. The data are approaching the sensitivity needed to detect transits of terrestrial planets. Intrinsic stellar variability is now the most significant component of the photometric error budget.