The Kepler Mission was designed to measure the frequency of Earth-size planets in the habitable zone of Sun-like stars .
A crucial component for recovering the underlying planet population from a sample of detected planets is understanding the completeness of that sample—what fraction of the planets that could have been discovered in a given data set were actually detected .
Here we outline the information required to determine the sample completeness , and describe an experiment to address a specific aspect of that question , which is the issue of transit signal recovery .
We investigate the extent to which the Kepler pipeline preserves individual transit signals by injecting simulated transits into the pixel-level data , processing the modified pixels through the pipeline , and comparing the measured transit signal-to-noise ratio ( SNR ) to that expected without perturbation by the pipeline .
We inject simulated transit signals across the full focal plane for a set of observations of length 89 days .
On average , we find that the SNR of the injected signal is recovered at MS = 0.9973 ( \pm 0.0012 ) \times BS - 0.0151 ( \pm 0.0049 ) , where MS is the measured SNR and BS is the baseline , or expected , SNR .
The 1 \sigma width of the distribution around this correlation is \pm 2.64 \% .
We discuss the pipeline processes that cause the measured SNR to deviate significantly from the baseline SNR ; these are primarily the handling of data adjacent to spacecraft re-pointings and the removal of harmonics prior to the measurement of the SNR .
Finally we outline the further work required to characterise the completeness of the Kepler pipeline .