NASA-Ames Research Center, MS 244-30, Moffett Field, CA 94035

San Jose State University/NASA-Ames Research Center, MS 244-30, Moffett Field, CA 94035

SETI Institute/NASA-Ames Research Center, MS 244-30, Moffett Field, CA 94035

Orbital Sciences Corporation/NASA-Ames Research Center, MS 244-30, Moffett Field, CA 94035

Space Science Office, VP62, NASA-Marshall Space Flight Center, Huntsville, AL 35805

Ball Aerospace and Technology Company, Boulder, CO 80301

E-mail .Haas@nasa.gov Abstract. Kepler’s primary mission is a search for earth-size exoplanets in the habitable zone of late-type stars using the transit method. To effectively accomplish this mission, Kepler orbits the Sun and stares nearly continuously at one field-of-view which was carefully selected to provide an appropriate density of target stars. The data transmission rates, operational cycles, and target management requirements implied by this mission design have been optimized and integrated into a comprehensive plan for Science operations. The commissioning phase completed all critical tasks and accomplished all objectives within a week of the pre-launch plan. Since starting Science, the nominal data collection timeline has been interrupted by two safemode events, several losses of fine point, and some small pointing adjustments. The most important anomalies are understood and mitigated, so Kepler’s technical performance metrics have improved significantly over this period and the prognosis for mission success is excellent. The Kepler data archive is established and hosting data for the Science team, guest observers, and public. The first data sets to become publicly available include the monthly full-frame images, dropped targets, and individual sources as they are Published Data are released through the archive on a quarterly basis; the Kepler Results Catalog will be released annually starting in 2011. Subject headings space vehicles — instruments telescopes Submitted to Astrophys.J. 1.0 INTRODUCTION The Kepler spacecraft was launched into a 372.5 -day, earth-trailing, heliocentric orbit from Cape Canaveral Air Force Station aboard a Delta II 7925 -10

7, 2009 (UTC). In this orbit, the photometer must be rolled 90 ° about its axis every 93 days to keep the solar arrays illuminated and the focal-plane radiator pointed away from the Sun. The nominal roll dates shown in Table 1 determine the primary cycle for Science operations. Data collection is interrupted once a month to earth-point the high-gain antenna and download the stored Science and engineering data. A download takes about 6 hours over Ka-band. The duration of the breaks is significantly longer because calibration data are collected before and after each roll, and the photometer must thermally re-equilibrate before returning to fine point. The on-board solid state recorder (SSR) holds approximately two months data, so data which are unsuccessfully downloaded one month are saved and downloaded during the next monthly contact. To date, the Ka-band performance has been excellent with less than 0.1 % of the data requiring retransmission. Kepler can simultaneously observe up to 170,000 targets at its long-cadence (LC) sampling interval of 29.4 min and up to 512 targets at its short-cadence (SC) sampling interval of 58