In January 2006, the project was delayed eight months because of budget cuts and consolidation at NASA.[27] It was delayed again by four months in March 2006 due to fiscal problems. At this time the high-gain antenna was changed from a gimballed design to one fixed to the frame of the spacecraft to reduce cost and complexity, at the cost of one observation day per month.
The observatory was launched on March 7, 2009 at 03:49:57 UTC (March 6, 10:49:57 p.m. EST) aboard a Delta II rocket from Cape Canaveral Air Force Station, Florida.[1][6] The launch was a complete success and all three stages were completed by 04:55 UTC. The cover of the telescope was jettisoned on April 7, 2009 and the first light images were taken on the next day.
On April 20, 2009, it was announced that the Kepler science team had concluded that further refinement of the focus would dramatically increase the scientific return. On April 23, 2009 it was announced that the focus had been successfully optimized by moving the primary mirror 40 micrometers (1.6 thousandths of an inch) towards the focal plane and tilting the primary mirror 0.0072 degree.
On May 12, 2009 at 5:01 p.m. Pacific Time (17:01 UTC-8), Kepler successfully completed its commissioning phase and began its search for planets around other stars.
On June 19, 2009, the spacecraft successfully sent its first science data to Earth. It was discovered that Kepler had entered safe mode on June 15. A second safe mode event occurred on July 2. In both cases the event was triggered by a processor reset. The spacecraft resumed normal operation on July 3 and the science data that had been collected since June 19 was downlinked that day.
On October 14, 2009, the cause of these safing events was determined to be a low voltage power supply which provides power to the RAD750processor.[35] On January 12, 2010, one portion of the focal plane transmitted anomalous data, suggesting a problem with focal plane MOD-3 module, covering 2 out of Kepler's 42 CCDs. As of October 2010, the module was described as "failed", but the coverage still exceeded the science goals.
Kepler downloads roughly 90-100 gigabits of science data about once per month - an example of such a download was on 22–23 November 2010.
Once Kepler has detected a transit-like signature, it is necessary to rule out false positives with follow-up tests such as doppler spectroscopy. Although Kepler was designed for photometry it turns out that it is capable of astrometry and such measurements can help confirm or rule out planet candidates.
Kepler downloads roughly 90-100 gigabits of science data about once per month - an example of such a download was on 22–23 November 2010.
Once Kepler has detected a transit-like signature, it is necessary to rule out false positives with follow-up tests such as doppler spectroscopy. Although Kepler was designed for photometry it turns out that it is capable of astrometry and such measurements can help confirm or rule out planet candidates.
No comments:
Post a Comment