What is Wrong with Kepler? - Video Portal
What is Wrong with Kepler?
LT Eric Kinzbrunner, USN
Understanding why the Kepler Spacecraft Original Mission Changed. NASA designed the Kepler spacecraft to detect extrasolar planets, but after several successful years, with many new discoveries, two out of four reaction wheels failed. NASA repurposed Kepler to continue science under the new mission, K2. This thesis has two objectives: to understand how Kepler finds planets and to develop a model to explain why the original mission was no longer possible. The physics of how Kepler detects planets, the transit method, is first described. As part of this description it is shown that pointing noise is the limiting factor of Kepler’s ability to detect planets. The second part of this thesis explores the reason for the pointing error, the solar torque. Furthermore, an analysis of the pointing accuracy using a flat plate solar torque model is carried out. I concluded that the controllability of the failed spacecraft in the presence of the solar torque is the main driver for the new K2 mission and that science out of ecliptic attitudes present challenges from the control point of view.