by Jim Fanson, Kepler, JPL Project Manager
Mission Manager Update
Kepler is now 1.5 million kilometers (930,000 miles) from Earth. At that distance it takes a total of 10 seconds for a command sent from Earth, traveling at the speed of light, to reach the spacecraft and for a reply to arrive back at Earth. Flight controllers call this the "round-trip light time," and take this time delay into account when commanding the spacecraft.
Scientists are analyzing the first calibration data collected when the spacecraft's photometer was positioned as far away from the sun as possible, while engineers are continuing to collect data at various temperatures. With the cover still closed over the front of the telescope, most components are a bit warmer than they will be when the cover is released. The Schmidt corrector, a 1-meter-diameter (39-inch) slightly non-spherical lens at the front of the telescope, is currently at a temperature of -30 degrees Celsius (-22 Fahrenheit), and the primary mirror at the back of the telescope is at -11 degrees Celsius (12.2 degrees Fahrenheit). The focal-plane array of charge-coupled devices (CCDs) is being maintained at its operational temperature of -85 degrees Celsius (-121 degrees Fahrenheit) to minimize detector noise. Commissioning activities continue to go smoothly, and the vehicle is performing well.