NASA Kepler Mission Manager Update 29 April 2013
The team recently completed a monthly science data download April 8-9, 2013, marking the successful completion of Quarter 16 flight operations and the beginning of Quarter 17. The monthly contact also included a quarterly roll of the spacecraft to the spring attitude. The next spacecraft quarterly roll is scheduled for early July.
The team held a NASA-televised press conference on April 18 to announce the discoveries of two planetary systems harboring three super-Earth-size habitable zone planets. The Kepler-62 and Kepler-69 systems, with five and two planets respectively, included Kepler’s smallest habitable zone planets yet found. Prior to this announcement, Kepler had confirmed only two other habitable zone planets, Kepler-22b and Kepler-47c.
This announcement highlighted the progression of the Kepler discoveries to smaller planets like Earth, in more temperate orbits around their host stars. As we move towards the discovery of a true sun-Earth analog, the scientific discussion is expanding beyond the characteristics of the planets and their host stars themselves, to how these characteristics might impact habitability.
Kepler’s reaction wheel #4 continues to exhibit signs of elevated friction levels and occasional torque spikes that appear to indicate a deterioration of the wheel bearing. The team is able to monitor general wheel performance twice weekly during scheduled X-band engineering contacts, but must rely on the high rate monthly downlinks for detailed insight.
All appropriate mitigation steps to prolong wheel life have now been taken. While the wheel may still continue to operate for some time yet, the engineering team has now turned its attention to the development of contingency actions should the wheel fail sooner, rather than later. Initially, these contingencies will focus on preserving fuel, but subsequent goals will be to return the failed wheels to service, perhaps at reduced performance levels, and investigating opportunities for gathering science data using a combination of wheels and thrusters.
