NASA’s exoplanet-hunting Kepler spacecraft has developed a problem with one of its three remaining reaction wheels. If the wheel fails completely the spacecraft will be unable to accurately point its telescope at the 100,000 stars it is monitoring to detect planetary transits. The problem was announced by Kepler project manager Roger Hunter during a mission update on Thursday. Missions operations and scientific data analysis for the Kepler mission are managed by NASA Ames Research Center in Moffett Field, Calif.
Earlier this month the Kepler team detected an increase in the amount of torque required to turn the #4 reaction wheel. This increase in friction persisted throughout several routine maneuvers of the spacecraft. A similar problem resulted in the failure of reaction wheel #2 in July of last year. While the Kepler spacecraft was designed to be able to continue to function properly with only three wheels, losing another one would probably end the mission.
On Thursday the operations team put Kepler into safe mode for a 10 day rest period to save wear on the wheel and give the spacecraft a chance to redistribute its internal lubricants. Once the 10-day rest period ends, the team will recover the spacecraft from this resting safe mode and return to science operations. That is expected to take approximately three days.
On Jan. 7, the Kepler team announced 461 new planet candidates bringing the planet candidate total to 2,740. Based on observations made during the first 22 months of science operations, the findings show a steady increase in the number of smaller-size planet candidates and the number of stars with more than one candidate. Last week, William Borucki, science principal investigator for NASA's Kepler mission at NASA's Ames Research Center at Moffett Field in Calif. was awarded the prestigious 2013 Henry Draper Medal by the National Academy of Sciences. Borucki is honored for his founding concept and visionary leadership during the development of Kepler, which uses transit photometry to determine the frequency and kinds of planets around other stars.