NASA officials announced today (Aug. 15) that the Kepler Space Telescope team has given up trying to repair the spacecraft’s failed reaction wheels and is looking ahead with ideas about what scientific research can still be done by Kepler in its current damaged condition. Kepler’s gyroscope-like reaction wheels are needed to keep the spacecraft steady for precise pointing at distant stars in its search for Earth-like planets.
The first of Kepler’s four reaction wheels failed in 2012. In May of this year, a second wheel stopped functioning, leaving the spacecraft effectively disabled. At least three of the four reaction wheels must be working for precise pointing, NASA said. Since May, engineers have been trying to restore Kepler to working order, but today reluctantly had to admit defeat. However, NASA has not given up hope that the mission may still be able to continue in some fashion.
“Kepler has made extraordinary discoveries in finding exoplanets, including several super-Earths in the habitable zone,” said John Grunsfeld, associate administrator for NASA’s Science Mission Directorate in Washington, DC, in a space agency news release. “Knowing that Kepler has successfully collected all the data from its prime mission, I am confident that more amazing discoveries are on the horizon.”
The Kepler mission, launched in 2009, has revolutionized astronomers’ understanding of exoplanets, or planets beyond our solar system. The mission’s primary goal was to find out how common Earth-like planets that orbit stars similar to our sun are in one region of the Milky Way and, by extrapolation, throughout the entire universe. Kepler has more than lived up to the science community’s expectations by identifying 135 exoplanets and over 3,500 potential ones.
“At the beginning of our mission, no one knew if Earth-size planets were abundant in our galaxy. If they were rare, we might be alone,” said William Borucki, the Kepler mission’s principal science investigator at NASA’s Ames Research Center in Moffett Field, Calif. “Now at the completion of Kepler observations, the data holds the answer to the question that inspired the mission: Are Earths in the habitable zone of stars like our sun common or rare?”
As team members continue to analyze the data from all four years of Kepler’s operation, they expect to make hundreds, “if not thousands,” of new discoveries, NASA said, including ones about the number and location of Earth-like planets that orbit their star in the habitable zone, where conditions are favorable for the presence of liquid water. In addition, NASA engineers will study what modifications would be required to conduct science operations with the Kepler spacecraft using a combination of its remaining two gyroscopic wheels and thrusters for altitude control. The results of these studies, expected to be completed later this year, will inform NASA’s decision about the ultimate feasibility of a two-wheeled Kepler mission.