Earlier this week, NASA’s planet-hunting Kepler spacecraft suffered a hardware failure; a device that allows the observatory to maintain its position in space malfunctioned. Bobby Braun, professor of space technology, discusses what went wrong and whether this is the end of the Kepler mission.
NASA’s Kepler mission has been a tremendous success. By staring intently at a portion of space, Kepler has proven the existence of a diverse treasure trove of planets around other stars. Fusing scientific curiosity, engineering creativity and cutting-edge technology, the Kepler project has pushed the boundaries of the possible, opening our eyes and minds to the depths of the universe.
Launched in March 2009, the spacecraft has completed the four-year science mission for which it was designed. Doing so, it has confirmed the existence of more than 130 planets and identified more than 2,700 planet candidates, providing known targets for further observational study. Kepler uses reaction wheels to maintain its orientation in space. Three functional wheels are required to achieve its pointing accuracy and there are four of these devices on the spacecraft. One of Kepler’s reaction wheels failed in July 2012 and a second wheel failed this week. The spacecraft is currently in safe mode while NASA engineers try to determine if this malfunction can be resolved. NASA may be able to return one of these wheels to service. But without a fix, the science mission for which this spacecraft was created will come to an end.
If this is indeed the end of the Kepler mission, we should not be disappointed. While it is human nature to want more, in this case, we should simply celebrate what has been achieved. Five years ago, when looking up at the night sky at all those stars, I felt in my gut that there had to be another Earth out there, somewhere. Today, I no longer have to simply believe in Earth-like worlds around other stars. As a result of Kepler and the rapidly emerging field of exoplanet science, we now know that there are billions of planets in the Milky Way galaxy, that planets orbit most stars and that a few percent of the stars in our galaxy have Earth-like planets in their “habitable zone,” where the temperature is not too hot and not too cold.
Kepler has ushered in a golden era in exoplanet science. We will be studying the Kepler data set for years to come. Follow-on NASA missions are currently in development with launches scheduled in the latter part of this decade. When the history of this century is written, the Kepler mission will undoubtedly go down as one of the major scientific achievements of our time.
“Are we alone?” is a question that has likely pervaded our consciousness for as long as people have looked up at the night sky. Thank you Kepler for reaching towards the answer to this question. In the process, you have fundamentally changed the way we view the galaxy and our place within it.
Photo credit: NASA/Ames/JPL. Clusters of Stars in Kepler's Sight
For more information, or to schedule an interview, please contact: