NASA's Juno spacecraft has entered safe mode following a flyby of Earth. Juno is a mission to Jupiter, scheduled to arrive there in 2016. Once it gets there, Juno will go into orbit around Jupiter and study its atmosphere and composition to help us learn about how Jupiter formed. In order to get a boost in speed toward its destination, Juno used a 'gravity assist', a maneuver in which a spacecraft can use the gravity of a planet to help accelerate it in a new direction. Juno used Earth to accelerate it toward Jupiter, but was found to be in safe mode when the flyby was complete. A spacecraft enters safe mode as a way to protect itself when it detects a problem.
Despite this setback, the Earth flyby successfully placed Juno on its planned trajectory toward Jupiter. The Juno team has full contact with the spacecraft, and hopefully should have this issue resolved soon.