14 DAY TRIAL // NASA's Juno spacecraft shot through Earth's upper reaches in a flyby that was supposed to increase its speed with the help of Earth's gravity. In fact, after the assist, Juno became one of the fastest manmade objects shooting up from 125,000 km/h (78,000 mph) relative to the sun to 140,000 km/h (87,000 mph). That's faster than the Earth around the sun.
Gravity assists like these are common for all deep space probes, and the approach also gave the team a chance to test some of the equipment and see how the probe worked solely on batteries, since it would pass behind the Earth making its solar panels useless.
Unfortunately, the craft went into safe mode sometime during the flyby due to an unknown cause. The NASA team isn't too worried and the probe did pick up the speed it needed and is on track to Jupiter.
But something happened for the failsafe mechanism to trigger and put the probe into a safe mode, in which most equipment is powered down. NASA is still maintaining communications with the probe, so there's no immediate danger.