Yesterday afternoon, NASA lost contact with its New Horizons spacecraft for an hour for reasons unknown. This is generally not a good thing when you're working with technology that's 4.5 light hours away, but thankfully, NASA seems to have solved the problem.
According to NASA, the problem was caused by a "hard-to-detect timing flaw in the spacecraft command sequence that occurred during an operation to prepare for the close flyby [of Pluto]". That timing flaw put New Horizons into safe mode, also causing a collective pants-shitting at NASA.
With the problem detected, New Horizons can resume normal operations, and prepare for the July 14 flyby of Pluto. Although some science observations were lost as a result of the day-long shutdown of normal operations, it's not regarded as a big deal by NASA: "In terms of science, it won't change an A-plus even into an A," said New Horizons Principal Investigator Alan Stern of the Southwest Research Institute, Boulder.