It's been a rough couple of days for space hardware. On the heels of Dragon's trouble in orbit yesterday comes news that the Curiosity rover on Mars has been put into safe mode and switched to a backup computer. A glitch detected in its main memory banks has halted all science operations until engineers can determine the safest course of action.
This action shouldn't be cause for immediate worry, as events like this are relatively common. Spacecraft out in space and on Mars don't enjoy the protection of a strong magnetic field like we do on Earth. This means they experience a higher amount of radiation, which can mess with computer memory. A cosmic ray hitting the memory chips on Curiosity could flip a single bit from 1 to 0, altering its instructions. This happens on Earth, too, but it's much easier to simply restart a computer on Earth than on Mars.
While in safe mode, Curiosity is still communicating with mission control here on Earth, but has suspended non-essential operations. If the problem does turn out to be a simple memory error, controllers will likely just upload a fresh copy of the operating software to correct the issue. If it's something more serious, Curiosity may be forced to rely on its backup computer for longer, until a more permanent fix is found.