It is standard practice in space science and astronomy to over-engineer objects that need to be launched into orbit, or better yet to another planet. This is done by adding backups and redundancies to systems in order to ensure continued functionality. This shouldn’t come as a surprise to most astronomy aficionados, given the fact that it is just easier and cheaper to add redundancies instead of having to send a repair crew over hundreds of thousands, even millions of miles, or worse, abandon the mission.
This strategy has definitely paid off in the case of the Martian rover Curiosity. Curiosity was launched on the 26th of November, 2011 as part of NASA’s Mars Science Laboratory mission. It contains 2 critical computing systems that act as its brains, yes 2 of them in case one of them malfunctions. This decision to install an additional brain in the rover is what has kept the mission going on until this day. In February of 2013, the rover experienced some technical issues in one of its brains and technicians had to switch over to the other in order to continue the mission while fixing the malfunctioning one. The second brain was what kept the mission going until a few days ago when it too started having glitches.
But the good news is that the first brain has been fixed and will be taking over from the second. This goes on to show the forethought and prudence of the engineers who decided to mount redundant systems to deal with such a scenario.