Mars mix up and data quality

Do you trust the temperature reading on your thermometer? How important is it to us that equipment records the 'correct data'? You may remember a few years ago (six and a half) that NASA landed a couple of robots on Mars - Opportunity and Spirit. Image kindly reproduced according to the licence at: http://en.wikipedia.org/wiki/File:NASA_Mars_Rover.jpg The rovers were scheduled to last for a 90 day misson - well, amazingly, they are still working - although Spirit is stuck in sand and hopes are fading for ...