Comment by jacquesm

> Perhaps the test wasnt long enough?

Small (ok, maybe not so small) fortunes are spent on accelerated testing in the space domain. The test and validation gear is immense, using it is extremely expensive (especially when you get to full scale) and access is limited. They may well have been limited to that week for many reasons and conditions being what they are there is a fair chance that the space environment caused an issue that would have shown up if they had had a much longer test but that if there is no trend or if instrumentation is not sufficient simply doesn't show up at all.

For instance, if you're not measuring current into each and every actuator, or if the resolution at which you are sampling is too low then there may well be a developing issue that you are completely blind to.